PD1抑制剂治疗弥漫大B细胞淋巴瘤和原发纵隔大B细胞淋巴瘤

Chimeric antigen receptor (CAR) T-cell therapy plays a critical role in the treatment of B-cell hematologic malignancies. The combination of PD-1 inhibitors and CAR-T has shown encouraging results in treating patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). However, there are still cases where treatment is ineffective. This study aimed to investigate the role of IL4I1 in the poor efficacy of CD19 CAR-T combined with PD-1 inhibitors in R/R DLBCL and to explore potential mechanisms. Transcriptomic and metabolomic correlation analyses were performed on tumor tissue from DLBCL patients. We employed an in vitro co-culture system consisting of Pfeiffer cells, CD19 CAR-T and macrophages to investigate the underlying mechanisms. It was found that IL4I1 levels were significantly increased in the tumor tissues of R/R DLBCL patients compared to responders. Correlation analysis revealed a positive association between IL4I1 and tryptophan (Trp)-kynurenic acid (Kyn) related metabolites. In the in vitro co-culture model, the presence of IL4I1 inhibited the cytotoxicity of CAR-T cells. Depletion of IL4I1 disrupted the IDO-AHR-Kyn signaling pathway, thereby enhancing the effectiveness of PD-1 inhibitors in combination with CD19 CAR-T for DLBCL treatment. CAR-T-mediated cytotoxicity was significantly inhibited when IL4I1 was present in the in vitro co-culture model. These findings suggest that IL4I1 may be a contributing factor to poor prognosis in R/R DLBCL patients. IL4I1 expression enhances immunosuppression via the IDO-AHR-Kyn pathway, inhibiting the effectiveness of PD-1 inhibitors combined with CD19 CAR-T. Therefore, suppression of IL4I1 may represent a potential target for combination therapy in DLBCL.

Primary mediastinal large B-cell lymphoma (PMBCL) is a specific subtype of diffuse large B-cell lymphoma (DLBCL), which occurs more frequently in young women. PMBCL is an uncommon kind of cancer. R-EPOCH is a common therapeutic regimen that is suitable for patients with PMBCL, and could get a relatively high complete remission rate. However, it may not be effective response in patients with relapsed PMBCL. Immunotherapy appears to be helpful in recent years. Therefore, in this case, a 31-year-old female patient with relapsed PMBCL. Progressive disease was identified after rechemotherapy and target therapy, complete remission can be achieved after switching to PD-1 inhibitor plus targeted therapy. These recurrence, progression, remission and follow-up are all displayed well on 18F-FDG PET/CT. This case with consecutive imaging monitor illustrates that PD-1 inhibitor may be used as a first-line treatment for recurrent PMBCL. In addition, 18F-FDG PET/CT is strongly recommended for monitoring PMBCL include baseline staging, interim response and follow-up study.

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Background Immune checkpoint inhibitors (ICIs) have demonstrated substantial clinical benefit across a wide range of malignancies. With their expanding use, uncommon immune-related events, including hematologic abnormalities and lymphoid proliferations, are increasingly recognized. However, a causal relationship between ICI exposure and lymphoma development remains unproven. Case description We report a 70-year-old woman with moderately to poorly differentiated gastric adenocarcinoma who was diagnosed with diffuse large B-cell lymphoma (DLBCL) during postoperative treatment with FOLFOX chemotherapy combined with the PD-1 inhibitor sintilimab. During therapy, the patient developed recurrent pleural and pericardial effusions. Early pleural fluid cytology revealed atypical lymphoid cells with occasional Epstein–Barr virus–encoded RNA (EBER) positivity, but immunophenotypic and clonality assessments were not performed, precluding a definitive lymphoma diagnosis at that time. Subsequent cytological, immunophenotypic, and molecular studies confirmed Ann Arbor stage IV DLBCL, predominantly presenting as malignant effusions. The patient achieved remission with R-CHOP therapy but later experienced relapsed and refractory disease. Conclusion This case illustrates a temporal association between PD-1 inhibitor–based therapy and the diagnosis of DLBCL. Given the lack of baseline systemic staging, overlapping PET/CT findings, early diagnostic uncertainty in effusion cytology, and potential contributions from chemotherapy-induced immune perturbation and EBV-associated processes, a direct causal relationship cannot be established. This report underscores the importance of comprehensive baseline evaluation and cautious interpretation of atypical lymphoid findings during immunotherapy.

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ABSTRACT Follicular lymphoma (FL) accounts for approximately 35% of all non-Hodgkin lymphomas and can progress to diffuse large B cell lymphoma (DLBCL) at a rate of 2% per year. Here, we present a 56-year-old female patient who was diagnosed with grade 3a FL. Further pathological investigation revealed that the lymphoma had transformed into DLBCL following six courses of R-CHOP regimen, and further disease progression was observed after two courses of R2-GemOx. We ultimately failed to collect hematopoietic stem cells after two courses of R2-ICE. CD-22 CAR-T cell therapy salvaged the patient; however, a new soft tissue mass of 4.8 × 4.1 cm rapidly emerged in the patient’s right lung. Following the observation of strong tissue staining of PD-L1 (90%), the patient was administered PD-1 inhibitor and 26 Gy of radiotherapy and has maintained progression-free survival at more than 15 months of follow-up. Transformed FL with strong PD-L1 expression showed a poor response to standard immunochemotherapy. Our findings support the potential benefit of PD-1 inhibitor and combination therapies in this type of transformed FL.

A significant proportion of patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) exhibit no response to chimeric antigen receptor (CAR) T-cell therapy or suffer from disease progression thereafter. This study investigated the efficacy and safety of salvage therapy with PD-1 inhibitor-based combination treatment and the patient selection after their CAR T-cell therapy. Twenty-one patients with R/R DLBCL and a high tumor burden were treated with CAR T-cell therapy, a treatment that has shown promising results in clinical trials and has been approved by the Food and Drug Administration (FDA) for use in DLBCL. Patients who achieved complete response (CR) with the CAR T-cell therapy received salvage therapy when their disease progressed again. Patients who obtained partial response (PR) or stable disease (SD) with the CAR T-cell therapy received salvage therapy immediately. Salvage therapy consisted of single PD-1 inhibitors or PD-1 inhibitors combined with chemotherapy. We observed the overall response rate (ORR), overall survival (OS), CAR T-cell amplification, the expression of PD-1, CD3+ T cells, cytokines, and the adverse events. For instance, in a clinical trial of LCAR-B38M CAR T-cell therapy, an 88% ORR was observed, with 74% of patients achieving CR and a median duration of response (DOR) of 16 months. The ORR and CR of the salvage therapy were 28.57% and 19.05%, respectively. The ORR and CR were 38.46% and 30.77% in the 13 patients who achieved PR/SD with the CAR T-cell therapy and received salvage therapy 2 months after CAR T-cell infusion. But the ORR and CR were only 12.5% and 0%, respectively, in patients who achieved CR with the CAR T-cell therapy and received salvage therapy when they experienced disease re-progression. The ratio of CAR-T cells on day 7/day 14 was lower in the PR in CAR-T (effective to PD-1) group. Before salvage therapy, the percentage of CD3+ T cells was higher in the PR in CAR-T (effective to PD-1) group. There was no difference in the Common Terminology Criteria for Adverse Events (CTCAE) grades among the four groups in the salvage therapy. PD-1 inhibitor-based salvage therapy in patients with R/R DLBCL following the CAR T-cell therapy could be an effective and safe treatment, especially in patients who achieved PR after the CAR T-cell therapy and received this salvage therapy immediately. Trial registration number: ChiCTR1800019622 and ChiCTR1900025310

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Background Unfit patients with diffuse large B-cell lymphoma (DLBCL) often exhibit poor tolerance to intensive chemotherapy, necessitating alternative therapeutic strategies. This real-world study explored the efficacy and safety of programmed cell death protein 1 (PD-1) inhibitor (e.g., tislelizumab) combined with CD20 monoclonal antibody (e.g., rituximab) in this population. Methods This retrospective cohort study analyzed 7 consecutive adult patients with histologically confirmed diffuse large B-cell lymphoma (DLBCL) who were deemed unfit for standard intensive chemotherapy (Colorectal Cancer Intrinsic Subtypes, CRIS Scoring ≥6, ECOG performance status ≥2, or major organ dysfunction). All patients received PD-1 inhibitor (pembrolizumab 200 mg intravenously every 3 weeks) combined with CD20 monoclonal antibody (rituximab 375 mg/m² intravenously every 3 weeks) at our institution between January 1, 2023, and December 30, 2024. Treatment response was evaluated using Lugano criteria, with progression-free survival (PFS) and overall survival (OS) calculated via Kaplan-Meier analysis. Safety profiles were graded by CTCAE v5.0. Results This real-world pilot study evaluated PD-1/CD20 dual-target therapy in 7 unfit DLBCL patients (median age: 70 years; 85.7% female). Baseline biomarker analysis showed a median CRIS score of 7.0 (96% CI: 6.0–9.0), with notably elevated PD-L1 expression (median CPS: 80; range: 0–90; 71.4% with CPS ≥80). Patients received a median cumulative PD-1 inhibitor dose of 2200 mg (95% CI: 1200–2800 mg) over 251 days (95% CI: 121–576 days), achieving an 85.7% objective response rate (5 complete responses, 1 partial response). A single progression event occurred in a patient with PD-L1 CPS of 0, preventing median PFS estimation. All patients remained alive at the February 28, 2025, data cutoff, with median OS undefined. Safety analysis revealed hematologic toxicities (28.6% grade 2, 28.6% grade 3, 14.3% grade 4) and grade 1 hepatic abnormalities (14.3%), all managed supportively without treatment-related mortality. Conclusion PD-1/CD20 dual-target therapy demonstrated promising efficacy (85.7% response rate) and manageable safety in unfit DLBCL, patients, highlighting its potential as a chemotherapy-sparing regimen. Larger prospective studies are warranted to validate these findings.

Background:Primary central nervous system lymphoma (PCNSL) is a rare and aggressive subtype of diffuse large B-cell lymphoma (DLBCL) with limited frontline treatment options and high relapse rates (Ferreri et al., Nat Rev Dis Primers 2023; Ferreri et al., Lancet Haematol 2017). Although median overall survival (OS) has improved to approximately 26 months and the 5-year OS rate approaches 30% (Calimeri et al., ESMO Open 2021), durable responses remain challenging, particularly in patients ineligible for high-dose methotrexate-based regimens. Bruton's tyrosine kinase (BTK) plays a crucial role in B-cell receptor signaling and the pathogenesis of PCNSL (Xing et al., Front Oncol 2024). Orelabrutinib, a next-generation, highly selective BTK inhibitor with strong central nervous system penetration, has demonstrated encouraging activity in B-cell malignancies. Combining orelabrutinib with immunotherapy and chemotherapy may offer synergistic effects. This study evaluated the safety and efficacy of orelabrutinib plus anti–PD-1 antibody and fotemustine for newly diagnosed PCNSL. Methods:This is an open-label, single-arm, phase I/II trial including adults (≥18 years) with histologically confirmed PCNSL. The study comprised a 3+3 dose-escalation phase (phase I) evaluating orelabrutinib at 100 mg, 150 mg, and 200 mg daily, followed by a dose-expansion phase (phase II) at the recommended phase 2 dose (RP2D). No dose-limiting toxicities were observed during phase I. However, two patients in the 200 mg cohort developed grade 4 thrombocytopenia requiring dose reductions. The RP2D was therefore established at 150 mg. In the phase II cohort, patients were administered orelabrutinib 150 mg daily, anti–PD-1 antibody 200 mg on day 1, and fotemustine 100 mg/m² on day 2, repeating every 21 days for 6 cycles, followed by maintenance therapy. Complete responders continued with orelabrutinib for 3 months and anti-PD-1 therapy for 1 year, while partial responders received the same regimen plus whole-brain radiotherapy. Patients with stable or progressive disease were discontinued and given salvage treatment. The primary endpoint was the objective response rate (ORR), secondary endpoints included disease control rate (DCR), progression-free survival (PFS), OS, and safety as assessed by adverse events (AEs) per NCI-CTCAE version 5.0. Results:As of April 2025, 31 patients were enrolled and received protocol treatment. Twenty-seven patients had post-treatment efficacy assessment (100 mg cohort, n = 4; 150 mg cohort, n = 17; 200 mg cohort, n = 6). The 27 efficacy-evaluable patients had a median age of 62 years (range: 37-70), median KPS of 70 (range: 40–90), and 15 (55.6%) were male. Fifteen patients had double-expressor lymphoma, and 22 (81.5%) had deep brain involvement. Complete response (CR) was observed in 1 (25%) patient in 100 mg cohort, 12 (70.6%) in the 150 mg cohort and 5 (83.3%) in the 200 mg cohort; partial response (PR) was observed in 1 (25%), 3 (17.6%) and 1 (16.7%) in each cohort, respectively. The ORR in each cohort was 50% (100 mg cohort), 88.2% (150 mg cohort) and 100% (200 mg cohort). In total, ORR was 85.2% and DCR was 88.9% among 27 efficacy-evaluable patients. At cutoff date, the median follow-up duration was 33.3 months (95% CI: 30.5–36.1). The median PFS was 8.9 months (95% CI: 7.4–10.4) and the median OS was 22.8 months (95% CI: 0.8–44.8). The 1-year and 2-year PFS rates were 40.0% and 32.0%, respectively, with corresponding OS rates of 68.0% and 48.0% at 1 and 2 years. Of 31 as-treated patients, the most common hematologic AEs were leukopenia (80.6%), anemia (80.6%), thrombocytopenia (74.2%), and neutropenia (51.6%). Grade 3/4 hematologic AEs were primarily thrombocytopenia (45.2%) and leukopenia (25.8%). Non-hematologic AEs included elevated alanine aminotransferase (54.8%), pulmonary infection (48.4%), elevated aspartate aminotransferase (38.7%), fatigue (38.7%), nausea/vomiting (29.0%), and alkaline phosphatase increased(12.9%). Grade 3/4 non-hematologic AEs were mainly pulmonary infections (38.7%). Conclusion:Orelabrutinib plus anti–PD-1 antibody and fotemustine demonstrated promising activity and acceptable safety in newly diagnosed PCNSL, with a high objective response rate. These findings support the potential of orelabrutinib-based chemoimmunotherapy as a promising frontline strategy. The study is still ongoing and final results will be presented in the future. ClinicalTrials.gov registration: NCT04831658.

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Purpose: To explore the impact of PD-1 maintenance therapy on the relapse-free survival (RFS) of patients with diffuse large B-cell lymphoma (DLBCL). Methods: We retrospectively analyzed patients with DLBCL admitted to our center between January 2018 and July 2019 who achieved complete remission (CR) after induction chemotherapy. Forty-five patients who received PD-1 inhibitor maintenance therapy were considered the treatment group. Forty-five patients who did not undergo maintenance treatment during the same period were selected as the control group. The base levels of the two groups of patients were similar. The 2-year RFS rate of the two groups was compared. The correlation between the adverse prognosis factors of the patients and the RFS rate was performed subgroup analysis. Results: The 2-year RFS rates of the treatment and control groups were 86.7% VS 75.6% (P = 0.178), respectively, until July 2021. A single factor analysis showed that patients with International Prognostic Index (IPI) score ≥ 3, non-GCB DLBCL receiving PD-1 inhibitor maintenance treatment, can improve their 2-year RFS (72.2% VS 30.8%, P = 0.022; 88.5% VS 62.5%, P = 0.032). For non-GCB patients, the 2-year RFS of the treatment group can reach 88.5%, while the 2-year RFS of the control group is 62.5%, which is statistically significant (P = 0.032). In all patients treated with PD-1 inhibitors, the adverse reactions were all grade I–II, and there were no grade III–IV adverse reactions. There were no clear adverse events in the follow-up patients in the control group. Conclusion: Maintenance treatment with PD-1 inhibitors can improve the 2-year RFS rate of patients with IPI score of ≥3 and non-GCB DLBCL. This prompts the potential advantage of PD-1 inhibitors in DLBCL maintenance treatment. However, longer follow-ups remain needed to obtain more definite data.

We studied the efficacy and safety of the combined treatment with programmed cell death 1 (PD‐1) inhibitors and anti‐CD19 chimeric antigen receptor (CAR) T‐cell therapy and subsequent PD‐1 inhibitor maintenance treatment in patients with relapsed/refractory (R/R) diffuse large B‐cell lymphoma (DLBCL) and high tumor burden. Forty‐four R/R DLBCL patients with high tumor burden were enrolled in this study. The experimental group of 26 patients received combined therapy with PD‐1 inhibitors and anti‐CD19‐CAR T cells, while the control group of 18 patients received anti‐CD19‐CAR T‐cell therapy alone. The objective response rate (ORR) was 65.39% and 61.11% in the combination and control groups, respectively. The PD‐1 inhibitor maintenance therapy was selected for patients who achieved complete response or partial response in the combination therapy group. Progression‐free survival and overall survival rates in the combination group were higher than those in the control group 3 and 12 months after CAR T‐cell infusion. There was no significant difference in the grade of cytokine release syndrome or immune effector cell associated neurotoxic syndrome between the two groups. In the maintenance therapy group, only eight patients experienced grade 1 Common Terminology Criteria for Adverse Events (CTCAE) and three grade 2 CTCAE. Overall, we found that the ORR was not affected by the combination therapy with PD‐1 inhibitors and anti‐CD19‐CAR T cells. However, patients who had achieved the ORR might benefit from PD‐1 inhibitor maintenance therapy after combination therapy without increased side effects.

Diffuse large B cell lymphoma (DLBCL) expresses abundant programmed death ligand 1 (PD‐L1), which shields tumor cells from immune attacks through the PD‐L1/PD‐1 signaling axis. The mechanism of PD‐L1 overexpression includes the deletion of the 3′end of PD‐L1, which increases its mRNA stability, and the gain or amplification of PD‐L1. Previous studies found two cases of DLBCL carrying an IGH::PD‐L1 by whole genome sequencing. We describe two more such cases by a targeted DNA next‐generation sequencing (NGS) capable of detecting IGH rearrangements, leading to PD‐L1 overexpression. DLBCL with PD‐L1 overexpression is often resistant to R‐CHOP (rituximab, cyclophosphamide, doxorubicin hydrochloride, vincristine and prednisolone). Our patients responded to a combination of R‐CHOP and a PD‐1 inhibitor.

Accumulating research suggests that Epstein-Barr Virus-positive Diffuse Large B-cell Lymphoma (EBV+DLBCL) is associated with immune dysfunction and tumor microenvironment (TME) heterogeneity. While the prognostic role of the TME in EBV-DLBCL is established, its impact on EBV+DLBCL survival remains unclear. Here, we integrated 10X Visium spatial transcriptomics (ST) with single-cell RNA sequencing (scRNA-seq) to map TME heterogeneity in EBV+DLBCL. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses identified PD-1/PD-L1 signaling as a hallmark of EBV+DLBCL’s immunosuppressive TME. Functional validation using the PD-1/PD-L1 inhibitor BMS202 revealed dose-dependent suppression of proliferation and enhanced apoptosis in EBV+Farage cells, with TLR4 emerging as a downstream effector showing EBV-status-dependent regulation. These findings not only link TME-driven PD-1/PD-L1 activation to EBV+DLBCL’s poor prognosis but also provide preclinical evidence for PD-1/PD-L1 blockade as a therapeutic strategy.

Primary central nervous system large B-cell lymphoma (PCNS-LBCL) is a rare, aggressive lymphoma that affects immune-privileged sites. Immune checkpoint molecules have been implicated in its aggressive biology, and promising results have emerged from immune checkpoint inhibitor therapy in relapsed/refractory cases. This study evaluates the tumor microenvironment (TME), immune checkpoint molecule expression, and the relationship with 9p24.1 gene region alterations in a large cohort of PCNS-LBCL, with detailed quantitative analyses. Tissue microarrays were constructed with 57 PCNS-LBCL cases and 45 systemic non-germinal center diffuse large B-cell lymphoma (DLBCL) controls. Immunostaining for CD3, CD8, CD68, CD163, PD-1, PD-L1, PD-L2, EBER in situ hybridization (ISH), and FISH for PD-L1/PD-L2 copy number alterations and translocations were performed. Digital image analysis was used for quantitative evaluations, which were compared with clinical and pathologic parameters. PCNS-LBCL showed significantly lower T-cell and histiocyte presence in the TME compared with nodal DLBCL (P<0.001), independent of preoperative steroid therapy. Cytotoxic T-cell ratio was higher in PCNS-LBCL (P<0.001). PD-1, PD-L1, and PD-L2 expressions in the TME of PCNS-LBCL were 89%, 96%, and 90%, respectively, and were positively correlated with TME density. Tumor cell expressions of PD-L1 and PD-L2 were 31% and 34%, respectively. FISH alterations in the 9p24.1 region were infrequent and did not consistently correlate with protein expression in either PCNS-LBCL or DLBCL. Higher CD8+ T-cell and CD68+ histiocyte counts were associated with better survival in PCNS-LBCL. Lower TME density and high expression of PD-1/PD-L1/PD-L2 in PCNS-LBCL reflect the unique CNS microanatomy and may contribute to poorer prognosis. These findings support the potential benefit of immune checkpoint inhibitors in treating PCNS-LBCL, aligning with ongoing clinical trials and current literature.

ABSTRACT Aims Up to 40% of patients with diffuse large B-cell lymphoma (DLBCL) have relapsed or refractory (R/R) disease after first-line treatment with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone, and outcomes are poor after hematopoietic stem cell transplantation failure. CheckMate 436 (NCT02581631) was a phase 1/2 study to evaluate the efficacy and safety of nivolumab, a PD-1/PD-L1 inhibitor, plus brentuximab vedotin (BV) for the treatment of R/R non-Hodgkin lymphoma. Materials and methods Adult patients received nivolumab plus BV in 3-week cycles. The primary endpoint was overall response rate (ORR). Here, we report the results from the R/R DLBCL cohort (n = 42). Results With a median follow-up of 7.7 months, the ORR was 28.6% (n = 12), and 7.1% (n = 3) of patients achieved a complete response. Median duration of response (95% CI) was 3.6 (1.2–36.5) months. All patients experienced an adverse event (AE), most commonly diarrhea (n = 20, 47.6%). Grade 3/4 and 5 AEs occurred in 24 (57.1%) and 4 (9.5%) patients, respectively. Any-grade treatment-related AEs occurred in 35 (83.3%) patients. No new safety signals were identified. Conclusions Overall, the efficacy data from CheckMate 436 do not support the use of nivolumab plus BV for the treatment of R/R DLBCL.

Background: Primary mediastinal B-cell lymphoma (PMBL) comprises 10% of diffuse large B-cell lymphoma (DLBCL), primarily affecting young adults. Combination chemoimmunotherapy is effective, but there is no consensus on the optimal therapeutic regimen. The randomized IELSG37 study demonstrated no improvement to progression free survival (PFS) when consolidation radiotherapy was administered following chemoimmunotherapy. However, PFS was inferior for patients (pts) treated with R-CHOP-21 (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone every 21 days) compared with other regimens, supporting intensification of therapy beyond R-CHOP-21 in this entity. Programmed-death- (PD-1) ligands PD-L1/PD-L2 are frequently upregulated in PMBL, and the PD-1 inhibitor pembrolizumab (pembro) blocks interaction of PD-1 and PD-L1/2, and subsequent signalling. Pembro has encouraging activity in relapsed/refractory PMBL with an overall response rate of 43% (complete response 23%) and modest toxicity in a phase II study, and is predicted to be synergistic with rituximab. Therefore, there is compelling rationale for combining R-CHOP and pembro as first-line therapy for PMBL. Methods: ALLG-PACIFIC (ACTRN12621001529831p) is a 35 patient, phase II, single arm, open-label study of R-CHOP in combination with pembro for pts with newly diagnosed PMBL. Pts receive 2 cycles of rituximab (375mg/m2) plus pembro (200mg) every 21 days ('window phase') followed by 6 cycles of R-CHOP plus pembro every 21 days ('induction phase') followed by 5 cycles of pembro 400mg every 42 days ('consolidation phase'). Adults (≥18 years) with treatment naïve histologically confirmed PMBL and adequate organ function, no contraindications to R-CHOP and with no active autoimmune disease are eligible. The primary endpoint is 18-month event free survival. A key secondary endpoint is safety of treatment including rates of early discontinuation due to toxicity. Here, we present the results of a planned interim safety analysis. Results: As of 10th July 2024, 12 pts have completed ‘window’ and ‘induction’ treatment phases (ie. 8 cycles). Three pts have withdrawn consent; 1 due to rash during the first window cycle, one due to patient preference to receive treatment off study, and one due to alopecia and nausea following completion of window treatment, who has subsequently consented to remain on the study for efficacy and survival follow up. All 15 pts are included in this safety analysis. All pts had ≥1 adverse event (AE), with 7 pts (47%) experiencing AEs leading to dose delay. Eight pts (53%) experienced ≥1 possible immune related AE (irAE); rash (G2 n=3, G3 n=3) and alanine aminotransferase (ALT) elevation (G2 n=1, G3 n=3), all with alternate possible causative concomitant medications. Twenty five ≥G3 AEs occurred in 12 pts; rash (n=3), ALT elevation (G3 n=3, G4 n=1), sinus tachycardia (G3 n=2), lipase elevation (G3 n=2), infections (G3 n=3), neutropenia (G3 n=2, G4 n=1) febrile neutropenia (G3, n=2), fever (G3, n=1), and one each G3 of anemia, headache, syncope, chylothorax. There was 1 G3 disease related pericardial effusion. There were no G5 AEs or AEs leading to treatment discontinuation per protocol. Conclusions: This interim analysis of ALLG-PACIFIC suggests that R-CHOP-21 in combination with pembro as first-line therapy for PMBL has a manageable safety profile consistent with that expected of the agents involved. There were no unexpected toxicities, however rates of rash and ALT elevation during ‘window’ phase have led to a recommendation to avoid concomitant administration of supportive medications during ‘window’ phase that may precipitate these AEs. (eg. Allopurinol, co-trimoxazole). Study enrolment, safety and efficacy analyses are ongoing.

Abstract Background Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy leads to high overall response rates of ∼80% even in heavily pre-treated diffuse large B-cell lymphoma (DLBCL), though relapse-free survival drops to ∼40% within the first 12 months. There are early data suggesting that inhibiting the programmed cell death protein 1: programmed cell death ligand 1 (PD-1: PD-L1) checkpoint axis may decrease T cell exhaustion and improve CAR T-cell function. However, there is limited data regarding the toxicity of sequencing these two modalities. This case series of three patients with relapsed/refractory DLBCL treated sequentially with CAR T and checkpoint inhibitor explores the immune-related adverse events (irAEs) with this approach. Case Presentation Case 1 is a 47-year-old male with refractory T-cell/Histiocyte-Rich Large B-Cell Lymphoma who was treated initially with pembrolizumab followed by CAR T-cell therapy and developed autoimmune thyroiditis. Case 2 is a 67-year-old male with refractory DLBCL who was treated with CAR T and subsequently pembrolizumab and developed pneumonitis and respiratory failure. Case 3 is a 22-year-old female with primary refractory mediastinal DLBCL who was treated with pembrolizumab following CAR T therapy and subsequently developed a T-cell mediated autoimmune skin reaction. Conclusions T cell exhaustion has been suspected to contribute to poor persistence of CAR T-cells and clinical relapse, which may be overcome by checkpoint inhibition. While the synergy between CAR T-cell therapy and checkpoint inhibition is promising, the interaction may also lead to off-target irAEs. Prospective trials exploring the safety and efficacy of this combination in relapsed/refractory DLBCL are under way.

PURPOSE The Stimulator of Interferon Genes (STING) is a transmembrane protein that plays a role in the immune response to tumors. Single-agent STING agonist MIW815 (ADU-S100) has demonstrated immune activation but limited anti-tumor activity. This Phase Ib, multi-center,dose-escalation study assessed the safety and tolerability of MIW815 plus spartalizumab (PDR001), a humanised IgG4 antibody against PD-1, in 106 patients with advanced solid tumors or lymphomas. PATIENTS AND METHODS Patients were treated with weekly intratumoral injections of MIW815(50-3200 μg) on a 3-weeks-on/1-week-off schedule or once every four weeks, plus a fixed dose of spartalizumab (400mg) intravenously every 4 weeks. RESULTS Common adverse events were pyrexia (n=23; 22%), injection site pain (n=21; 20%), and diarrhea (n=12, 11%). Overall response rate was 10.4%. The maximum tolerated dose was not reached. Pharmacodynamic biomarker analysis demonstrated on-target activity. CONCLUSIONS The combination of MIW815 and spartalizumab, was well tolerated in patients with advanced/metastatic cancers, including in patients with anti-PD-1 refractory disease. Minimal anti-tumor responses were seen.

Classical Hodgkin lymphoma (cHL) has been identified with universal genetic alterations of chromosome 9p24.1, which contains PD-L1/PD-L2 genes. The amplification of 9p24.1 is associated with the increased expression of PD-L1 and PD-L2 on RS cells, which promotes their immune evasion, and subsequently makes cHL sensitive to PD-1 blockade. Several PD-1 inhibitors have shown significant efficacies with overall response rate (ORR) of 70%−90% in relapse/refractory (r/r) cHL and have acquired the approvals for this indication. Recently, more and more studies are conducted to investigate PD-1 blockade in earlier disease course and in combination with neo-agents or chemotherapy. Unlike cHL, non-Hodgkin lymphoma (NHL) consists of numerous subtypes harboring highly biological heterogeneity. Only a few subtypes have been shown to have genetic alteration of9p24.1 including primary mediastinal B cell lymphoma (PMBL), gray zone lymphoma (GZL) with features intermediate between diffuse large B cell lymphoma (DLBCL) and cHL, primary central nervous system lymphoma (PCNSL) and primary testicular lymphoma (PTL). Epstein-Barr virus (EBV)-associated lymphomas have a virally mediated overexpression of PD-L1, also making them sensitive to PD-1 blockade. Therefore, PD-1 inhibitors are less effective in most r/r NHL than in r/r cHL. Further understanding of the biological features of NHL and immune checkpoint inhibitors (ICPi) combined therapy is the research focus in the future. In this review, we outlined the recent progress of ICPi in lymphoma originating from clinical studies.

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Blocking PD-1/PD-L1 signaling transforms cancer therapy and is assumed to unleash exhausted tumor-reactive CD8+ T cells in the tumor microenvironment (TME). However, recent studies have also indicated that the systemic tumor-reactive CD8+ T cells may respond to PD-1/PD-L1 immunotherapy. These discrepancies highlight the importance of further defining tumor-specific CD8+ T cell responders to PD-1/PD-L1 blockade. Here, using multiple preclinical tumor models, we revealed that a subset of tumor-specific CD8+ cells in the tumor draining lymph nodes (TdLNs) was not functionally exhausted but exhibited canonical memory characteristics. TdLN-derived tumor-specific memory (TTSM) cells established memory-associated epigenetic program early during tumorigenesis. More importantly, TdLN-TTSM cells exhibited superior anti-tumor therapeutic efficacy after adoptive transfer and were characterized as bona fide responders to PD-1/PD-L1 blockade. These findings highlight that TdLN-TTSM cells could be harnessed to potentiate anti-tumor immunotherapy.

Checkpoint blockade immunotherapy targeting the PD-1/PD-L1 inhibitory axis has produced remarkable results in the treatment of several types of cancer. Whereas cytotoxic T cells are known to provide important antitumor effects during checkpoint blockade, certain cancers with low MHC expression are responsive to therapy, suggesting that other immune cell types may also play a role. Here, we employed several mouse models of cancer to investigate the effect of PD-1/PD-L1 blockade on NK cells, a population of cytotoxic innate lymphocytes that also mediate antitumor immunity. We discovered that PD-1 and PD-L1 blockade elicited a strong NK cell response that was indispensable for the full therapeutic effect of immunotherapy. PD-1 was expressed on NK cells within transplantable, spontaneous, and genetically induced mouse tumor models, and PD-L1 expression in cancer cells resulted in reduced NK cell responses and generation of more aggressive tumors in vivo. PD-1 expression was more abundant on NK cells with an activated and more responsive phenotype and did not mark NK cells with an exhausted phenotype. These results demonstrate the importance of the PD-1/PD-L1 axis in inhibiting NK cell responses in vivo and reveal that NK cells, in addition to T cells, mediate the effect of PD-1/PD-L1 blockade immunotherapy.

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Introduction: PMBL comprises 10% of diffuse large B-cell lymphoma, primarily affecting young adults. Chemoimmunotherapy is effective, but the optimal regimen is unclear. Pembro is active and tolerable in relapsed/refractory PMBL. There is rationale to combine R-CHOP and pembro as first-line therapy. Methods: ALLG-PACIFIC is a phase II, single arm, open-label study of R-CHOP with pembro for patients(pts) with newly diagnosed PMBL. Pts receive 2 cycles rituximab(R) (375mg/m2) + pembro (200mg) every(Q) 21 days(d) ('window') followed by 6 cycles of R-CHOP + pembro (200mg) Q21d ('induction') followed by 5 cycles of pembro (400mg) Q42d ('consolidation'). Adults ≥18 years with treatment naïve PMBL and adequate organ function, suitable for R-CHOP and no active autoimmune disease are eligible. PET scans are performed at baseline, end of window (EOW), end of induction (EOI), and 18 months from enrolment. For circulating tumor (ct)DNA analysis, libraries were prepared using KAPA HyperCap DS NHL panel (Roche Diagnostics) and sequenced on NovaSeq X Plus (Illumina). Reporter variants(RV) were identified from baseline ctDNA and genomic data was analysed using modified workflow from ctDNAtools (Alkodsi et al., BioRxiv 2020). Logistic regression analysis was performed to evaluate the relationship of baseline total metabolic tumor volume (TMTV) and EOW reduction in SUVmax (ΔSUV) with EOW ctDNA negativity. The primary endpoint is 18-month event free survival, with secondary endpoints ORR, CR, OS, immune-related toxicity (irAE), rates of discontinuation and need for radiotherapy; considered an event. Here, we present results from a planned interim efficacy analysis. Results: At 15th May 2025, 35 pts initiated treatment and are efficacy and safety evaluable. 30 (86%) completed window therapy, with 3 proceeding to induction after cycle 1 due to persistent symptomatic disease. 26 completed induction, and 10 consolidation. Median age was 34 years (range 19-71); 63% were female. 4/35 have withdrawn consent; 2 during window (rash, alopecia/nausea), 1 declining chemotherapy after first induction cycle, and 1 following discontinuation of window due to grade(G)4 pneumonitis. No pts required early transition to induction due to disease progression (PD). 29 pts were evaluable for EOI response, having either completed EOI or reached this timepoint but discontinued therapy prior. EOW ORR was 26/29 (90%), CR 1/29 (3%) and EOI ORR was 25/29 (86%), CR 18/29 (62%), with a single pt having PD at EOI. Excluding the early withdrawals (n=3, above), the EOW ORR was 26/26 (100%), and EOI ORR was 25/26 (96%), CR 18/26 (69%). None of the 7 pts with EOI PR, all Deauville(D) 4, have experienced PD or required radiotherapy. 25/28 pts with baseline ctDNA analysis had suitable RV for monitoring. 11/25 (44%) were EOW ctDNA-. 19 pts had complete imaging for central review (baseline, EOW, EOI) and EOW ctDNA samples. At baseline, median TMTV was 447.7ml (range 68.0-1366.9), and median SUVmax was 22.7 (range 16.0-32.9). The median ΔSUV was 14.9 (range -2.4-28.8). Neither baseline TMTV (p=0.236) or ΔSUV (p=0.259) were associated with ctDNA negativity. The pt with PD had EOW PR (D5) and EOW ctDNA+ (VAF 20.2%) with subsequent EOI PD. They received bridging radiotherapy followed by CAR-T cell therapy, with ongoing MRD- CR at day 90. All other pts had EOW ctDNA VAF <10% (range 0-8.96%). There were no fatal AEs. There were 21 potential irAE; 5 leading to pembro discontinuation-1 during window (n=1 G4 pneumonitis) and 4 during consolidation (n=2 G3 asymptomatic lipase elevation, n=1 G3 cystitis, n=1 G2 esophagitis), with all events resolved or resolving. Other G3 irAE not leading to pembro discontinuation were ALT increase (n=5) and rash (n=4); all during window with potential causative concomitant medications. Other irAE were low grade; rash (G2 n=6), hyperthyroidism (G2 n=1), hypothyroidism (G2 n=1), ALT increase (n=2). Conclusion: This interim analysis of ALLG-PACIFIC suggests that pembro with R-CHOP is effective first-line therapy for PMBL. Almost half of pts achieved ctDNA negativity after 2 cycles of R-pembro prior to initiation of chemotherapy. Outcomes appear comparable to intensive chemotherapy, with low rates of PD at completion of induction therapy. Pembro toxicity may be mitigated in future with treatment de-escalation given the high early ctDNA- rates observed. Enrolment is completed and efficacy, safety and correlative analyses are ongoing.

Patients with relapsed/refractory diffuse large B‐cell lymphoma (R/R DLBCL) have an unmet medical need. The objective of this trial was to assess the efficacy and toxicities of a novel triple immunotherapy regimen—pembrolizumab, low‐dose cyclophosphamide, and maveropepimut‐S (MVP‐S). This regimen was designed to activate tumor‐specific T cells by targeting the tumor‐associated antigen survivin with MVP‐S and reducing two important T cell inhibitory pathways: T cell exhaustion and regulatory T cells with pembrolizumab and metronomic cyclophosphamide, respectively.

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Background: Pembrolizumab 200mg Q3W is approved for treatment of relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and R/R primary mediastinal B-cell lymphoma (PMBCL). The FDA granted accelerated approval topembrolizumab 400 mg Q6W in all approved indications based on data in solid tumors. The global Phase 2 KEYNOTE-B68 trial (NCT04875195) evaluates the efficacy and safety of pembrolizumab 400 mg Q6W in patients with R/R cHL or R/R PMBCL. We previously reported an objective response rate (ORR) of 67% for patients with R/R cHL, and 50% for patients with R/R PMBCL with 16 months (mo) of follow up. Here we present data from 66 patients with an additional 12 mo of follow up. Methods: In this nonrandomized, open-label trial, patients aged ≥18 years with PD-1 inhibitor naïve R/R cHL or PMBCL received 400 mg pembrolizumab Q6W for ≤ 18 cycles, until progression, unacceptable toxicity, or withdrawal. Eligible patients with cHL must have relapsed or failed to respond after ≥1 prior lines of therapy. Eligible patients with PMBCL must have relapsed or failed to respond after ≥2 prior lines of therapy including rituximab and relapsed or failed to respond to or were ineligible for auto-SCT. The primary endpoint was ORR per Lugano criteria by investigator. Secondary endpoints were DOR per Lugano criteria by investigator and safety. Exploratory endpoints were PFS per Lugano criteria by investigator and OS. Data cut-off date was May 13, 2024. Results: At data cut-off, 66 patients (60 R/R cHL, 6 R/R PMBCL) were enrolled. Overall, 53 (80%) patients discontinued treatment, 39 (56%) due to progressive disease, 9 (14%) due to SCT, 2 (3%) due to adverse events (AE), 2 (3%) withdrawals and 1 (2%) due to physician decision. A total of 51 patients with R/R cHL and 6 with R/R PMBCL had ≥2 prior lines of therapy. The median follow-up was 27.7 mo (range, 19.8 -34.7) for patients with R/R cHL and 29.4 mo (range, 23.9 - 34.2) with R/R PMBCL. The ORR was 66.7% (95% CI, 53.3 -78.3 [35.0% CR; 31.7% PR]) for patients with R/R cHL, and 50% (95% CI, 11.8 -88.2 [33.3% CR; 16.7% PR]) for R/R PMBCL. The median DOR was 15.2 mo (range, 0.0+ -29.8+) for patients with R/R cHL and 9.7 mo (range, 2.6 -9.7) for R/R PMBCL. Median PFS was 8.3 mo (95% CI: 5.6-13.8) for patients with R/R cHL and 4.1 mo (95% CI: 0.1 -not reached [NR]) for R/R PMBCL. Median OS was NR (95% CI: NR -NR) for patients with R/R cHL and 24.8 mo (95% CI: 6.7 -NR) for R/R PMBCL. Overall, 22 patients with R/R cHL received transplant (either autologous or allogenic) after stopping trial treatment, 12 had CR and 2 were not-evaluable (NE) after auto-SCT, and 7 had CR and 1 was NE after allogenic stem cell transplant (allo-SCT). Overall, 4 patients with R/R PMBCL received transplant (either autologous or allogenic) after stopping trial treatment, 1 had CR, 1 had PR, and 1 had progressive disease after auto-SCT, and 1 had CR after allo-SCT. Treatment-related AEs occurred in 26 (43%) patients with R/R cHL and 2 (33%) with R/R PMBCL. Grade ≥3 treatment-related AEs occurred in 3 (5%) patients with R/R cHL and 1 (17%) with R/R PMBCL. No grade 5 treatment-related AE occurred. Immune-mediated AEs occurred in 14 (23%) patients with R/R cHL and 1 (17%) with R/R PMBCL. Grade ≥3 immune-mediated AE occurred in 2 (3%) patients with R/R cHL. No grade 5 immune-mediated AEs occurred in patients with R/R cHL and no grade ≥3 immune-mediated AEs occurred in patients with R/R PMBCL. Conclusions: With a total of 28 months of follow-up, pembrolizumab Q6W demonstrated durable responses in patients with R/R cHL and PMBCL and consistent with our previous reports. Additionally, no new safety concerns occurred in either cHL or PMBCL patient populations. The KEYNOTE-B68 trial demonstrates that pembrolizumab 400 mg Q6W maintains antitumor activity in these patients and confirms its acceptability in heme indications.

PURPOSE Patients with relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL) have a poor prognosis, and their treatment represents an urgent and unmet need. Because PMBCL is associated with genetic aberrations at 9p24 and overexpression of programmed cell death-1 (PD-1) ligands (PD-L1), it is hypothesized to be susceptible to PD-1 blockade. METHODS In the phase IB KEYNOTE-013 (ClinicalTrials.gov identifier: NCT01953692) and phase II KEYNOTE-170 (ClinicalTrials.gov identifier: NCT02576990) studies, adults with rrPMBCL received pembrolizumab for up to 2 years or until disease progression or unacceptable toxicity. The primary end points were safety and objective response rate in KEYNOTE-013 and objective response rate in KEYNOTE-170. Secondary end points included duration of response, progression-free survival, overall survival, and safety. Exploratory end points included association between biomarkers and pembrolizumab activity. RESULTS The objective response rate was 48% (7 complete responses; 33%) among 21 patients in KEYNOTE-013 and 45% (7 complete responses; 13%) among 53 patients in KEYNOTE-170. After a median follow-up time of 29.1 months in KEYNOTE-013 and 12.5 months in KEYNOTE-170, the median duration of response was not reached in either study. No patient with complete response experienced progression, including 2 patients with complete response for at least 1 year off therapy. Treatment-related adverse events occurred in 24% of patients in KEYNOTE-013 and 23% of patients in KEYNOTE-170. There were no treatment-related deaths. Among 42 evaluable patients, the magnitude of the 9p24 gene abnormality was associated with PD-L1 expression, which was itself significantly associated with progression-free survival. CONCLUSION Pembrolizumab is associated with high response rate, durable activity, and a manageable safety profile in patients with rrPMBCL.

Key Points • Pembrolizumab monotherapy provides sustained antitumor activity in heavily pretreated R/R PMBCL.• Complete responses were maintained after ∼4 years of follow-up.

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Background: Pembrolizumab 200 mg Q3W demonstrated robust antitumor activity and manageable safety in relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and R/R primary mediastinal B-cell lymphoma (PMBCL), resulting in FDA approval. Recently, the FDA granted accelerated approval of pembrolizumab 400 mg Q6W in all approved indications based on data in solid tumors. The global Phase 2 KEYNOTE-B68 trial (NCT04875195) evaluates the efficacy and safety of pembrolizumab 400 mg Q6W in patients (pts) with R/R cHL or R/R PMBCL. We previously reported ORR of 65% for pts with R/R cHL, and 50% for pts with R/R PMBCL with approximately 9 months (mo) of follow up. Here we present data from 66 patients (pts) with an additional 6 mo of follow up. Methods: In this nonrandomized, open-label trial, pts aged ≥18 years with PD-1 inhibitor naïve R/R cHL or PMBCL received 400 mg pembrolizumab Q6W for ≤ 18 cycles, until progression, unacceptable toxicity, or withdrawal. Eligible pts with cHL must have relapsed or failed to respond after ≥1 prior lines of therapy or relapsed or failed to respond after ≥1 prior multiagent lines of therapy, or autologous stem cell transplant (ASCT). Eligible pts with PMBCL must have relapsed or failed to respond after ≥2 prior lines of therapy including rituximab and relapsed or failed to respond to or were ineligible for ASCT. The primary endpoint was ORR per Lugano criteria by investigator. Secondary endpoints were DOR per Lugano criteria by investigator and safety. Exploratory endpoints were PFS per Lugano criteria by investigator and OS. Data cut-off date was May 15, 2023. Results: At data cut-off, 66 pts (60 R/R cHL, 6 R/R PMBCL) were enrolled. Pts had a median age of 32.5 years (range, 19 to 85), and 35 (53%) were female. Overall, 47 (71%) pts discontinued treatment, 34 (52%) due to progressive disease, 8 (12%) due to ASCT, 2 (3%) due to adverse events (AE), 2 (3%) withdrawals and 1 (2%) due to physician decision. A total of 57 pts with cHL and 5 with PMBCL had ≥2 prior lines of therapy. The median follow-up was 15.7 mo (range, 7.8 -22.7) for pts with R/R cHL and 17.5 mo (range, 12.0 - 22.2) with R/R PMBCL. The ORR was 66.7% (95% CI, 53.3 -78.3 [35.0% CR; 31.7% PR]) for pts with R/R cHL, and 50% (95% CI, 11.8 -88.2 [33.3% CR; 16.7% PR]) for R/R PMBCL. The median DOR was 16.6 mo (range, 1.6 -17.0) for pts with R/R cHL and 9.7 mo (range, 2.6 -9.7) for R/R PMBCL. Treatment-related AEs occurred in 26 pts with R/R cHL and 2 with R/R PMBCL. The most common treatment-related AEs were hypothyroidism in 8 pts with R/R cHL and 1 with R/R PMBCL, and neutropenia in 3 pts with R/R cHL and 1 with R/R PMBCL. Grade ≥3 treatment-related AEs occurred in 3 (5%) pts with R/R cHL and 1 (17%) with R/R PMBCL. No grade 5 treatment-related AE occurred. Immune-mediated AEs occurred in 14 (23%) pts with R/R cHL and 1 (17%) with R/R PMBCL. Grade 3 infusion-related reactions and immune-mediated AE of toxic epidermal necrolysis occurred in 2 (3%) pts and 1 (2%) pt, respectively, with R/R cHL. No grade 4-5 immune-mediated AEs occurred in pts with R/R cHL and no grade ≥3 immune-mediated AEs occurred in pts with R/R PMBCL. Antitumor activity is summarized in the Table. Conclusions: Following 15 months of follow-up the ORR and PFS rates in the cHL patient population have increased, further highlighting the consistency to pembrolizumab 200 mg Q3W as observed in KN-087 and KN-204 patient populations. Additionally, no new safety concerns occurred in either cHL or PMBCL patient populations. This KEYNOTE-B68 trial further demonstrates the continued antitumor activity in patients and confirms the acceptability of Q6W dosing in heme indications.

Background: The tumor microenvironment (TME) plays a role in follicular lymphoma (FL) pathogenesis and survival. PD-1/PDL-1 inhibitors have been effective in non-Hodgkin lymphoma subtypes, such as primary mediastinal B-cell lymphoma, and pembrolizumab + rituximab (P-R) produced a complete response (CR) in 50% of patients with rituximab-sensitive, relapsed/refractory (R/R) FL (Nastoupil ASH 2017, Blood Adv 2022). In 2018, we conducted a phase 2 study to assess the efficacy and safety of P-R in R/R FL and diffuse large B cell lymphoma (DLBCL) including rituximab-resistant patients. Methods: This phase 2, single-center, open-label, non-randomized trial aimed to determine the objective response rate (ORR) of P-R in R/R FL (Arm A) and R/R DLBCL (Arm B). A 3 rd arm with P + Obinutuzumab (O) for R/R FL was added later (Arm C). Eligible patients had R/R disease; for FL, patients must have received prior anti-CD20 therapy and have an indication for treatment; for DLBCL, patients must have relapsed after or be ineligible for autologous stem cell transplantation. Arm A sought to include > 9 patients with rituximab-refractory disease. Weekly R 375 mg/m2 x 4 and 4 doses of P (200 mg in q21 day cycles) were given as induction; responders could receive extended P monotherapy for up to 2 years. In Arm C, patients received weekly O x 4; those with at least SD and clinical benefit could receive P for up to 2 years and 6 more doses of O given every 3 months. CT was used for on-treatment tumor assessments after cycles 4 and 8, then every 12 weeks. A 2-stage design required response at cycle 4 among at least 3 of the first 7 patients in Arm A, and among 3 of the first 9 patients in Arm B, to permit accrual to 20 (Arm A) and 17 patients (Arm B). In Arm C, at least 6 responses in the first 12 patients would be needed to proceed to total accrual of 25 patients. Additional stopping rules were included for excess deaths (>10%) and serious adverse events (SAEs) (>50%). Results: Between 4/2018 and 11/2021, 18 patients were treated on study (Table 1). All were previously treated with rituximab, with 9 refractory to their last rituximab-containing regimen. Median age was 56, 78, and 45 and median prior lines of therapy was 4, 3, and 2 in Arms A, B, and C respectively. In Arm A, 2/7 patients had rituximab-refractory disease, and int- or high-risk FLIPI. All patients in Arm B were refractory to their most recent line of therapy, and 75% had IPI > 3. In Arm A, ORR was 29% (1 CR, 1 PR). In Arm B, no patients responded (6 PD, 1 SD, 1 unevaluable). In Arm C, 3 were accrued and achieved SD as best response. Figure 1 shows outcomes of all accrued patients. Treatment-related adverse events (AE) occurred in 83% of patients, with 9 grade 3/4 AEs occurring in 5 (28%) patients (1 acute kidney injury, 2 diarrhea, 1 hypokalemia, 1 arthralgia, 1 infusion reaction, 1 back pain, 1 generalized muscle weakness, 1 heart failure). There were 5 possible grade 3/4 immune-related AEs, including 2 suspected colitis treated with steroids. With a median follow up of 4.2 years, there were 8 deaths, 6 from progressive lymphoma, 1 from AML likely related to prior therapy, and 1 from a combination of progressive lymphoma and therapy-related AML. Arms A and B closed due to futility, having failed to exceed minimum efficacy for further accrual. Arm C was closed after demonstration of no responses and discussion with the study sponsor following accrual of 3 patients. Conclusion: P-R has modest, expected toxicity but low efficacy in R/R FL and DLBCL patients previously treated with R. Our data align with CHECKMATE-140 in FL (4% ORR, Armand Blood 2021) and data from post-transplant DLBCL (10% ORR post-ASCT, Ansell JCO 2019). Despite similarities in age and FLIPI distribution with data from Nastoupil et al, we failed to confirm those efficacy findings, a finding partly attributable to inclusion of rituximab-resistant patients. Our data suggest limited utility of combined anti-CD20 and anti-PD-1 therapy in R/R FL and DLBCL, and support exploration of alternative strategies to target the TME in these diseases.

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Tumor programmed death‐ligand 1 (PD‐L1) expression in diffuse large B‐cell lymphoma (DLBCL) is associated with inferior outcomes. The first‐line immunologically‐replete setting may be an opportune time for PD‐1 inhibition. We evaluated pembrolizumab in combination with R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) in untreated patients with DLBCL. Eligible patients were age 18 or older, had adequate organ function, and had DLBCL requiring full‐course therapy. Patients received pembrolizumab 200 mg/cycle with R‐CHOP, primarily to assess toxicity. Response assessment utilized standard criteria, and PD‐L1 staining was performed at a validated central laboratory. Among 30 patients, toxicity was comparable to standard R‐CHOP but with two grade ≥3 immune related adverse events (rash, pneumonitis). The overall and complete response rate was 90% and 77%. With 25·5 months of median follow‐up, 2‐year progression‐free survival (PFS) is 83%. PD‐L1 expression was associated with non‐GCB subtype, and improved PFS and survival. Pembrolizumab can safely be added to R‐CHOP, and is associated with a high CR rate and 2‐year PFS. Improved PFS with PR‐CHOP in PD‐L1 expressing tumors contradicts historical data in R‐CHOP treated patients, supporting evaluation of PD‐L1 as a biomarker to identify DLBCL patients who may benefit from this first‐line strategy.

7517 Background: Pembrolizumab (pembro) 200 mg Q3W demonstrated robust antitumor activity and manageable safety in relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and R/R primary mediastinal B-cell lymphoma (PMBCL), resulting in FDA approval. Recently, the FDA granted accelerated approval of pembro 400 mg Q6W in all approved indications based on data from solid tumor trials in solid tumors. The global Phase 2 trial (NCT04875195) evaluates the efficacy and safety of pembro 400 mg Q6W in R/R cHL and R/R PMBCL. We present, for the first time, data from 66 patients (pts) with approximately 9 months (mo) of follow up. Methods: In this nonrandomized, open-label trial, pts aged ≥18 years with PD-1 inhibitor naïve R/R cHL or PMBCL received 400 mg pembro Q6W for ≤ 18 cycles, until progression, unacceptable toxicity, or withdrawal. Eligible pts with cHL must have relapsed or failed to respond after ≥1 prior lines of therapy (LOT) or relapsed or failed to respond after ≥1 prior multiagent LOT or autologous stem cell transplant (ASCT). Eligible pts with PMBCL must have relapsed or failed to respond after ≥2 prior LOT including rituximab and relapsed or failed to respond to or were ineligible for ASCT. The primary endpoint was ORR per Lugano criteria by investigator (Lugano, INV). Secondary endpoints were DOR (Lugano, INV) and safety. Exploratory endpoints were PFS (Lugano, INV) and OS. Data cut-off date was October 18, 2022. Results: At data cut-off, 66 pts (60 R/R cHL, 6 R/R PMBCL) were enrolled. Median follow-up (range) was 8.9 mo (1 – 15.9) for pts with R/R cHL and 10.6 mo (5.1 – 15.4) with R/R PMBCL. The ORR was 65% (95% CI, 51.6 – 76.9 [33.3% CR; 31.7% PR]) for pts with R/R cHL, and 50% (95% CI, 11.8 – 88.2 [33.3% CR; 16.7% PR]) for R/R PMBCL. Drug-related adverse events (AE) occurred in 24 pts (40%) with R/R cHL and 2 pts (33.3%) with R/R PMBCL. Grade ≥3 drug-related AEs occurred in 3 pts (5%) with R/R cHL and 1 pt (16.7%) with R/R PMBCL. Immune-mediated AEs occurred in 13 pts (21.7%) with R/R cHL and 1 pt (16.7%) with R/R PMBCL. Grade ≥3 immune-mediated AEs occurred in 2 pts (3.3%) with R/R cHL. Antitumor activity is summarized in the Table. Conclusions: With approximately 9 mo of follow up, pembro 400 mg Q6W demonstrates robust antitumor activity in pts with R/R cHL and R/R PMBCL. The ORR observed is similar to pembro 200 mg Q3W in R/R cHL and R/R PMBCL. Pembro 400 mg Q6W had no new safety concerns, confirming Q6W dosing in hematologic indications. Clinical trial information: NCT04875195 . [Table: see text]

Background: Lymphocyte-activation gene 3 (LAG-3) is involved in the regulation of T-cell function and is commonly coexpressed with PD-1 on anergic T cells. Favezelimab (MK-4280), a humanized IgG4 anti-LAG-3 monoclonal antibody, plus pembrolizumab (anti-PD-1) is being investigated in the multicohort phase 1/2 MK-4280-003 efficacy and safety study (NCT03598608) in patients with relapsed or refractory (R/R) hematologic malignancies. Prior analyses of the combination demonstrated antitumor activity and manageable safety in patients with anti-PD-1-naive R/R classical Hodgkin lymphoma (cHL; cohort 1; ORR, 73%; CR, 30%) (Johnson NA et al. Blood. 2022;140(suppl 1):6540-2) and anti-PD-1-refractory cHL (cohort 2; ORR, 29%; CR, 9%) (Timmerman J et al. Blood. 2022;140(suppl 1):768-70). We present results from analysis of patients with R/R DLBCL enrolled in cohort 3. Methods: In this study, a safety lead-in phase (part 1) to determine the recommended phase 2 dose (RP2D) was followed by a dose-expansion phase (part 2). In cohort 3, eligible patients were ≥18 years old, had histologically confirmed R/R DLBCL that had progressed after ≥2 lines of previous therapy, including progression after autologous stem cell transplant (ASCT), had declined ASCT, or were ineligible for ASCT. Patients with Richter transformation were not permitted. In part 1, patients received favezelimab at a starting dose of 200 mg that was escalated to 800 mg plus pembrolizumab at 200 mg IV every 3 weeks (Q3W) per the modified toxicity probability interval method. In the dose-expansion phase, patients received favezelimab at the established RP2D of 800 mg plus pembrolizumab 200 mg Q3W for ≤35 cycles (~2 years). Response assessments were performed at weeks 12 and 24 (PET) and Q12W (CT). Adverse events (AEs) were graded per the NCI CTCAE v4.0. The primary end point was safety. ORR per IWG 2007 criteria by investigator review was a secondary end point. Exploratory end points included duration of response (DOR) and progression-free survival (PFS) per IWG 2007 criteria by investigator review and overall survival (OS). Results: A total of 25 patients with R/R DLBCL were enrolled. Patients had a median age of 73 years (range, 25-87), 10 (40%) had ECOG PS 0, and 15 (60%) had ≥3 prior lines of therapy. Most common subtypes of DLBCL were unspecified DLBCL (n = 12; 48%) and germinal center B-cell DLBCL (n = 6; 24%). At database cutoff (March 2, 2023), 1 patient (4%) was ongoing on treatment and 24 (96%) had discontinued because of progressive disease (n = 14), AEs (n = 2), clinical progression (n = 5), or patient noncompliance/nonstudy anticancer therapy (n = 3); 1 patient (4%) discontinued because of treatment-related AEs. No treatment-related deaths occurred. Sixteen patients (64%) had a treatment-related AE; the most common (≥5%) were cough (16%), increased blood alkaline phosphatase (12%), and hypothyroidism, constipation, infusion related reaction, increased AST, muscle spasms, headache and pruritis (8% each). Grade 3 or 4 treatment-related AEs occurred in 4 patients (16%; 1 grade 3 lymphocytic hypophysitis, 1 grade 3 infectious enterocolitis, 1 grade 3 increased AST, 1 grade 3 increased ALT, 1 grade 3 increased amylase, and 1 grade 4 decreased neutrophil count). AEs of clinical interest occurred in 5 patients (20%); only one grade ≥3 occurred (grade 3 hypophysitis). The median (range) time from first dose to data cutoff was 25.9 (19.7-52.1) months. The objective response rate was 12% (95% CI, 2.5-31.2; [2 CR, 1 PR]). Among 17 patients with a postdose scan, 7 (41%) had a reduction from baseline in target lesion size, and 6 (35%) had ≥50% reduction from baseline. Median DOR was not reached (range, 3.0+ to 16.9+ months); 1 responder had an observed response duration of ≥12 months. Median PFS was 2.1 months (95% CI, 1.1-2.7); 12-month PFS rate was 12%. As of the data cutoff, 20 patients (80%) had died. Median OS was 6.4 months (95% CI, 2.3-15.8); 12-month OS rate was 43%. Conclusion: Favezelimab 800 mg plus pembrolizumab 200 mg had limited antitumor activity in patients with DLBCL in cohort 3. Analyses are underway to identify biomarkers predictive of response to the combination of favezelimab and pembrolizumab. The safety profile was manageable and consistent with that observed in other cohorts in the study.

Background: Primary Mediastinal B-cell Lymphoma (PMBL) comprises 10% of Diffuse large B-cell lymphoma (DLBCL), primarily affecting young adults. Combination chemoimmunotherapy with Rituximab, Cyclophosphamide, Doxorubicin, Vincristine and Prednisolone (R-CHOP) is effective, however up to 10-20% of patients may have either refractory disease or experience relapse within 12 months of completing treatment. Consolidative radiotherapy has often been used following R-CHOP, with retrospective data suggesting a survival benefit compared with R-CHOP alone. However, mediastinal radiotherapy increases risk of breast cancer and cardiovascular disease and the recently reported randomised IELSG37 study demonstrated no improvement in progression free survival (PFS) with the use of consolidative radiotherapy following chemoimmunotherapy. Dose-adjusted Etoposide, Prednisolone, Vincristine, Cyclophosphamide, Doxorubicin and Rituximab (DA-EPOCH-R) without radiotherapy has demonstrated excellent activity in a small phase II study but with increased chemotherapy toxicity. In IELSG37, PFS was inferior for patients treated with R-CHOP-21 compared with other chemoimmunotherapy regimens, supporting intensification of therapy beyond R-CHOP-21 in this entity. The outcome for patients with relapsed/refractory PMBL is poor, with response rates of around 25% to second line therapy, and a 2-year overall survival of 15%. Therefore, there remains a need to improve initial therapy for patients with PMBL. Programmed-Death-1 (PD-1) ligands PD-L1/PD-L2 are commonly upregulated in PMBL. The PD-1 inhibitor Pembrolizumab blocks the interaction of PD-1 and PD-L1/2, and subsequent signalling, and has encouraging activity in relapsed/refractory PMBL, with an overall response rate of 43% (complete response 23%) and modest toxicity in a phase II study. ‘Window’ induction treatment involving delivery of checkpoint inhibitor therapy to patients with lymphoma, prior to initiation of chemotherapy has been investigated in phase II studies, showing encouraging efficacy and no safety concerns with this ‘chemotherapy-free’ initial treatment approach. The combination of Pembrolizumab and Rituximab is predicted to be synergistic, and in non-randomised trials in other B-cell lymphoma histologies, has demonstrated superior response rates to those expected with Rituximab monotherapy, suggesting synergism of the combination. There is therefore compelling rationale for combining R-CHOP and Pembrolizumab as first-line therapy for PMBL. This study investigates the efficacy and safety of this novel, time-limited, radiotherapy sparing regimen. Methods ALLG-PACIFIC (ANZCTR- ACTRN12621001529831) is a phase II, single arm, open-label study of R-CHOP in combination with Pembrolizumab. The trial is open to recruitment across Australia. Approximately 35 patients with newly diagnosed PMBL, will be enrolled to receive two cycles of Rituximab (375mg/m 2) plus Pembrolizumab (200mg) once every 21 days ('window phase') followed by six cycles of R-CHOP plus Pembrolizumab once every 21 days ('induction phase') followed by five cycles of Pembrolizumab 400mg once every 42 days ('consolidation phase') (Figure 1). Adults (≥18 years) with treatment naïve histologically confirmed PMBL and adequate organ function are eligible. Key exclusion criteria are the presence of active autoimmune disease, requiring recent immunosuppressive therapy, life-threatening or organ-compromising lymphoma symptoms requiring urgent cytoreductive therapy, and other medically significant conditions that preclude eligibility to receive R-CHOP. Patients who require urgent cytoreductive therapy following initiation of window phase treatment may proceed immediately to induction phase chemotherapy. The primary endpoint is 18-month event free survival. Key secondary endpoints include response to window phase treatment, overall survival, requirement for radiotherapy and safety of treatment including rates of early discontinuation due to treatment toxicity. Several biomarkers are also being investigated for their predictive value for treatment response including minimal residual disease status (measured by Adaptive Immunoseq and CAPP-Seq), PET-CT parameters (e.g., Metabolic tumour volume), and PD-1/PD-L1 expression and 9q24 alterations.

No abstract available

Primary mediastinal B-cell lymphoma (PMBL) is a rare, aggressive B-cell lymphoma that accounts for 2% to 4% of all non-Hodgkin lymphomas, and it typically affects young adults in the third or fourth decade with a slightly higher incidence among females. 1,2 First-line treatment with rituximab and a chemotherapeutic agent is curative for >80% of PMBL cases. In contrast, 10% to 20% are refractory to or relapse after the fi rst treatment approach, mostly within the fi rst 18 months. 3,4 Salvage treatment consists of intensive regimens, followed by autologous stem cell transplantation, but outcomes are poor with a 2-year overall survival (OS) rate of 15% to 29%. 5,6 Immune checkpoint inhibitors (ICIs) restore the T lymphocyte – mediated antitumor effect. In the fi nal analysis of the phase 2 KEYNOTE-170 study, pembrolizumab (a humanized monoclonal immunoglobulin G4 antibody directed against programmed cell death protein 1) in patients with relapsed or refractory (R/R) PMBL yielded an overall response rate (ORR)

No abstract available

TPS7090 Background: The PD-1 inhibitor pembrolizumab is approved globally for the treatment of multiple cancers, including relapsed or refractory (R/R) classic Hodgkin lymphoma (cHL) and R/R primary mediastinal large B-cell lymphoma (PMBCL). Pembrolizumab is currently administered as an intravenous infusion. Subcutaneous administration of pembrolizumab offer advantages to patients, providers, and the healthcare system. MK-3475A is pembrolizumab with berahyaluronidase alfa for subcutaneous administration (subcutaneous pembrolizumab). Berahyaluronidase alfa, a human hyaluronidase variant developed and manufactured by Alteogen Inc., is a permeation enhancer that increases dispersion and allows for subcutaneous administration of pembrolizumab in 1 injection for both Q3W and Q6W dosing. Here, we describe the methodology of a single-arm, open-label, phase 2 study (NCT06504394) designed to evaluate subcutaneous pembrolizumab in participants with R/R cHL or R/R PMBCL. Methods: Key eligibility criteria include participants aged ≥18 years with a histologically confirmed diagnosis of cHL or PMBCL that is FDG-avid per WHO classification criteria, radiographically measurable disease, and an ECOG performance status of 0 or 1. Participants with cHL must be anti–PD-1 naive and have not responded to or relapsed after ≥1 line of multiagent therapy, did not achieve a complete response (CR) or relapsed after autologous stem cell transplant (auto-SCT), or are ineligible for auto-SCT. Participants with PMBCL must be anti–PD-1 naive and have not responded to or relapsed after ≥2 prior lines of therapy (≥1 rituximab based), or did not achieve a CR or relapsed after auto-SCT or are ineligible for auto-SCT. Key exclusion criteria include clinically significant cardiovascular disease, pericardial effusion or clinically significant pleural effusion, or an additional malignancy that is progressing or has required active treatment within the past 2 years. Approximately 60 participants will be enrolled. All participants will receive subcutaneous pembrolizumab 790 mg every 6 weeks for up to 18 cycles (~2 years), or until disease progression or other discontinuation criteria are met. Primary end points are pharmacokinetics during cycle 1 and objective response rate per Lugano classification criteria by investigator review. Secondary end points are pharmacokinetics at steady state (cycle 3), antidrug antibody levels, safety and tolerability, and duration of response per Lugano classification criteria by investigator review. CT scans will be performed every 12 weeks; PET scans will be performed at week 12, week 24, and to confirm CR. Adverse events (AEs) will be monitored throughout the study and for ≤30 days after treatment end (90 days for serious AEs; or 30 days if new anticancer therapy is initiated) and will be graded per NCI CTCAE v5.0. Recruitment is ongoing. Clinical trial information: NCT06504394 .

ABSTRACT Introduction: Primary mediastinal large B-cell lymphoma (PMBL) is a rare subtype of lymphoma, clinically and biologically distinct from diffuse large B-cell lymphoma (DLBCL) that shows overlapping features with classical Hodgkin lymphoma (cHL). If first-line strategies lead to 80–85% of curability, relapse occurs early with a chemo-refractory disease and a poor outcome. The presence of 9p24.1 rearrangement, conducting to the overexpression of the immune checkpoint molecules PDL1 and 2, has paved the way for immune checkpoint blockers development in these entities. Pembrolizumab, an anti PD-1 checkpoint antibody, was initially approved in solid cancer and later on in the lymphoma field in cHL. Areas covered: We summarize the biology and clinical need in PMBL, leading to the rationale for checkpoint inhibitors development, as well as pembrolizumab clinical studies in this entity. To do so, we performed a PubMed search using the terms: ‘PMBCL,’ ‘lymphoma,’ ‘Immune checkpoint,’ and ‘Pembrolizumab.’ Expert opinion: Pembrolizumab showed tolerable safety profile and efficacy data in patients with PMBL who have relapsed after, or are ineligible for autologous stem cell transplant (ASCT). Some combination strategies have shown promising preliminary results, while others are currently being conducted.

Primary mediastinal large B-cell lymphoma (PMBCL) is a subtype of diffuse large B-cell lymphoma (DLBCL). PMBCL comprises approximately 10% of DLBCLs, thus making it a rare variant of DLBCL. Cure rates for PMBCL with upfront regimens like DA-REPOCH exceed 90%. However, if there is a poor response to this first-line therapy, relapsed/refractory PMBCL (rrPMBCL) has limited treatment options. The historic trend is to treat rrPMBCL with salvage regimens commonly used for DLBCL followed by high-dose therapy and autologous stem cell transplant (HDT-ASCT); however, response rates to salvage therapy remain low and few patients are able to proceed to transplant. An interesting feature of PMBCL is that even though it is classified as a subtype of DLBCL, PMBCL actually shares many clinical, pathologic, and genetic features with classical Hodgkin lymphoma (cHL). For example, both frequently express program death ligand 1 and 2 (PD-L1/2), which is not seen in other mature B-cell lymphomas. The expression of PD-L1/2 in PMBCL makes PDL1 inhibitors, such as pembrolizumab, an attractive therapeutic target. Pembrolizumab is an effective and well-tolerated therapy now approved for a number of cancer types from advanced melanoma to relapsed/refractory cHL. There are now multi-institutional trials underway assessing the role of pembrolizumab in the treatment of rrPMBCL.

Patients with relapsed or refractory primary mediastinal B cell lymphoma (R/R PMBCL) have a poor prognosis, with an overall response rate (ORR) to salvage chemotherapy of 25% and a 2-year overall survival (OS) rate after diagnosis of R/R PMBCL of 15%. PMBCL cells overexpress programmed cell death 1 ligand (PDL1), enabling evasion of immune surveillance. Immune checkpoint inhibitors (ICIs) restore the T-lymphocyte mediated anti-tumor effect and have received FDA approval for the therapy of classical Hodgkin lymphoma and PMBCL. Here we presented our monocentric experience with ICIs in the context of R/R PMBCL. Forty-six patients were treated with pembrolizumab (n=31) or with the combination of nivolumab and brentuximab vedotin (nivoBV, n=15) after a median number of previous therapies of 2 (range 1-6), 72% were female. No statistical significant difference occurred in the main characteristics in the two cohorts. After a median number of 3 cycles (range 1-20) for pembrolizumab and 2 for nivoBV (range 1-52), best ORR was for pembrolizumab 54.1% (with 16 complete response [CR]) and 72.7% for nivoBV (with 6 CR). Best response was reached at a median of 3 (range 1-7) cycles for pembrolizumab and of 2 (range 1-4) for nivoBV. Final global ORR was 48.6% with 40.5% of CR rate. Nine patients underwent ICI as bridging therapy (BT) for CAR T-cell obtaining 6 CR, while other 3 patients initially candidates to use ICI as BT to CAR T were re-scheduled to continue ICI that became to all effects a further line of therapy (all obtained a CR after 35-36 cycles and are still in continuous CR). Seventy-two adverse events (AE) occurred in 34 patients, 17 ones were of grade ≥3 and 10 were classified as immune-related AE. In the nivoBV cohort more extra-hematological AEs occurred, both overall (p = 0.006) and considering only those of grade 3-4 (p = 0.0301). Three patients in the nivoBV cohort had an early ICI discontinuation due to an extra-hematological AE. Hematological toxicity was represented only by 9 neutropenia in 9 patients all of grade ≥3 and judged related to therapy. Nineteen patients underwent further therapy after ICI. At a median follow up for the whole study population of five years, median OS was not reached, progression-free survival (PFS) was 47.1% at 8 years with a plateau reached after ten months, disease free survival (DFS) was 100%, and no statistical difference occurred between the two subgroups. At the latest follow up, 28 patients were still alive, 25 in CR and 3 in PR on initial treatment. Among patients in CR, 16 are maintaining continuous CR without any kind of consolidation, 8 achieved CR after CAR T-cell and 1 patient in CR received consolidation therapy with autologous stem cell transplantation. In conclusion our results demonstrate that ICI therapy for R/R PMBCL is associated with high response rate and durable outcomes. The study is still ongoing to expand the sample size due to the rarity of the disease to further investigate the potential of ICIs as BT to CAR T-cell or transplantation and to identify the specific subset of patients who can be cured only with ICIs.

Abstract SPiReL is a phase II clinical trial evaluating combination immunotherapy, pembrolizumab and cyclophosphamide, with maveropepimut-S, in survivin-expressing relapsed/refractory (R/R) Diffuse Large B Cell Lymphoma (DLBCL). We describe baseline tumor survivin expression and associations with clinico-pathological variables in 25 participants. The median number of survivin-expressing cells was 99%, and the intensity of survivin expression within tumors was heterogeneous by semi-quantitative immunohistochemistry assessment. Tumors with higher numbers of cells expressing 2+/3+ survivin were associated with characteristics of poor outcome, (Lactate dehydrogenase and cell-of-origin). Greater total baseline tumor area was associated with lower proportions of 1+ cells and greater proportions of 2+/3+ cells. High intensity survivin expression is associated with aggressive clinical features supporting a pathobiological role in R/R DLBCL. Future prognostic models incorporating survivin as a clinical biomarker require assessment of intensity, overall expression and should include potential threshold effects of survivin in DLBCL pathobiology.

Key Points • AUTO3 ± pembrolizumab for r/r LBCL was safe and, therefore, used in outpatient administration.• AUTO3 ± pembrolizumab showed durable remissions beyond 12 months in 54.4% of complete responders and was associated with robust expansion.

Chimeric antigen receptor T-cell (CAR-T) therapy is a promising option in patients with r/r PMBCL as a radical approach or a part of combined modality treatment. However, failure after CAR-T poses challenges to clinicians. The report presents two cases of patients with r/r PMBCL who received CAR-T therapy following several lines of chemotherapy. The first patient remains in complete metabolic remission 20 months after CAR-T infusion. The second case depicts the use of CAR-T in a combined treatment with bridging therapy to allogeneic haematopoietic stem cell transplantation (allo-HSCT). Combining radiotherapy with pembrolizumab remains a promising salvage therapy in patients who progressed or relapsed after CAR-T. Allo-HSCT is considered a viable consolidation strategy for young and fit patients with r/r disease who respond to bridging therapy. The ideal combination of CAR-T with novel agents and allo-HSCT is still developing and needs to be explored in prospective randomized trials

Background This phase II clinical trial evaluated the R2-GemOx-PD1i regimen, a combination of penpulimab (a modified PD1 inhibitor) with lenalidomide and rituximab, gemcitabine, and oxaliplatin, in treating refractory or relapsed (R/R) diffuse large B-cell lymphoma (DLBCL). Methods Patients received an induction treatment of up to six cycles of R2-GemOx-PD-1i at standard doses every 2 weeks, followed by pembrolizumab and lenalidomide as maintenance or autologous stem cell transplantation (ASCT) as consolidation. The primary objective was to evaluate the complete response rate (CRR) after the induction phase. Results Fifty-four patients were included, including subgroups treated without intent for consolidation with ASCT (N = 38) and those utilizing R2-GemOx-PD1i as a bridge to ASCT (N = 16). The overall response rate (ORR) for all patients was 66.7%, with a CRR of 57.4%. The median progression-free survival (PFS) was 30.4 months, and the median overall survival (OS) was not reached for all patients. Patients receiving R2-GemOx-PD1i without intent for ASCT had ORR and CRR of 63.2% and 52.6%, respectively, with median PFS and OS of 21.2 months and not reached, respectively. Patients receiving R2-GemOx-PD1i as a bridge to ASCT had ORR and CRR of 75.0% and 68.8%, respectively, with median PFS and OS of both not reached, respectively. The most frequent treatment-related adverse events were neutropenia (36, 66.6%) and anemia (32, 59.2%). Hypothyroidism was the most common immune-related adverse event (20 [37.0%]). Conclusion The R2-GemOx-PD1i regimen demonstrated encouraging antitumor activity with manageable toxicity in R/R DLBCL, providing some reassurance about its safety and tolerability. Trial registration ClinicalTrials.gov, NCT05186558 (Dec 23, 2021). Supplementary Information The online version contains supplementary material available at 10.1186/s12916-026-04679-1.

   Introduction. Relapses of primary mediastinal large B-cell lymphoma (PMBСL) with involvement of the central nervous system (CNS) are usually incurable. Therapy tactics in patients with PMBCL with relapse in the CNS have not been defined.   Aim: to present clinical observations of the treatment of relapses of PMBCL with CNS involvement using the “R-PML-CNS-2022” protocol.   Main findings. Two clinical observations of patients with relapses of PMBCL with involvement of the CNS are presented. In both cases, the “R-PML—CNS-2022” protocol was used as a second-line treatment, and a complete remission of the disease was achieved. In the first case, within 6 months after auto-HCT, maintenance therapy with pembrolizumab was performed. Complete remission of the disease continues for 15 months. In the second observation, maintenance therapy with pembrolizumab was also started, however, due to the development of autoimmune complications after 2 cycles, treatment was discontinued. Complete remission of the disease continues for 13 months.   Conclusion. The development of a new strategy for the treatment of relapses of PMLCL with CNS lesion according to the “R-PML—CNS-2022” protocol is a potentially curative approach in this group of patients.

Introduction: Patients with relapsed/refractory (r/r) diffuse large B-cell lymphoma (DLBCL) have poor outcomes, particularly those with progression after autologous stem cell transplant (ASCT) or chimeric antigen receptor T-cells (CAR-T). Although certain subsets of DLBCL may respond to checkpoint blocking antibodies, PD1/CTLA4 dual checkpoint blockade (DCB) has been ineffective in patients with r/r DLBCL with a notable 0% complete remission (CR) rate [Ansell et al 2016]. Homeostatic T-cell expansion and activation achieved by T-cell transfer into lymphodepleted recipients, as is standard in CAR-T therapy or ASCT, is the result of higher levels of “available” trophic cytokines including IL7 and IL15. However, this rapid expansion is coupled with homeostatic upregulation of maturation/exhaustion checkpoints including PD-1 and CTLA-4, leading to homeostatic inhibition which, in turn, can be prevented by DCB, increasing anti-tumor T-cell toxicity [Marshall et al 2019]. Here, we report long term follow-up of 6 patients enrolled on a phase Ib/II study of nivolumab/ipilimumab-primed “immunotransplant” (IT) for r/r DLBCL (NCT03305445). Methods: Six patients with progressive DLBCL following at least one line of standard chemoimmunotherapy were enrolled in Phase Ib of the trial between 2018 and 2020. On day -54, patients received rituximab 375mg/m2, followed by two cycles of DCB (ipilimumab 1mg/kg and nivolumab 3mg/kg q3weeks, starting on day -53), followed by rituximab on day -11 and peripheral blood T-cell harvest. Patients underwent lymphodepletion on day -5 to -3 with fludarabine 30mg/m2/d and cyclophosphamide 500mg/m2/d, followed by autologous T-cell transfer of DCB-primed T cells (IT) on day 0. This was followed by two additional cycles of DCB and maintenance nivolumab 240mg q14days for up to 2 years, intolerance, or disease progression. Results: In long-term follow-up, 2 of 6 patients are in durable CR without receiving subsequent systemic therapy at > 80 months post-IT. Patients received a median of 3.5 prior lines of therapy; 33.3% had received anti-CD19 CAR-T therapy and 33.3% had received prior ASCT. All 6 patients received at least one cycle of DCB. Overall response rate (ORR) was 50% (16.6% CR, 33.3% PR). One patient had progressive disease requiring salvage chemotherapy after one cycle of DCB and was taken off protocol prior to IT. Five patients (83.3%) received at least 2 cycles of DCB and IT. One patient died of unknown cause 1 month after IT (grade 5 TEAE) prior to response assessment. A 74-year-old female with non-germinal center (non-GC) DLBCL who had received 5 prior lines of therapy including ASCT achieved a PR at 1 month post-IT and a CR at 9 months post-IT and remains in durable remission at 82 months. A 47-year-old female with GC-type DLBCL with 4 prior lines of systemic therapy achieved a PR at 2 months post-IT. At 5 months post-IT, she developed localized progression vs pseudo-progression; maintenance nivolumab was stopped. Subsequent scans showed improving systemic tumor regression with continued growth of a left pelvic lesion. She received left pelvic radiotherapy 35 months post-IT and has subsequently remained in CR without additional systemic therapy at 80 months post-IT. A 58-year-old male with non-GC DLBCL with 5 prior lines of therapy including anti-CD19 CAR-T therapy, achieved a PR at 1.5 months post-IT, but had progression at 4 months post-IT. A 61-year-old male with leg-type DLBCL who had progressed after anti-CD19 CAR-T had progression at 2 months post-IT. Treatment emergent adverse events (TEAE) occurred in 100% of patients; grade ≥3 events occurred in 83.3% of patients and were generally related to lymphodepleting chemotherapy. The most common adverse events were fatigue (100%, grade ≥3 16.7%), fever (83.3%, 0%), neutropenia (83.3%, 83.3%), anemia (66.7%, 50%), anorexia (66.7%, 0%), dyspnea (66.7%, 0%), constipation (66.7%, 0%), diarrhea (50%, 0%), and vomiting (50%, 0%). No patients discontinued treatment due to adverse events. Conclusions: Although DCB has been shown to be minimally effective in r/r DLBCL, DCB-primed immunotransplant, a multi-modal approach to augment responsiveness and overcome T-cell exhaustion, led to durable remissions in heavily pre-treated DLBCL patients without subsequent systemic therapy. Further investigation of DCB-primed immunotransplant may uncover efficacy for common tumor types in which DCB has proven ineffective.

Introduction Chemoimmunotherapy with R-CHOP is an established standard of care for diffuse large B-cell lymphoma (DLBCL) but is not curative in all patients (pts). Approximately 20% of DLBCL have aberrations involving the PD-L1/PD-L2 locus. This justifies the investigation of PD-1 checkpoint inhibitors in pts with DLBCL. This Phase 1b study was conducted to determine the maximum tolerated dose (MTD) for nivolumab in combination with R-CHOP in pts with DLBCL and to evaluate the preliminary efficacy of the regimen. Methods Patients with newly diagnosed de novo DLBCL or transformed low-grade lymphoma (tLL) were enrolled from 2019-2022. Treatment comprised a lead-in phase (LIP) with nivolumab 240 mg x 1 followed 2 weeks later by combination nivolumab-R-CHOP given every 3 weeks for 6 cycles. For combination therapy, nivolumab was administered on Day 1 followed by R-CHOP on Days 1-5 (Days 2-6 for Cycle 1). To establish MTD with Phase 1, nivolumab dosing followed a modified 3+3 dose escalation, starting with 1 mg/kg (dose level 1), escalating to 240 mg (dose level 2). MTD was administered for the Phase Ib portion of the study. Primary endpoints were determination of MTD and rate of complete metabolic response (CMR) by PET/CT using Lugano 2014 as best response by completion of 6 cycles of combination therapy (EOT). Correlations of immune subsets with durability of response and toxicity were exploratory. Results Thirty-three patients were enrolled, of which 25 and 22 pts were evaluable for toxicity and efficacy, respectively. The majority were men (n=21, 64%), White (n=26, 79%) with ECOG performance status of 0-1 (n=30, 91%). Twenty-seven (82%) had advanced stage and/or intermediate/high risk IPI score and 20 (65%) had germinal center subtype. Fifteen (45%) and 16 (48.5%) had tLL (2 with prior therapy for LL prior to transformation) and MYC aberrancy (13 with gains; 2 with single-hit and 1 with double-hit rearrangements), respectively. A dose of 240 mg of nivolumab was established as MTD. Twenty of 22 (91%) achieved CMR and 2 partial metabolic response (PMR) by EOT with overall response in 100%. One pt died from COVID-19 after 4 cycles but was in CMR on interim imaging. With median follow-up of 12 months (mo), 4 pts had progression. Both pts with PMR by EOT have not relapsed. Estimated 18-mo OS & PFS were 95.4% & 71.6%, respectively. Correlation of PFS with PD-L1 expression is underway. Most common therapy-related adverse events (TRAEs) attributed to nivolumab-R-CHOP were fatigue in 22 (88%), HTN in 21 (84%), lymphopenia in 21 (84%), and neutropenia in 18 (72%). High-grade (grade 3/4) neutropenia occurred in 15 (60%) with growth factor use per discretion of treating physician. Fifteen (60%) pts had infections, 47% high-grade. Immunotoxicities (IT) were the most common TRAEs attributed to nivolumab in 18 pts (72%), including thyroiditis (n=5, 20%), dermatitis (n=4, 16%), hepatitis (n=3, 12%), and infusion reactions (n=3, 12%). Most common high-grade IT: 1 case each of colitis, hepatitis, myocarditis (discontinued nivolumab), and dermatitis (discontinued nivolumab). For biologic correlates (Figures 1 & 2): non-progressors (NP) were enriched for T regulatory cell (e.g., IFN-γ producing CD4+Foxp3+ phenotype) fragility while progressors (PD) were enriched for exhausted T cell immunophenotype (CD4+PD-1+CD39+) prior to both LIP and initiation of combination therapy (C1D1). Furthermore, exhausted-like T cell levels were significantly reduced at C1D1 in comparison to LIP in NP but not PD. Toxicities correlated to less exhausted-like effector T cell phenotype, decreased CD4+ naïve and central memory T cells, and increased circulating B cells and myeloid-derived suppressor cells. Conclusions This study demonstrates promising efficacy of frontline combination nivolumab-R-CHOP for high-risk DLBCL including pts with intermediate/high risk IPI, tLL, and MYC aberrancy. While limited by small sample size, this regimen resulted in response, PFS, and OS rates above historical rates reported in high-risk pts and provides basis for further evaluation of nivolumab-based therapies in such pts. We found correlations between progression, toxicity and specific immune subset populations. Attention to these biologic correlates as predictors of durable response and toxicity may allow for better patient selection to optimize benefits of therapeutic effect and risks of increased toxicity with nivolumab-based therapies in DLBCL.

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In this issue, Gazeau et al. report on their experience with nivolumab in an attempt to rescue 11 patients that did not achieve a complete remission 30 days after axicabtagene ciloleucel for an R/R DLBCL. With other works detailed in the commentary, it suggests a potential therapeutic benefit of the reversion of CAR T cell exhaustion with antiPD1 therapy. Ongoing clinical trials will help to determine the best candidates and modalities for such salvage. Exhaustion describes a condition in which T cells are unable to perform any function. It has been characterized by chronic infections and cancers.1 Various features within the tumour microenvironment led to dysfunction of T infiltrating lymphocytes, such as antigen persistence, nutrient deprivation and/or PDCD1 demethylation.2 This gene codes for the protein PD1, whose expression is the most known feature of exhaustion. Targeting PD1 with nivolumab or pembrolizumab led to impressive clinical success in the context of various metastatic tumours and Hodgkin lymphoma.3 Even though singleagent antiPD1 showed low and transient antitumor activity in R/R DLBCL,4 with the exception of patients with HIVrelated lymphoma, that may benefit of a longterm disease control.5 About 60 per cent of patients treated with axicabtagene ciloleucel for a relapsing or refractory diffuse large B cell lymphoma (R/R DLBCL) do not achieve a persistent response.6 Massive research effort has been undertaken to dissect CAR T cell failure. Among other causes, absence/low expansion, functionality or persistence of those engineered T cells had been related to exhaustion features. These characteristics have been described among harvested T cells, CAR T cells from the final product and/or circulating CAR T cells, themselves linked to tumour burden, tumour microenvironment and/or systemic inflammation.7 In this issue, Gazeau et al. report on their experience with nivolumab in that context. With that drug, they have been trying to rescue 11 patients that did not achieve a complete remission 30 days after axicabtagene ciloleucel for a R/R DLBCL. They treated patients in 3 different situations. The “primary refractory” group included patients who showed stable or progressive disease at initial evaluation, the “booster” group included patients who achieved a partial response and were belief to require additional therapy, and the “salvage” group included patients who progressed after achieving a partial response and therefore required salvage therapy. Nivolumab was administrated every 2 weeks, and efficacy was evaluated by PET/CT after four injections. Regarding safety, four mild respiratory tract infections were reported, and no CRS/ICANS was observed. Four patients achieved a complete response after 2 months of treatment, two patients were in the situation of partial response at D30 and two others were experiencing relapsing disease after a partial response. A second expansion of circulating CAR T cells was observed, after a single injection of nivolumab, which argues on reversion of CAR T cell exhaustion: Cmax was 0.035 G/L, lower that the initial expansion but following a long period when the CAR T cells were undetectable. Moreover, the secretion of proinflammatory cytokines is probably reflecting the functionality of those CAR T cells. Another group recently reported three patients with early progression or relapse, after being treated with 41BB

Introduction: Molecular minimal residual disease (MRD) status correlates with disease relapse in patients (pts) with diffuse large B cell lymphoma (DLBCL). However, the clinical impact of early treatment intervention a time of detectable MRD (dMRD) prior to clinical relapse is unknown. Checkpoint inhibitor (CPI) therapy has activity in some pts with DLBCL. We hypothesized that early CPI therapy in patients with dMRD without clinical relapse may lower relapse rate. We conducted a pilot study in high risk pts in remission after most recent line of therapy (LOT) in whom maintenance nivolumab (MN) was offered at time of dMRD to assess effect on MRD clearance and relapse rate. Methods: Pts >18 years (yrs) with high-risk DLBCL (ABC-subtype, high grade B cell lymphoma (HGBCL), MYC translocation, relapsed/refractory disease, or Ki67 >90%) who had achieved CR on most recent LOT were eligible. Patients were monitored for detectable MRD (dMRD) based on the clonoSEQ assay for circulating tumor DNA (ctDNA). Pts had monthly MRD assessment and every 4 month imaging for 2 yrs. If conversion from uMRD to dMRD without clinical relapse, pts received MN (240 mg IV q2 weeks) for up 2 yrs. Pts with overt relapse at time of dMRD or dMRD at initial MRD assessment were ineligible for MN. The primary endpoint was rate of conversion from dMRD to undetectable MRD (uMRD). Results: 20 pts were screened and 15 pts enrolled between June 2018 and March 2022. 4 had transformed DLBCL (2 from FL, 1 from MZL, and 1 Richter’s transformation from CLL), 2 pts had HGBCL (one of which was also transformed). All pts with dMRD had radiographic relapse within 4 months of molecular relapse. No pts with uMRD by ctDNA had clinical relapse on study during 2 yrs follow up. Of the 8 pts who enrolled after first LOT, none had molecular or clinical relapse. Of the 7 pts with 2+ prior LOT, 3 had dMRD: two had clinical relapse at same time as dMRD and were taken off study (one had dMRD at baseline MRD assessment and the other 135 days post enrollment after initial period of uMRD). In the single patient eligible for MN, dMRD preceded radiographic relapse by 105 days, 410 days after enrollment. The pt received 2 cycles of MN before clinical progression and was taken off study. This pt failed to achieve conversion of dMRD to uMRD. Conclusion: Due to small sample size and lower than expected relapse, we were unable to demonstrate conversion of dMRD to uMRD using MN. However, this pilot study did confirm high correlation of uMRD and dMRD status with disease free survival and clinical relapse within 4 months, respectively. If strong negative predictive value is confirmed in a larger study, ctDNA MRD testing may be used to spare pts from imaging or to guide additional work up in pts with inconclusive findings on scans. Citation Format: Shazia Nakhoda, Tamarrah Sklarz, Cheyenne Pagan, Matthew Matasar, Zachary A. Frosch, Marcus Messmer, Asya Varshavsky Yanovsky, Rashmi Khanal, Carlyn Tan, Eli Mikkelsen, Henry Fung, Eric Ross, Mark Roschewski, Allison Jacob, Nadia Khan. Circulating tumor DNA and nivolumab maintenance: A pilot study in diffuse large B cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT245.

PURPOSE Treatment options are limited for patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). Tumor cells can exploit the programmed death-1 checkpoint pathway to evade immune surveillance. In the current study, we evaluated the efficacy and safety of programmed death-1 blockade by nivolumab in patients with relapsed/refractory DLBCL. METHODS In this phase II, open-label study, patients with relapsed/refractory DLBCL who were ineligible for autologous hematopoietic cell transplantation (auto-HCT) or who had experienced failure with auto-HCT received nivolumab 3 mg/kg every 2 weeks. We assessed the efficacy and safety of nivolumab as well as genetic alterations of 9p24.1. RESULTS Among 121 treated patients, patients in the auto-HCT-failed cohort (n = 87) received a median of four nivolumab doses and a median of three doses were administered to those in the auto-HCT-ineligible cohort (n = 34). At a median follow-up of 9 months in the auto-HCT-failed cohort and 6 months in the auto-HCT-ineligible cohort, independently assessed objective response rates were 10% and 3%, and median durations of response were 11 and 8 months, respectively. Median progression-free survival and overall survival were 1.9 and 12.2 months in the auto-HCT-failed cohort and 1.4 and 5.8 months in the auto-HCT-ineligible cohort respectively. All three patients with complete remission-3% of the auto-HCT-failed cohort-had durable response (11 or more, 14 or more, and 17 months). Treatment-related grade 3 and 4 adverse events were reported in 24% of patients. The most common were neutropenia (4%), thrombocytopenia (3%), and increased lipase (3%). Of all evaluable samples for 9p24.1 analysis, 16% exhibited low-level copy gain and 3% had amplification. CONCLUSION Nivolumab monotherapy is associated with a favorable safety profile but a low overall response rate among patients with DLBCL who are ineligible for auto-HCT or who experienced failure with auto-HCT. Genetic alterations of 9p24.1 are infrequent in DLBCL.

Key Points • Patients with DLBCL Richter transformation of CLL have a poor prognosis, especially if they have had prior BTKi exposure.• Nivolumab and ibrutinib combination therapy is a safe and potential treatment option in patients with DLBCL Richter transformation.

Introduction Molecular minimal residual disease (MRD) has been shown to correlate with disease relapse in patients (pts) with Diffuse Large B cell Lymphoma (DLBCL)[1-4]. However, the clinical impact of detectable MRD (dMRD) prior to clinical relapse is unknown. Checkpoint inhibitor (CPI) therapy has some activity in certain pts with DLBCL, particularly after CAR-T therapy attributed to effects on T cell activity [5-8]. We hypothesized that early intervention with CPI may lower relapse rate in pts with molecular recurrence only. Patients were monitored for detectable MRD (dMRD) by circulating tumor DNA (ctDNA) using the clonoSEQ assay monthly. We conducted a pilot study in high risk pts in remission after most recent line of therapy (LOT) in which maintenance nivolumab (MN) was offered at time of dMRD to assess effect on MRD clearance and relapse rate. Methods Pts >18 years with high-risk DLBCL (ABC-subtype, high grade B cell lymphoma (HGBCL), MYC translocation, relapsed/refractory disease, or Ki67 >90%) who had achieved CR on most recent LOT. Pts had monthly MRD and every 4 month CT or PET/CT and exam for 2 years. If conversion to dMRD without clinical relapse, pts received MN (240 mg IV q2 weeks) until clinical relapse or toxicity for up to 2 years (26 cycles). Pts with overt relapse at time of dMRD were ineligible for MN and taken off trial. The primary endpoint was rate of conversion from +MRD to undetectable MRD (uMRD) in pts receiving . Results 20 pts were screened and 15 pts were enrolled between June 2018 and March 2022. 5 pts had non-GCB subtype, 2 had GCB subtype, and two had unknown cell of origin. 4 had transformed DLBCL (2 from FL, 1 from MZL, and 1 Richter's), 2 pts had HGBCL (one of which was also transformed). Of the 8 pts who enrolled after 1 prior LOT, none had molecular or clinical relapse (Figure). In 7 pts who enrolled after 2+ prior LOT, 3 had dMRD. 2/3 had clinical relapse at same time as dMRD and were taken off study– one at initial enrollment with dMRD at first ctDNA screening and one converting from uMRD to dMRD after 135 days post enrollment. In the single patient who was eligible for MN, dMRD preceded radiographic relapse by 105 days, 410 days after enrollment. The pt went on to receive 2 cycles of MN before clinical progression and was taken off study. This pt failed to achieve conversion of dMRD to uMRD. Conclusions Due to small sample size and lower than expected relapse rates, we were unable to demonstrate conversion of dMRD to uMRD using MN. Of the 3 pts with dMRD, 2 were not eligible for MN due to clinical relapse at same time as dMRD and both died due to lymphoma progression. In the single pt who received MN, this intervention did not achieve uMRD or prevent relapse. However, this pt went on to achieve CR to subsequent CAR-T and remains in prolonged remission despite multiple relapsed/refractory disease. It is unknown if this patient's positive outcome was impacted by the effect of nivolumab on T cells and/or related to slower disease kinetics as this pt had a 3 month period between dMRD and radiographic detection and long duration of response to prior lines. A larger study is needed to adequately assess impact of early intervention MN using MRD kinetics, particularly in patients receiving CAR-T. All pts with dMRD had radiographic relapse within 4 months of molecular relapse. No pts with uMRD by ctDNA had clinical relapse on study during 2 year follow up, confirming uMRD correlates with disease free survival. If a strong negative predictive value is confirmed in a larger study, ctDNA MRD testing may be used to spare pts from imaging or to guide additional work up in pts with inconclusive findings on scans.

Introduction: Diffuse Large B-cell Lymphoma (DLBCL) are aggressive B-cell non-Hodgkin lymphomas (NHL). One particular subtype, Primary Mediastinal B-cell Lymphoma (PMBCL), is often grouped with DLBCL, but it possesses distinct biological and clinical characteristics. While initial therapy successfully cures approximately two-thirds of patients (pts), those who do not respond or experience progression within the first two years have a poor prognosis despite novel cellular therapies and bispecifics and ultimately succumb to their disease. There is a pressing need for more effective therapeutic approaches in this patient population. Recent advances in the understanding of DLBCL pathogenesis have led to the targeting of various signaling pathways, including the PI3K-AKT-mTOR pathway. One such drug, copanlisib (C), a pan-PI3K inhibitor with potent PI3K-α/PI3K-δ inhibition, exhibited activity in both indolent and aggressive NHL. In preclinical studies using a DLBCL mouse model, treatment with C effectively reduced the immunosuppressive tumor-infiltrating T-regulatory cells (Tregs). Moreover, when combined with a surrogate anti-mouse programmed death -1 (PD-1) blocker, C demonstrated significant in vivo responses (75%) compared to the monotherapy groups (0%). These findings support the rationale for exploring the combination of nivolumab, a PD-1 blocker, and copanlisib (C-N) in DLBCL. Thus, a phase 2 prospective study has been developed, focusing on two relapsed/refractory (RR) cohorts (DLBCL and PMBCL), treated with the combination of C-N. A prespecified interim analysis was planned upon enrollment of 14 pts. Herein, we report outcomes of the 12 enrolled pts, as the study was halted prematurely due to a safety signal deemed possibly related to the combination. Study design: C 60 mg was given intravenously on days 1, 8, and 15 during cycles 1-8, and on days 1 and 15 in subsequent cycles. N 240 mg IV was given on days 1 and 15 during cycles 1-8, and 480 mg on day 1 on subsequent cycles. Each treatment cycle is 28 days. Therapy was given for up to 2 years, as long as there is no disease progression or unacceptable side effects. The primary objective of the study is to determine the ORR, which includes complete and partial responses (CR+PR). Secondary objectives include evaluating the safety of the combination, as well as assessing progression-free survival (PFS), duration of response (DOR), CR, and overall survival (OS). The study plan was to enroll a maximum of 106 pts, including a safety cohort of 6 pts. The study received funding from Bayer and conducted through NCI-CTEP (NCI Protocol #10193; NCT03484819). Results: Twelve pts who received at least one cycle of C-N were included in this analysis. Pt characteristics are illustrated in table 1. All enrolled pts had DLBCL histology. Only one patient received a prior autologous stem cell transplant. Interestingly 4/12 received prior chimeric antigen receptor T-cell therapy (CART). Of the 12 enrolled pts, seven were evaluated for response. The ORR was 25% (3/12) (95% CI: 5 - 57%), all CR. The median number of cycles received was 2.5 (range 1-24) with two pts receiving 23 and 24 cycles. Observed grade 3 and higher adverse events (AEs) were as follows: non-hematologic AEs in 10/12 (83.3%), while hematologic AEs were seen in 5/12 (41.7%) pts. A relatively higher incidence of cardiac events (4/12) were noted including one cardiac arrest after one cycle of therapy, and four atrial fibrillation events, all grade 3, but only two were deemed possibly attributed to therapy. The cardiac arrest was deemed unrelated to therapy. Conclusions: C-N combination had modest clinical activity in pts with R/R DLBCL with some prolonged responses. However, due to the relatively high number of cardiac events and the changing therapeutic landscape with recent approvals, a decision was made to halt the study. These findings likely reflect possibly older and sicker patient population. Biomarker studies for predictors of response are under consideration.

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma in the United States with high biological complexity and multiple discrete subtypes, identified by detailed gene expression and sequencing studies [1,2]. Despite this heterogeneity, anthracycline-based chemoimmunotherapy, such as RCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone), remains the standard of care for most patients with newly diagnosed DLBCL [3,4]. Patients with primary refractory DLBCL have limited treatment options and often dismal prognosis, and require newer, more effective treatment options [5]. CD30, a diagnostic hallmark of classical Hodgkin lymphoma (cHL), is expressed in 14% of DLBCL cases [6]. Brentuximab vedotin (BV), an anti CD30 monoclonal antibody conjugated to the small-molecule microtubule disrupting agent monomethyl auristatin E (MMAE), is FDA approved for the treatment of cHL [7]. While its biological and prognostic implications are unclear in DLBCL [6,8], CD30 may represent a viable therapeutic target for BV, in this disease, although data on this topic are extremely limited [9]. Another potential target for DLBCL therapy is the programmed death (PD-)1/PD-ligand (L)1 axis. PD-L1 expression has been reported in almost all patients with cHL, but only a fraction of those with DLBCL [10]. Nivolumab (NIVO), a human IgG4 anti-PD-1 monoclonal antibody, has shown remarkable results in patients with relapsed/ refractory (R/R) cHL and it is currently approved (as are other PD-1 blockers) for this indication [11]. It has, however, only modest activity in patients with R/R DLBCL, possibly due to the low frequency of alterations of 9p24.1 (where the PD-L1 and PD-L2 genes reside) in this population [10]. The term DLBCL with Hodgkin features refers to a distinctive subgroup of aggressive lymphomas with clinical and pathological features reminiscent of both DLBCL and cHL [12], thus BV and NIVO may represent attractive treatment options for this entity. Herein, we present the case of a patient with DLBCL with cHL-like features, primarily refractory to multiple lines of therapy, including chimeric antigen receptor (CAR)-T cells, who was successfully treated with combined BV and NIVO. A 56-year-old man presented to our clinic with persistent fatigue, bloating, lack of appetite, drenching night sweats, unintentional weight loss, and palpable lymphadenopathy. Lab work was notable for a hemoglobin of 8.5 g/dL. Biopsies of an inguinal enlarged lymph node and a rib lesion revealed large cells expressing CD20, PAX5 (strong), BCL6, MUM1, MYC, p53, CD30, and BCL2. FISH showed translocation of BCL2, but no rearrangements of cMYC or BCL6. A PET scan revealed multiple FDG-avid lymph nodes above and below the diaphragm, bilateral subpleural nodules, bone lesions, and mildly FDG-avid splenomegaly (Figure 1(A)). A staging bone marrow biopsy additionally showed a CD10-positive, t(14;18)-positive B-cell population, suggesting that the DLBCL had arisen in the context of underlying follicular lymphoma. The patient was diagnosed with stage IV DLBCL, germinal center B-cell subtype with an international prognostic index of 2, and was treated with RCHOP. An interim positron emission tomography (PET)computer tomography (CT) scan after four cycles suggested progression of disease (POD) in the right chest wall (Figure 1(B)), subsequently confirmed by biopsy of the lesion. The patient began salvage therapy with rituximab, dexamethasone, cytarabine, and oxaliplatin (RDHAX) and a post-cycle 2 PET-CT scan showed further POD (Figure 1(C)). The patient was treated with third-line axicabtagene ciloleucel, utilizing bendamustine, rituximab (BR) and polatuzumab as a bridging therapy. Of note, a PET-CT performed after one cycle of BR-polatuzumab showed further POD. The post-CAR-T therapy course was complicated by grade 2 cytokine release syndrome treated with tocilizumab and grade 3 immune effector cell-associated neurotoxicity syndrome requiring dexamethasone, anakinra, and a brief intensive care unit admission. A day þ28 PET-CT again raised concern for

Highlights • Biomarkers of response to ibrutinib + nivolumab were analyzed in diffuse large B-cell lymphoma (DLBCL), follicular lymphoma and Richter transformation.• DLBCL patients with elevated PD-L1 by immunohistochemistry tended to have better response and survival.• Whole exome sequencing identified gene mutations in alternate B-cell receptor pathways linked to response in DLBCL.• Enriched pathways by gene expression profiling were related to immune activation in responders and proliferation/replication in nonresponders.• This preliminary work may help to generate hypotheses on genetically defined subsets of patients most likely to benefit from ibrutinib + nivolumab.

Autologous hematopoietic stem cell transplantation (ASCT) is a standard-of-care treatment for many hematologic malignancies. Progression of disease after ASCT is the primary cause of treatment failure. In this Phase Ib trial, we studied the safety and clinical effect of combined checkpoint inhibition therapy (CPIT) with ipilimumab and nivolumab as a consolidation strategy after ASCT for patients with high-risk diffuse large B cell lymphoma (DLBCL), mature T cell lymphoma (TCL), and multiple myeloma (MM). Starting at 14 to 28 days after ASCT, patients received ipilimumab (1 mg/kg i.v. on day 1 of weeks 1, 4, 7, 10, 16, and 22) and nivolumab (3 mg/kg i.v. on day 1 of weeks 1, 4, 7, 10, 12, 14, 16, 18, 20, 22, 24, and 26). Patients received a median of 5 doses of ipilimumab and 8 doses of nivolumab. Thirty-five patients were included in the intent-to-treat population. Ninety-four percent of the patients experienced immune-related adverse events (irAEs) of any grade. Ninety-seven percent of irAEs resolved spontaneously or after holding study drugs and instituting high-dose corticosteroid therapy. Progression-free and overall survival at 18 months post-ASCT for each disease cohort were 85.7% and 100% for primary refractory DLBCL, 28.6% and 57.1% for relapsed DLBCL, not evaluable and 80% for frontline TCL, 25% and 75% for relapsed TCL, 57.1% and 87% for high-risk transplant-naïve MM, and 40% and 100% for MM relapsed within 3 years of first ASCT. We conclude that combined CPIT appears to be tolerable as a consolidation strategy after ASCT and in addition to the potential clinical efficacy observed in some subsets of disease, T cell receptor repertoire, T regulatory cell phenotype, and gut microbiota profiles provide a biologic rationale warranting further study of this approach.

Purpose: Diffuse large B-cell lymphoma (DLBCL) patients need an accurate and early risk stratification strategy, as prompt therapy escalation may improve outcomes. Cell-free DNA (cfDNA) is an emerging liquid biopsy biomarker that has demonstrated clinical utility in guiding cancer treatment. Patients and Methods: We evaluated cfDNA genomic and fragmentomic features in 190 patients with large B-cell lymphoma from two multicenter prospective trials using Whole Genome Sequencing (WGS). Patients had a DLBCL or high-grade B-cell lymphoma (HGBL) diagnosis and were treated with R-CHOP or dose-adjusted EPOCH-R (followed by nivolumab consolidaiton for HGBL after achieving remission). Responders were defined as those in radiographic remission at the end-of-treatment (EOT) or those with a negative biopsy following a positive scan. Non-responders were defined as those with EOT PET-CT Deauville 4-5, progression, or death due to lymphoma during treatment. We extracted four cfDNA features: enhanced tumor fraction, proportion of short cfDNA fragments ranging from 20-150bp, the fragment end integrated analysis (FrEIA) score, and the Gini Diversity Index. We trained a Random Forest model with the training cohort (n = 120), performing hyperparameter optimization using 4-fold cross-validation to maximize prediction accuracy. We then evaluated the model's performance in the validation cohort (n = 61), averaging the ACT scores from the five models for classification predictions. We defined a new metric called the ACT score (Aberrations, Contribution of short fragments, Terminal motif analyses), where a threshold of 0.5 differentiates non-responders (ACT score ≥ 0.5) from responders. We evaluated the prognostic value of the ACT score for progression-free survival (PFS) and overall survival (OS), and in the context of IPI and interim PET-CT. Results: Individual cfDNA features were altered between responders and non-responders after one cycle of treatment, and the ACT score could predict EOT response (AUC 0.70). Patients with a positive ACT score had inferior outcomes compared to ACT score-negative patients [PFS: HR 3.2 (95% CI 1.4-7.2); p < 0.01; OS: HR 4.4 (95% CI 1.7-11.6); p < 0.01]. The 2-year PFS in ACT score-positive and -negative patients was 40% vs. 80%; and OS was 55% vs. 90%, respectively. In the multivariate analysis, the prognostic value of the ACT score was independent of the International Prognostic Index and interim PET-CT. Conclusions: The ACT score, computed from a single plasma sample collected after one cycle of treatment, can predict clinical outcomes. This low-cost and easy-to-interpret tumor-naïve test has the potential to guide treatment in interventional clinical trials and risk-adapted treatment strategies.

No abstract available

While the Epstein–Barr virus (EBV) is known to drive de novo lymphomagenesis, it may rarely contribute to transformation of indolent lymphoma as well. Some EBV-related lymphomas represent a diagnostic challenge with important prognostic and therapeutic implications. We describe a case of follicular lymphoma (FL) transformation to both EBV + diffuse large B-cell lymphoma (DLBCL) and EBV + classic Hodgkin lymphoma (cHL), the latter of which was only identified retrospectively after selective outgrowth during DLBCL therapy. Finally, we describe successful salvage therapy with brentuximab vedotin plus nivolumab. This is the first known case of composite lymphoma with FL, EBV + DLBCL, and EBV + cHL within a single lymph node. The disease course highlights the importance of careful morphologic examination and comprehensive immunophenotypic characterization of EBV + lymphomas to ensure proper clinical care and underscores the potential for novel therapies currently under investigation. This trial is registered with NCT01671813.

A 63-year-old man was diagnosed with stage IV-B DLBCL with bone marrow (BM) infiltration. He had double-hit lymphoma and Ki67 was 90%. Two cycles of a dose-adjusted rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin (R-EPOCH) regimen were given with clinical and radiologic improvement. However, lymphomatous skin lesions confirmed by cytologic examination developed. Computerized tomography (CT) scans showed progressive disease. In the original biopsy sample, PD-L1 expression was detected in 30% of lymphoma cells. A rituximab-vinorelbine-gemcitabineprednisolone regimen was given for two cycles as secondline treatment. However, rapid progression developed and an ibrutinib-nivolumab combination was planned and prescribed. Four days after ibrutinib treatment, WBC and lymphocyte/ monocyte counts increased rapidly and peaked at 100x109/L on the 20th day of treatment. Mononuclear cells were larger than mature lymphocytes with nucleolus-like bodies. Flow cytometric surface analysis showed CD10: 96%, HLA-DR: 55.8%, cCD79a: 53.6%, CD45: 100%, CD19: 13%, CD20: 0% expression. Nivolumab was given on the 14th day of ibrutinib treatment. CT scans showed regression of abdominal lymph nodes. However, febrile complication developed and he died due to infection.

Diffuse large B-cell lymphoma (DLBCL), with approximately 150,000 new cases worldwide each year, represent nearly 30% of all cases of non-Hodgkin lymphoma (NHL) and are phenotypically and genetically heterogeneous. A gene-expression profile (GEP) has identified at least three major subtypes of DLBCL, each of which has distinct clinical, biological, and genetic features: activated B-cell (ABC)-like DLBCL, germinal-center B-cell (GCB)-like DLBCL, and unclassified. Different origins are associated with different responses to chemotherapy and targeted agents. Despite DLBCL being a highly heterogeneous disease, more than 60% of patients with DLBCL can be cured after using rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) to inhibit the growth of cancer cells while targeting the CD20 receptor. In recent decades, the improvement of diagnostic levels has led to a refinement classification of DLBCL and the development of new therapeutic approaches. The objective of this review was to summarize the latest studies examining genetic lesions and therapies for DLBCL.

Currently, there is no definitive and effective treatment strategy for relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL). In recent years, studies on brentuximab vedotin (BV) and programmed cell death-1 (PD-1) monotherapy for R/R DLBCL have demonstrated significant clinical benefits. Based on this, this article retrospectively analyzes a case of R/R DLBCL with secondary hemophagocytic syndrome successfully treated with BV combined with a PD-1 monoclonal antibody and reviews the relevant literature. The patient was a 55-year-old woman who was diagnosed with stage IIE diffuse large B-cell lymphoma in June 2020. She failed to achieve complete remission during first-line treatment with the R-CHOP (rituximab, cyclophosphamide, doxorubicin/epirubicin, vincristine, and prednisone) regimen. After switching to the R2-GDP regimen for second-line salvage therapy, her condition continued to progress, and recurrent hemophagocytic syndrome developed. Subsequent treatment with BV combined with a PD-1 monoclonal antibody resulted in significant relief of her symptoms. As of the follow-up on 8 March 2025, the patient maintained a normal life and had no intolerable immune-related adverse effects. This study suggests that BV combined with PD-1 monoclonal antibody may exert a synergistic effect in the treatment of R/R DLBCL complicated with hemophagocytic lymphohistiocytosis (HLH).

Aim To evaluate the therapeutic value and find out potential combination agents of programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) monoclonal antibody (mAb) in relapsed/refractory (r/r) diffuse large B-cell lymphoma (DLBCL). Methods We conducted a meta-analysis to assess the efficacy and safety of PD-1/PD-L1 mAb in r/r DLBCL, potential qualified studies were searched in PubMed, Embase, Web of Science, and ClinicalTrials.gov. This meta-analysis had been registered on the PROSPERO platform (CRD42023340031). Results After systematic screening, a total of 32 records involving 29 studies were included, pooled survival curves indicated better progression-free survival (PFS) (p < 0.0001; HR = 0.51, 95% CI [0.42–0.62]) and overall survival (OS) (p = 0.013; HR = 0.71, 95% CI [0.57–0.88]) for combination therapy compared with monotherapy. Combination therapy group also achieved a better pooled complete response rate (CRR) (14.6% vs. 3.0%; p < 0.001) and overall response rate (ORR) (30.5% vs. 10.3%; p < 0.001). Analysis of the incidence of adverse events (AEs) did not demonstrate additional toxicities of combination therapy. The limitation was the predominance of single-arm trials, precluding the direct comparison of combination versus partner agents alone. Conclusions These findings support further exploration of PD-1/PD-L1-mAb-based combination therapy to identify long-term survival benefits, while application of monotherapy in unselected DLBCL patients is not recommended.

Abstract This article conducts a meta-analysis to evaluate the safety and efficacy of PD-1/PD-L1 inhibitors in patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL). A total of 63 papers were initially retrieved, and eight clinical studies were collected. The estimated effect of ORR was [OR = 0.40, 95% CI 0.29–0.51; p = 0.08], the estimated effect of complete response rate was [OR = 0.21, 95% CI 0.14–0.31; p < 0.001], while the estimated effect of 1-year progression-free survival was [OR = 0.33, 95% CI 0.22–0.47; p = 0.01]. The estimated effect of 1-year OS was [OR = 0.67, 95% CI 0.55–0.77; p = 0.05]. In addition, the estimated effect of grade 3 adverse events was [OR = 0.33, 95% CI 0.22–0.46; p = 0.01]. Overall, PD-1/PD-L1 inhibitors demonstrated suboptimal therapeutic efficacy in the selected trials for R/R DLBCL. However, combining PD-1/PD-L1 inhibitors with CAR-T showed potential for improved treatment outcomes. Additionally, PD-1/PD-L1 inhibitors were found to be safe and well-tolerated in patients with R/R DLBCL.

Patients with relapsed/refractory (r/r) diffuse large B-cell lymphoma (DLBCL) show varied responses to PD-1 monoclonal antibody (mAb) containing regimens. The mechanisms and predictive biomarkers for the efficacy of this regimen are unclear. This study retrospectively collected r/r DLBCL patients who received PD-1 mAb and rituximab regimens as salvage therapy. Clinical and genomic features were collected, and mechanisms were explored by multiplex immunofluorescence and digital spatial profiling. An artificial neural network (ANN) model was constructed to predict the response. Between October 16th, 2018 and May 4th, 2023, 50 r/r DLBCL patients were collected, 29 were response patients and 21 were non-response patients. CREBBP (p = 0.029) and TP53 (p = 0.015) alterations were statistically higher in non-response patients. Patients with PD-L1 CPS ≥ 5 were correlated with a longer overall survival (OS) than those with PD-L1 CPS < 5 (median OS: not reached vs. 9.7 months, hazard ratio [HR]: 3.8, 95% confidence interval [CI] 0.64–22.44, p = 0.016). Immune-related pathways were activated in response patients. The proportion and spatial organization of tumor-infiltrating immune cells affect the response. PD-L1 CPS level, age, and alterations of TP53, MYD88, CREBBP, EP300, GNA13 were used to build an ANN predictive model that showed high prediction efficiency (training set area under curve [AUC] of 0.97 and test set AUC of 0.94). The proportion and spatial distribution of tumor-infiltrating immune cells may be related to the function of immune-related pathways, thereby influencing the efficacy of PD-1 mAb containing regimens. The ANN predictive model showed potential value in predicting the responses of r/r DLBCL patients received PD-1 mAb and rituximab regimens.

Introduction: High-dose immunochemotherapy followed by autologous hematopoietic stem cell transplantation (auto-HSCT) is the second-line treatment protocol for relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL). However, certain patients might be unsuitable for transplantation due to age-related factors or comorbidities. Therefore, we designed this trial (ChiCTR2200056256) to evaluate the efficacy and safety of a chemotherapy-free regimen combining lenalidomide, programmed cell death-1 (PD-1) monoclonal antibody, and orelabrutinib for the treatment of R/R DLBCL. Methods: This multicenter, open-label, single-arm, phase II study was conducted at eight hospitals in China. Patients were eligible if they met the diagnostic criteria for R/R DLBCL, and were aged 18-85 years with an Eastern Cooperative Oncology Group performance status of 0-1. Patients received lenalidomide (10-25 mg/d, oral, day 1-10), PD-1 monoclonal antibody (200 mg, IV, day 1), and orelabrutinib (150 mg/d, oral). The dose adjustment of lenalidomide was required according to the patient's blood routine. The primary endpoint was the overall response rate (ORR). The key secondary endpoints included complete remission (CR) rate, progression-free survival (PFS), and safety. Results: From August 2021 to March 2024, 34 patients were enrolled. Seventeen patients were aged 60 years or older, with a male-to-female ratio of 1:1.4. Twelve (35.3%) patients were IHC-CD5 positive at the time of diagnosis. Besides, 28 (82.4%) patients had a history of cardiovascular and hypertensive disease. Enrolled patients received a total of 148 cycles of treatment, with a median cycle of 4 (range, 1-8). At the end of cycle 3, 5 (14.7%) patients achieved CR, 26 (76.5%) patients achieved partial response (PR), resulting in an ORR of 91.2%, and 3 patients had progressive disease (PD). By the cutoff date (March 25, 2024), ORR was 70.6%, with 11.8% (4/34) CR and 58.8% (20/34) PR. Regarding different biomarker subgroups, the ORR was 81.8% (18/22) for CD5-negative, 50% (6/12) for CD5-positive, 50% (7/14) for Ki67 ≤75%, and 85% (17/20) for Ki67 >75%. Additionally, for patients with ≤3 treatment cycles, the ORR was 50% (6/12); for >3 cycles, it reached 81.8% (18/22). At a median study follow-up of 17.0 months, the median PFS and overall survival (OS) were not reached. The estimated 24-month duration of remission, PFS, and OS rates were 70.7% (95% CI, 56.3-88.8), 64.6% (95% CI, 50.3-82.9), and 81.9 (95% CI, 69.8-96.1), respectively. In addition, the median time to remission was 2.4 months. Subgroup analysis revealed that patients with CD5-negative, Ki67 >75%, number of treatment cycles >3, and efficacy achieved PR and CR showed improved PFS (P=0.009, P=0.006, P=0.029, and P <0.001, respectively). Additionally, patients with Ki67 >75%, non-B symptoms, and efficacy achieved PR and CR had better OS (P=0.03, P=0.033, and P <0.001, respectively). Univariate analysis showed that CD5-positive (HR, 4.365; 95% CI, 1.306-14.590; P=0.017) and Ki67>75% (HR, 0.191; 95% CI, 0.051-0.711; P=0.014) were factors associated with inferior PFS. Multivariate analysis revealed that the numbers of extra-nodal sites at baseline (HR, 3.032; 95% CI, 1.013-9.070; P=0.047) and B symptoms (HR, 6.468; 95% CI, 1.082-38.642; P=0.041) were predictors of inferior PFS. Adverse events (AEs) were observed in 20 (58.8%) patients, with the most common hematologic AEs being anemia and thrombocytopenia (both grade 1). Three patients developed severe anemia, 1 patient developed a grade 3 rash, and 1 patient developed a first-degree atrioventricular block, but no malignant arrhythmic events were observed. At the data cutoff (March 25, 2024), five deaths occurred. Conclusion: This study evaluated the efficacy and safety of a chemotherapy-free regimen combining the novel BTKi (orelabrutinib), PD-1 monoclonal antibody, and lenalidomide in R/R DLBCL. The findings indicated that this triple-drug combination, which targeted multiple mechanisms, synergistically exerted potent anti-tumor effects and demonstrated effectiveness with favorable tolerability in R/R DLBCL.

Immunochemotherapy has demonstrated a promising efficacy for a variety of B-cell lymphoma but has limited efficacy for Epstein–Barr virus-positive (EBV +) diffuse large B-cell lymphoma (DLBCL) that is refractory or relapsed to conventional chemotherapy regimens. Considering higher programmed death-ligand 1 (PD-L1) expression in the subset of patients with DLBCL with positive EBV, we speculated that PD-1 inhibitors plus chemotherapy may be an alternative regimen in patients with refractory/relapsed EBV + DLBCL. This retrospective study included six adult patients diagnosed with refractory EBV + DLBCL resistant to first-line immunochemotherapy regimens (R-CHOP). These patients received PD-1 inhibitors plus chemotherapy as second-line treatment. The final analysis included six patients (four men and two women (median age, 50 years; range, 39–83 years)). Four patients were diagnosed with Epstein–Barr virus (EBV) + DLBCL, and two had DLBCL associated with chronic inflammation. Over a median follow-up of 20 months (range, 2–31 months), the objective response rate was 83% (5/6) and the complete remission rate was 67% (4/6). No severe immune-related adverse reactions occurred, and only a mild rash was reported, which did not necessitate the discontinuation of therapy. The combination of PD-1 inhibitors and chemotherapy offers promising results as a second-line treatment for patients with refractory EBV + DLBCL that is resistant to first-line immunochemotherapy regimens. These preliminary findings warrant further investigation in larger clinical trials to validate the efficacy and safety of this therapeutic approach.

No abstract available

Patients with relapsed/refractory diffuse large B‐cell lymphoma (r/r DLBCL) have poor outcomes and few treatment options. We report the preliminary results of the efficacy and safety of PD‐1 monoclonal antibody (mab) plus Rituximab for r/r DLBCL.

The tumour microenvironment (TME), which is modulated after immune‐chemotherapy, is involved in tumour growth and metastasis. Programmed cell death 1 (PD‐1) expressed on tumour‐infiltrating non‐malignant cells plays an important role in the TME through the PD‐1/programmed cell death ligand 1 (PD‐L1) signalling pathway. However, its impact in patients with relapsed or refractory (R/R) diffuse large B‐cell lymphoma (DLBCL) remains unclear.

Background: Glofitamab, an innovative CD20xCD3 bispecific T-cell engager, has emerged as a groundbreaking therapeutic option for relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL), receiving FDA approval for patients who have failed ≥2 prior lines of therapy. This immunotherapeutic agent mediates potent antitumor activity by redirecting endogenous T cells to eliminate CD20-expressing malignant B cells, demonstrating remarkable clinical efficacy even in high-risk subgroups. Current evidence remains insufficient regarding glofitamab's efficacy in primary refractory and early relapsed (≤12 months post-first-line therapy) DLBCL - clinically distinct subgroups characterized by particularly aggressive disease biology and critically unmet therapeutic needs Methods: This real-world study include glofitamab in 12 DLBCL patients (primary refractory n=9; early relapsed n=3) receiving planned 12-cycle therapy. Glofitamab was combined with polatuzumab vedotin, PD-1 inhibitors, GemOx, BTKi, or radiotherapy per clinical practice. Primary endpoints included overall response rate (ORR) and complete response (CR) rate by Lugano criteria. Secondary endpoints assessed progression-free survival (PFS), duration of response (DOR), and CRS/ICANS graded by ASTCT criteria. Mechanistic analyses included serial immune profiling of T/NK-cell subsets and serum cytokine monitoring. Results: At the data cut-off (July 25, 2025), among 12 treated patients (median 5 cycles, range 1–12), 75% (9/12) were primary refractory and 25% (3/12) early relapsed. Histologic/molecular subtypes included DLBCL DEL (58.3%, 7/12), DLBCL NOS (16.7%, 2/12), HGBCL (8.3%, 1/12), CD5+ DLBCL (8.3%, 1/12), and TP53-mutated (16.7%, 2/12). Median age was 56 years (range 37–79); 91.7% (11/12) had stage III/IV disease, with median IPI 3 (41.7% IPI 3, 33.3% IPI 4).All were heavily pretreated (median 3 prior lines, range 2–7; 83.3% Pola-exposed, 16.7% CAR-T–experienced). At median 7.0-month follow-up (range 1.0–16.5), evaluable patients (9/12) demonstrated 100% ORR and 55.5% CMR (median time: 2 cycles). CMR rates were 57.1% in primary refractory (4/7) and 50% in early relapsed disease (1/2), with subtype-specific responses noted. The safety profile remained consistent with prior analyses. Grade ≥3 AEs occurred in 58.3% (7/12) of patients. Dose interruptions of glofitamab were required in 50% (4/12) (due to CRS [n=1] and pulmonary infections [n=3]), with 8.3% (1/12) discontinuing due to pulmonary infection. Median dose intensity was maintained at 100% for GEMOX and POLA.Cytokine release syndrome (CRS) occurred in 33.3% (4/12) (Gr 3, n=1), all during Cycle 1 (no ICANS reported). Tocilizumab was administered in 8.3% (1/12). Neurologic AEs (NAEs) were reported in 83.3% (10/12) (Gr 3/4, n=7), most commonly neutropenia (83.3%), hypoalbuminemia (58.3%), frailty (58.3%), low immunoglobulinemia (58.3%), anemia (41.7%), and pulmonary infection (25.0%). Grade 3 NAEs included neutropenia (58.3%), pulmonary infection (16.7%), and CRS (8.3%). This study analyzed immune function changes during 12 treatment cycles. Early treatment cycles (1-6) were associated with modest declines in immunoglobulin levels (IgG/IgM/IgA) and low infection risk. Beyond cycle 6, severe lymphopenia (lymphocytes <0.5×10⁹/L) emerged in 33.3% (4/12), correlating with increased pulmonary infections, necessitating vigilant monitoring. Glofitamab induced robust T/NK-cell expansion, with 91.7% (11/12) showing elevated CD3+/CD4+/CD8+/NK-cell counts. Clinically meaningful expansions (>1-fold) occurred in 50.0% (6/12) for CD3+/CD4+/NK cells and 58.3% (7/12) for CD8+ cells. Notably, this activation persisted without exhaustion through 6 cycles, including in CAR-T–pretreated (n=2) and bendamustine-exposed (n=2) subgroups, suggesting sustained modulation of the tumor immune microenvironment. Conclusions: Glofitamab exhibits clinically significant activity in primary refractory and early relapsed DLBCL through potent T/NK-cell engagement, inducing durable responses across high-risk subtypes. Real-world data support combinability with Polatuzumab Vedotin, PD-1 immune checkpoint inhibitor, GemOx, BTKi, or radiotherapy, warranting proactive toxicity monitoring. These findings establish glofitamab as a transformative backbone therapy for resistant DLBCL, addressing critical unmet needs via its unique immune-redirecting mechanism.

More than 40% of patients diagnosed with diffuse large B-cell lymphoma (DLBCL) eventually develop relapsed or refractory (r/r) disease and typically have poor outcomes. Autologous chimeric antigen receptor T-cell therapy (CART) has emerged as a crucial second line treatment option for r/r DLBCL, but 60-70% of patients still relapse or are refractory. Recent research has shed light on the role of TP53 alterations (mutation or deletion) in r/r DLBCL patients who do not respond well to CART cell therapy. The findings in this study will show that the combination of CART with PD-1 inhibitors (ICIs) had a significant impact on the efficacy and prognosis of r/r DLBCL patients with TP53 alterations. This retrospective analysis included adult DLBCL patients who were treated at Shanghai Tongji Hospital of Tongji University with autologous CD19 (N=20) or CD20 (N=2, patient 6 and 7, Fig.1 A) CART-cell therapy between January 1, 2019, and September 30, 2022. All enrolled patients provided their informed consent to participate in the study. The protocol of the study was reviewed and approved by the Institutional Review Board of the National Cancer Institute, ensuring ethical practices were followed. A total of 22 patients with TP53 alterations undergoing CD19-CART therapy were included, of which 2 patients received CD20 CART cell after recurrence of CD19 CART cell therapy. The total dose of CD19 or CD20-CAR T-cell is between 1- 3x10^6/kg. Sintilimab/Tislelizumab was used as PD-1 inhibitors (3 mg/kg in patients weighing <60 kg or 200 mg in patients weighing ≥60 kg) every three weeks within 6 weeks after CAR-T infusion. 1 case had grade 3-4 Cytokine Release Syndrome (CRS) and no case had CART-cell-related encephalopathy syndrome (CRES). In Table 1, the patients are divided into two groups. One group received CART cells combined with PD-1 inhibitors (ICI+), while the other group received CART cells only (ICI-). The median ICIs treatment time after CART infusion was 17 days (IQR 11-38 days). Baseline factors such as age, gender, disease severity, previous treatment history and etc. had no substantial differences between the groups. Treatment regimen and the subsequent response were shown in Fig.1 A and B. Patient 1-9 received ICIs treatment after CART cell therapy, of which 8 cases (88.9%) showed the best objective response rate (ORR) at day 90 after CART infusion (Fig.1B) and 6 cases (66.7%) achieved complete remission (CR). In comparison, among the 13 individuals who were treated with CART alone, only 3 cases (23.1%) showed the best ORR at day 90 after CART infusion and only 1 case (7.7%) achieved complete remission. We found a significant difference between the two treatment groups by performing a Chi-square test (P=0.009). Our results suggest that the addition of PD-1 inhibitors to the CART regimen significantly improves the treatment outcome in patients with TP53 alterations. In Fig.1 C and D, we show that the median progression-free survival (PFS) was NR (not reached) vs. 1.7 months (95% CI:1.0 month-2.3 months) and the median overall survival (OS) was NR vs.10.9 months (95% CI: 3.8 months-18.1 months) in the ICI+ and the ICI- groups. The p-values for PFS and OS was 0.001 (HR=0.18, 95% CI: 0.07-0.47) and 0.003 (HR=0.15, 95% CI: 0.05-0.42) between the two groups. These results suggest that patients in the combination treatment group experienced less disease progression and were more likely to survive longer. Overall, our study demonstrates the potential benefits of combining immunotherapies, specifically CART with PD-1 inhibitors, in the treatment of relapsed or refractory DLBCL patients with TP53 alterations.

Background: Chimeric antigen receptor (CAR) T-cell therapy has proven to be a standard of care (SOC) for patients with relapsed/refractory B-cell lymphoma (R/R B-NHL).Nevertheless, a substantial subset of patients fails to achieve sustained remission with CD19-targeted CAR-T therapy. While CAR-T cell efficacy is known to be influenced by multifactorial determinants, the association between T-cell exhaustion markers (e.g., Programmed cell death protein 1[PD-1]) and clinical outcomes remains incompletely characterized in current studies. Aims: We aimed to explore the correlation between the ratio of circulating PD-1+CAR-T cells to those in the infusion product and the efficacy of CAR-T cell therapy in R/R B-NHL. Methods: From July 2022 to November 2024, 129 patients who received CD19 CAR T-cell therapy from Beijing GoBroad Hospital were enrolled.The median age was 52(23-75)years old.Diagnoses included DLBCL NOS (n=112), PMBCL(n=5) ,tFL(n=7), and BL (n=5). In the primary cohort, 114/129 (88.4%) patients were at stage III-IV at the time of salvage therapy. The median IPI score was 3 (range 2-5). 46/129 (35.7%) patients had central nervous system violations. 48/129(37.2%)patients had>7cm bulky disease and 14/129(10.9%)patients failure of prior autologous hematopoietic stem cell transplantation (HSCT).In order to further reduce the tumor burden, 61/129(47.3%) patients were treated with bridging therapy before CAR-T cell infusion. Using spectral flow cytometry, we analyzed the CAR-T cell product and post-infusion samples collected on days 7, 14, and 28 from each patient, with specific focus on calculating the ratio of circulating PD-1+CAR-T cells to their counterparts in the infusion product (designated as the circulating-to-product [C/P] ratio). The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were used to compare the accuracy of each C/P ratio in predicting complete remission (CR) rate at 3 months. The value corresponding to the maximum Youden index was selected as the optimal cut-off value. The optimal cutoff values of C/P ratio at days 7, 14 and 28 after infusion were 2.049, 2.629 and 2.241, respectively. The C/P ratio were transformed into binary predictors based on the optimal cut-off values, and univariate logistic regression analyses were performed to assess the association between C/P ratio predictors and the CR rate at 3 months. Survival curves were plotted using the Kaplan–Meier method to calculate the survival rate, and the log-rank test was carried out to compare the survival outcomes between groups. Results There were 90/129(69.8%) patients achieve CR at 3 month after CAR T infusion. The median follow-up time was 13.15 (range 10.92-18.97) months.The 2-year progression-free survival (PFS) was 71.57%(95% CI:62.57,78.77)and overall survival (OS) was 81.66%(95% CI:72.53,88.00)for the overall population, respectively. We found that patients with C/P ratio higher than the optimal cutoff value had significantly improved PFS and OS. At day 7 post-infusion, the high C/P ratio group showed superior PFS [2-year 76.62%(95% CI: 62.45-86.02) vs. 55.72%(95% CI:35.55-71.84); P=0.046] and OS [2-year 84.69%(95% CI: 70.26-92.48) vs. 68.49%(95% CI:47.35-82.57); P=0.035]. These benefits were further amplified by day 28, with the high C/P ratio group maintaining significantly better PFS[2-year 89.74%(95% CI: 74.94-96.02) vs. 71.25%(95% CI:51.88-83.94); P=0.044]and OS [2-year 97.14%(95% CI:81.40-99.59)vs.82.53%(95% CI:62.27-92.51); P=0.039], demonstrating the prognostic value of C/P ratio levels following CAR-T cell infusion. The 2-year PFS was higher in high C/P ratio group [77.84%(95% CI: 64.87-86.50) vs. 67.15%(95% CI:50.52-79.27); P=0.282], and the 2-year OS was also higher in high C/P ratio group [83.44%(95% CI: 70.32-91.11)vs.81.93%(95% CI: 65.91-90.91); P=0.640]on days 14 after infusion. However, these differences were not statistically significant. Conclusion: Our longitudinal analysis revealed that the circulating-to-product (C/P) ratio of PD-1+ CAR-T cells—calculated by comparing their frequency in peripheral blood at days 7 and 28 post-infusion to baseline levels in the manufactured product—served as a robust early predictor of durable disease control.A high PD-1+CAR-T C/P ratio strongly correlated with improved clinical outcomes such as response and progression-free survival.

Background: Patients with relapsed or refractory (R/R) aggressive B-cell lymphomas, particularly diffuse large B-cell lymphoma (DLBCL), have a poor prognosis. Glofitamab, a CD20xCD3 bispecific antibody, has demonstrated significant efficacy in pivotal clinical trials. However, a pressing need exists for real-world evidence on its effectiveness and safety, especially within heavily pre-treated and heterogeneous patient populations. This study aimed to evaluate the outcomes of glofitamab-based therapy in a real-world cohort of Chinese patients with R/R aggressive B-cell lymphomas and to identify predictive factors for response. Methods: This retrospective, multicenter study enrolled 65 patients with R/R aggressive B-cell lymphoma treated with glofitamab-based regimens. We collected baseline demographic, clinical, and treatment data. The majority of patients received glofitamab as monotherapy (50.8%) or in combination with PD-1 inhibitors (27.7%). Primary efficacy endpoints were the overall response rate (ORR) and complete response (CR) rate. Survival outcomes, including progression-free survival (PFS) and overall survival (OS), were analyzed using the Kaplan-Meier method. Safety was evaluated based on reported adverse events (AEs). Univariate logistic regression analyses were performed to identify predictors for achieving a CR. Results: A total of 65 patients were included in the analysis. The cohort was characterized by high-risk features: 72.3% were older than 60 years, 80.7% had Ann Arbor stage III-IV disease, the median treatment line 4 (range 2-11), and 50.9% had refractory disease. The predominant histology was DLBCL (83.1%), with 67.2% being of the non-germinal center B-cell (non-GCB) subtype. Among 43 efficacy-evaluable patients, the best ORR was 67.4% (95% CI: 51.5%-80.9%), with a CR rate of 46.5%. For the 39 patients in the survival analysis, the median follow-up was 5.88 months (95% CI: 4.24-9.86). The median progression-free survival (PFS) was 6.0 months (95% CI: 4.3-NA) , and the median overall survival (OS) was 13.9 months (95% CI: 12.5-NA). The treatment was well-tolerated, with the most frequent grade ≥3 AEs being anemia (18.2%), neutropenia (15.9%), and leukopenia (13.6%). Cytokine release syndrome (CRS) occurred in 18.2% of patients, and was predominantly low-grade. Severe, grade ≥3 CRS was observed in only 4.5% of patients. Univariate analysis revealed that relapsed disease (vs. refractory, OR=5.06, p=0.020) and the absence of bone marrow involvement (OR=4.44, p=0.039) were associated with a higher likelihood of achieving CR.Conclusion: In this multicenter, real-world study of Chinese patients with R/R aggressive B-cell lymphoma, glofitamab-based therapy demonstrated substantial efficacy, achieving high response rates and promising survival outcomes. At the same time, the safety profile was predictable and manageable, with a low incidence of severe CRS. Our findings suggest that glofitamab is a valuable therapeutic option for this challenging patient population. Disease status (relapsed vs. refractory) and bone marrow involvement were factors significantly associated with complete response in univariate analysis, warranting further validation.

Introduction: Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (Br J Haematol 2024;205(6):2163-2174). Although first-line treatment with R-CHOP achieves remission in a substantial proportion of patients, many ultimately develop relapsed or refractory (R/R) disease. Currently, therapeutic options for these patients remain limited, particularly for those who are ineligible for stem cell transplantation (J Clin Oncol 2014;32(10):1066-73; Blood 2022;140 Suppl:12089). Tafasitamab is a humanized, Fc-enhanced monoclonal antibody targeting CD19 (Blood 2024;143(3):258-271); it has been approved in combination with lenalidomide for the treatment of adults with R/R DLBCL, representing the first second-line therapy approved for this patient population (Drugs 2020;80(16):1731-1737). However, real-world evidence regarding the effectiveness and safety of tafasitamab-containing regimens, particularly with novel combinations incorporating radiotherapy (RT) or PD-1 inhibitors, is scarce in the Chinese population. This case series characterizes the clinical outcomes of tafasitamab-containing therapies in routine clinical practice. Methods: We retrospectively analyzed five consecutive R/R DLBCL patients (median age 81 years, range 50-87) with poor baseline PS (ECOG ≥2: 3/5 patients; ECOG 3: 1 patient) and high tumor burden treated between Jan 2024-Jul 2025. All were heavily pretreated (median prior lines: 4; range 2-7) and transplant-ineligible. Tafa combinations included RT (n=1) or PD-1 inhibitors (tislelizumab, n=2). Outcomes included clinical response (Lugano 2014) and safety (CTCAE v5.0). Results: Cohort Vulnerability: Patients exhibited high-risk features: advanced age (≥80 years: n=3), ECOG ≥2 (n=3), high IPI (≥3: n=2), double-expressor lymphoma (n=2), bone marrow involvement (n=2), and pre-existing infection (n=1). Five patients (P1-P5) were included, with details as follows: P1: 81-year-old female with stage IVA germinal center B-cell (GCB) DLBCL (ECOG 2). After 4 prior therapies with partial response (PR), she achieved stable disease with tafasitamab + lenalidomide after 2 cycles, with only grade 1 leukopenia and grade 2 thrombocytopenia. P2: 87-year-old female with stage IIB non-GCB DLBCL (ECOG 2, IPI 3, MYC/BCL2 double expression). Uncontrolled after 4 prior regimens, she achieved PR with tafasitamab + lenalidomide + radiotherapy + zanubrutinib (maintained through cycle 3), but she had pre-existing pulmonary infection, recurrent infections, and grade 4 neutropenia. Subsequent treatment consisted of a regimen combining tafasitamab and adoptive NK cell-based immunotherapy, and progressed in cycle 4 after switching regimens. P3: 68-year-old male with stage IVB non-GCB DLBCL (ECOG 0, IPI 2). After partial metabolic response to first-line therapy, he achieved a complete response (CR) with tafasitamab + lenalidomide after 1 cycle, with no treatment-related adverse events (TRAEs). P4: 82-year-old female with stage IVB non-GCB DLBCL (ECOG 3, IPI 5, MYC/BCL2 double expression). Previously treated with ZRD, she received tafasitamab with no TRAEs; treatment was ongoing at analysis, with response unassessed. P5: 50-year-old female with stage IVB non-GCB DLBCL (transformed from mucosa-associated lymphoid tissue lymphoma; ECOG 0, IPI 2). She achieved CR with tafasitamab + lenalidomide + tislelizumab after 2 cycles, maintaining remission for 6 additional cycles with no TRAEs over 8 total cycles. These patients had an advanced average age of 81 years (range: 50-87), with 80% at stage IV and generally poor baseline status. However, in real-world practice, flexible tafa-len-based combinations (including PD-1 inhibitors, radiotherapy, or BTK inhibitors) yielded favorable outcomes (best ORR: 75%, CR rate: 50%), with good overall safety. Progression-free survival was maintained in 80% (4/5) of patients during the follow-up period. Conclusion: This real-world series demonstrates that tafa-containing regimens exhibit clinically meaningful activity in extremely frail, heavily pretreated R/R DLBCL patients with poor baseline PS (ECOG ≥2 in 80%). Critically, combinations incorporating radiotherapy or PD-1 inhibition (tislelizumab) yielded significant responses. These novel combinations warrant prospective investigation in high-risk, poor-PS R/R DLBCL populations where effective, tolerable therapies are urgently needed.

Primary central nervous system lymphoma (PCNSL) is a highly aggressive central nervous system lymphoma that has a high relapse rate and a 5-year survival rate of 30%-40% with conventional treatment. In about 95% of cases, Primary Central Nervous System Diffuse Large B-cell Lymphoma (PCNS-DLBCL) occurs. In some patients, the tumor microenvironment exhibited high levels of PD-L1, which may be linked to prognosis. The key mechanism for PD-L1 overexpression in EBV- tumor cells is the amplification of the 9p24.1 copy number, with signaling pathways such as JAK2 and NF-κB possibly playing a role in this process. Immune checkpoint inhibitors (anti-PD-1/PD-L1 mAb), particularly combined with BTK inhibitors, show promise in relapsed/refractory PCNSL. Still, there is no universally accepted therapeutic consensus. The blood-brain barrier limits drug penetration, and the spatiotemporal heterogeneity of PD-L1 remains a challenge. This paper discusses the expression of PD-L1 in PCNS-DLBCL and its relationship to prognosis, the efficacy of anti-PD-1 mAb and other drugs, and possible predictive markers of efficacy to provide a basis for anti-PD-1/PD-L1 mAb therapy, and the future of targeted PD-L1 therapy to achieve a high remission rate and individualized immunotherapy for PCNSL patients.

Disease relapse remains the leading cause of failure after autologous stem cell transplantation (ASCT) for patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL). We conducted a phase 2, multicenter, single-arm study of the anti-PD-1 monoclonal antibody pembrolizumab given after ASCT in patients with chemosensitive DLBCL, hypothesizing that it would improve the progression-free survival (PFS) at 18 months after ASCT (primary endpoint) from 60% to 80%. Pembrolizumab was administered at 200 mg IV every 3 weeks for up to 8 cycles, starting within 21 days of post-ASCT discharge. Twenty-nine patients were treated on this study; 62% completed all 8 cycles. Seventy-nine percent of patients experienced at least one grade 3 or higher adverse event, and 34% experienced at least one grade 2 or higher immune-related adverse event. Overall, 59% of patients were alive and progression free at 18 months, which did not meet the primary endpoint. The 18-month overall survival was 93%. In conclusion, pembrolizumab was successfully administered as post-ASCT consolidation in patients with R/R DLBCL, but the PFS did not meet the protocol-specific primary objective and therefore does not support a larger confirmatory study. This trial was registered at www.clinicaltrials.gov as #NCT02362997.

Refractory or relapsed diffuse large B-cell lymphoma (DLBCL) often associates with the activated B-cell-like (ABC) subtype and genetic alterations that drive constitutive NF-κB activation and impair B-cell terminal differentiation. Here, we show that DNA damage response by p53 is a central mechanism suppressing the pathogenic cooperation of IKK2ca-enforced canonical NF-κB and impaired differentiation resulting from Blimp1 loss in ABC-DLBCL lymphomagenesis. We provide evidences that the interplay between these genetic alterations and the tumor microenvironment select for additional molecular addictions that promote lymphoma progression, including aberrant coexpression of FOXP1 and the B-cell mutagenic enzyme activation-induced deaminase, and immune evasion through major histocompatibility complex class II downregulation, PD-L1 upregulation, and T-cell exhaustion. Consistently, PD-1 blockade cooperated with anti-CD20-mediated B-cell cytotoxicity, promoting extended T-cell reactivation and antitumor specificity that improved long-term overall survival in mice. Our data support a pathogenic cooperation among NF-κB-driven prosurvival, genetic instability, and immune evasion mechanisms in DLBCL and provide preclinical proof of concept for including PD-1/PD-L1 blockade in combinatorial immunotherapy for ABC-DLBCL.

Background CD5-positive (CD5+) non-germinal center B-cell-like diffuse large B-cell lymphoma (non-GCB DLBCL) is heterogeneous with a poor prognosis. For refractory DLBCL, the median overall survival was only 6.3 months. Therefore, there is a need for approaches to elongate the survival in this subgroup of relapsed DLBCL patients. Case Description Here, we present a rare case of a 72-year-old patient with stage IV CD5+ non-GCB DLBCL with myeloid differentiation primary response 88 (MYD88) and cluster of differentiation 79B (CD79B) comutations. Zanubrutinib and rituximab therapy was initially administered until disease progression. Subsequently, zanubrutinib plus rituximab together with attenuated standard chemotherapy (miniCHOP) was applied and a notable response was observed. The patient tolerated the treatment well and exhibited a complete response in lung for about 5 months. Afterwards, the patients experienced relapse in the brain and started programmed death protein 1 (PD-1) regimens of toripalimab plus lenalidomide, which also exhibited a good response with decreased lesions in brain after half-year treatment. However, the patient experienced relapse again in the brain 3 months later and started chemotherapy with methotrexate plus rituximab. The patient had survived for over 2 years since the initial diagnosis of stage IV DLBCL and has continued to survive after experiencing a relapse in the brain for approximately 11 months till now. Conclusions These findings suggest that toripalimab may be a new therapeutic option for central nervous system recurrence in refractory CD5+ DLBCL with MYD88 and CD79B comutation. Further clinical trials are warranted to confirm these results.

Patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) transformed from indolent B-cell lymphomas, including Richter transformation, have a poor prognosis. PD-1/PD-L1 antibodies produce modest objective and complete response rates in B-cell non-Hodgkin lymphoma as monotherapy but may synergize with immunogenic chemotherapies such as gemcitabine and oxaliplatin (GemOx). Thus, we evaluated the safety and efficacy of atezolizumab plus rituximab and GemOx (R-GemOx+Atezo) in R/R transformed DLBCL, including Richter transformation. We conducted a phase I trial including patients with transformed DLBCL after ≥1 prior therapy. Patients received up to four cycles of R-GemOx+Atezo. Patients in complete remission could then proceed to R-Atezo maintenance until progression. A safety lead-in with evaluation of dose-limiting toxicity was performed to confirm the recommended phase II dose; subsequently the treatment was administered to two expansion cohorts: one with transformed follicular lymphoma (FL) and the other with non-FL transformed DLBCL, including Richter transformation. Twenty-seven patients were enrolled. One of the six patients in the safety lead-in had a dose-limiting toxicity attributed to atezolizumab, a grade 4 Stevens-Johnson syndrome. The most common grade ≥3 events were neutropenia (18.5%), lymphopenia (18.5%), and thrombocytopenia (14.8%). The overall and complete response rates were 59% and 33%, respectively. The overall and complete response rates in transformed FL were 79% and 43%, respectively, and 38% and 23% in transformed non-FL, respectively. The median progression-free survival and overall survival of the total population were 4.2 and 7.7 months, respectively. R-GemOx+Atezo was well tolerated and demonstrated promising preliminary efficacy in patients with relapsed/refractory transformed DLBCL.

Abstract Background Diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS) is the most common type non-Hodgkin’s lymphoma, where the treatment of relapsed/refractory cases is the major challenge. Programmed cell death protein 1 (PD-1) and its ligand PD-L1 play a crucial role in the negative regulation of the immune response against the disease. The aim of the study was to analyze the expression of PD-1 and PD-L1 on lymphoma cells (LCs) and tumor-immune cells (TICs) and to investigate their correlation with outcome. Patients and methods Samples from 283 patients diagnosed with DLBCL, NOS (both germinal center B cell like [GCB] and non-GCB subtypes) were included in the study. Expression of PD-1 and PD-L1 was determined using double immunohistochemical staining (D-IHC) for PD-1/PAX5 and PD-L1/PAX5 on tissue microarrays. LCs were highlighted by D-IHC to obtain more accurate results. Clinical data and histologic diagnoses were obtained from electronic data records. We correlated clinical characteristics, and PD-1 and PD-L1 expression on LCs and TICs with progression-free survival (PFS) and overall survival (OS). Results Expression of PD-1 on TICs was observed in 38.4% and on LCs in 8.8% of cases, while PD-L1 was expressed on TICs in 46.8% and on LCs in 6.5% of cases. PD-L1 expression on LCs was more frequent in non-GCB subtype (p = 0.047). In addition, patients with PD-L1 expression on LCs had significantly shorter PFS (p = 0.015), and the expression retained significant in the multivariate model (p = 0.034). Conclusions PD-L1 was more frequently expressed in LCs of the non-GCB subtype. Additionally, PD-L1 in LCs may predict shorter PFS time. D-IHC staining for PD-L1/PAX5 is a feasible method to assess PD-L1 expression on LCs of DLBCL, NOS patients and can be used to identify patients who may benefit from targeted immunotherapy with checkpoint inhibitors.

Patients with relapsed or refractory lymphoma have limited treatment options, requiring newer regimens. In this Phase 1/2 study (NCT03769181), we assessed the safety, efficacy, and pharmacokinetics of isatuximab (Isa, anti‐CD38 antibody) in combination with cemiplimab (Cemi, anti‐programmed death‐1 [PD‐1] receptor antibody; Isa + Cemi) in patients with classic Hodgkin lymphoma (cHL), diffuse large B‐cell lymphoma (DLBCL), and peripheral T‐cell lymphoma (PTCL). In Phase 1, we characterized the safety and tolerability of Isa + Cemi with planned dose de‐escalation to determine the recommended Phase 2 dose (RP2D). Six patients in each cohort were treated with a starting dose of Isa + Cemi to determine the RP2D. In Phase 2, the primary endpoints were complete response in Cohort A1 (cHL anti‐PD‐1/programmed death‐ligand 1 [PD‐L1] naïve), and objective response rate in Cohorts A2 (cHL anti‐PD‐1/PD‐L1 progressors), B (DLBCL), and C (PTCL). An interim analysis was performed when the first 18 (Cohort A1), 12 (Cohort A2), 17 (Cohort B), and 11 (Cohort C) patients in Phase 2 had been treated and followed up for 24 weeks. Isa + Cemi demonstrated a manageable safety profile with no new safety signals. No dose‐limiting toxicities were observed at the starting dose; thus, the starting dose of each drug was confirmed as the RP2D. Based on the Lugano 2014 criteria, 55.6% (Cohort A1), 33.3% (Cohort A2), 5.9% (Cohort B), and 9.1% (Cohort C) of patients achieved a complete or partial response. Pharmacokinetic analyses suggested no effect of Cemi on Isa exposure. Modest clinical efficacy was observed in patients with cHL regardless of prior anti‐PD‐1/PD‐L1 exposure. In DLBCL or PTCL cohorts, interim efficacy analysis results did not meet prespecified criteria to continue enrollment in Phase 2 Stage 2. Isa + Cemi did not have a synergistic effect in these patient populations.

Checkpoint blockade therapy (CBT) has revolutionised the management of some malignancies in recent years, leading to long-term remissions, initially with advanced-stage malignant melanoma. More recently, improvements in outcomes have been seen in a wide range of solid tumours including nonsmall-cell lung cancer (NSCLC) and notably Hodgkin lymphoma. In contrast to these practice-changing results, clinical outcomes following CBT in non-Hodgkin lymphoma (NHL) have been disappointing, with overall response rates of ≤10% and median progression-free survival of <2 months with programmed cell death protein 1 (PD-1) blockade in relapsed and refractory diffuse large B-cell lymphoma (DLBCL). This lack of clinically meaningful efficacy has led many haemato-oncologists to conclude that CBT is unlikely to play a significant role in the management of NHL. Although the reasons underlying the poor clinical responses seen with CBT in NHL are currently far from clear, there are likely to be two broad mechanistic areas underlying these treatment failures. First, due to an inability to induce cognate anti-tumour T-cell responses due to either a lack of recognition of tumour antigenicity or failure of tumour antigen presentation; second, pre-existing anti-tumour immunity may be overcome by suppressive immune effector cells and the cytokine milieu within the tumour microenvironment. In this issue of the British Journal of Haematology, Carreau et al. describe the outcomes of treatment beyond failure of CBT for NHL. In a cohort of 60 patients with NHL treated predominantly with agents blocking PD-1 or its ligand, PD-L1, they observe that the duration of response (DOR) for postCBT therapy was longer than the DOR with preceding lines of treatment, prior to CBT. It is usually assumed that increasing lines of therapy will result in decreasing response rates and DOR. Given that the trend was reversed in this study, with longer DOR to therapy after CBT, the authors argue that CBT may sensitise patients to subsequent treatments. These provocative data are certainly hypothesis-generating and provide an opportunity to re-evaluate how we approach the use CBT in NHL, as a potential ‘sensitiser’ to chemotherapy, rather than as a single agent in refractory disease. However, before concluding from this intriguing data that CBT has a clear role in sensitising patients with refractory NHL to further chemotherapy or targeted agents, it is important to outline some of the caveats that undermine the ability to draw firm conclusions. Patients have been selected on account of a lack of durable response to prior therapies, so it is perhaps unsurprising that pre-CBT DOR was short. Furthermore, those patients with the most rapidly progressive disease during CBT may be ineligible for further treatment and absent from this analysis. Patients were also highly heterogeneous in terms of histology and pre/post-CBT treatment. However, the findings in this study of NHL are in agreement with similar retrospective analyses performed in other malignancies, including Hodgkin lymphoma. Encouragingly, they are also supported by preclinical studies demonstrating synergy between selected chemotherapy agents and CBT. The authors discuss how CBT might interact with the tumour and its microenvironment to enhance the efficacy of subsequent treatments. The ability of many cancer therapies to stimulate anti-tumour immunity has long been recognised, but the extent to which this influences clinical outcomes is underexplored and largely unknown. We know that radiation therapy (RT), doxorubicin and many other agents are able to induce a type of tumour cell death known as immunogenic cell death (ICD). ICD results in the generation of an inflammatory environment that activates antigen Correspondence: Elizabeth H. Phillips, Division of Cancer Sciences, University of Manchester, Manchester, UK. E-mail: beth.phillips@manchester.ac.uk commentary

Chimeric antigen receptor (CAR) T cell therapy has demonstrated exceptional efficacy in treating hematologic malignancies. However, clinical outcomes can be limited by factors such as suboptimal expansion and persistence of adoptively transferred CAR-T cells, antigen-negative relapses, and the immunosuppressive tumor microenvironment. In our previous work, we engineered CD19CAR-T cells to secrete a PD-1Ab21 fusion protein, which combines an anti-PD-1 single-chain antibody with IL-21 (PD-1Ab21-CD19CAR-T). This investigator-initiated clinical trial aims to evaluate the safety and therapeutic potential of these novel CAR-T cells in patients with relapsed/refractory B-cell non-Hodgkin lymphoma (r/r B-NHL). The study has recruited 9 patients with r/r B-NHL, with additional patient enrollment ongoing. All patients received fludarabine and cyclophosphamide before a single infusion of PD-1Ab21-CD19CAR-T cells, with escalating dose ranging from 0.3×106 to 3×106 cells/kg. Patients were monitored for adverse events, clinical responses, and immune cell kinetics, including the expansion of CAR-T cells and CD8+ T cells. Nine patients were enrolled, with a median age of 61 years (range: 38-73). One patient had follicular lymphoma (FL), and the remaining eight were diagnosed with diffuse large B-cell lymphoma (DLBCL), two of whom had bone marrow involvement. The overall response rate (ORR) was 77.8% (7/9), with 66.7% (6/9) achieving complete remission (CR). Cytokine release syndrome (CRS) occurred in 55.6% (5/9) of patients, but all cases were very mild (grade ≤1). No treatment-related neurotoxicity or deaths were reported. The first patient, diagnosed with DLBCL and presenting with paraplegia, achieved CR three months after CAR-T infusion, which has been sustained for over two years, resulting in a progression-free survival (PFS) greater than two years. After CAR-T infusion, we observed a rapid increase in CAR-CD8+ T cell proportion, which remained above 50% even after the decline of CAR-T cells. These preliminary findings suggest that PD-1Ab21-CD19CAR-T cells have promising clinical efficacy in r/r B-NHL, with a high ORR and sustained CR. The mild nature of CRS (grade ≤1) indicates that this treatment can be well tolerated. Further studies are necessary to confirm these results and assess long-term outcomes. Yu Jing, Ying Li, Meng Li, Shengjuan Zhang, Baocai Zhao, Yueyi An, Hang Li, Jitao Zhao, Liping Dou, Shengdian Wang. Phase I investigator-initiated clinical trial of CD19CAR -T cells secreting PD-1-targeted IL-21 in relapsed/refractory B-cell non-Hodgkin lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT144.

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The programmed death-ligands, PD-L1 and PD-L2, reside on tumor cells and can bind with programmed death-1 protein (PD-1) on T-cells, resulting in tumor immune escape. PD-1 ligands are highly expressed in some CD30+ large cell lymphomas, including classic Hodgkin lymphoma (CHL), primary mediastinal large B-cell lymphoma (PMBL), Epstein–Barr virus (EBV)-positive diffuse large B-cell lymphoma (EBV+ DLBCL), and anaplastic large cell lymphoma (ALCL). The genetic alteration of the chromosome 9p24.1 locus, the location of PD-L1, PD-L2, and JAK2 are the main mechanisms leading to PD-L1 and PD-L2 overexpression and are frequently observed in these CD30+ large cell lymphomas. The JAK/STAT pathway is also commonly constitutively activated in these lymphomas, further contributing to the upregulated expression of PD-L1 and PD-L2. Other mechanisms underlying the overexpression of PD-L1 and PD-L2 in some cases include EBV infection and the activation of the mitogen-activated protein kinase (MAPK) pathway. These cellular and molecular mechanisms provide a scientific rationale for PD-1/PD-L1 blockade in treating patients with relapsed/refractory (R/R) disease and, possibly, in newly diagnosed patients. Given the high efficacy of PD-1 inhibitors in patients with R/R CHL and PMBL, these agents have become a standard treatment in these patient subgroups. Preliminary studies of PD-1 inhibitors in patients with R/R EBV+ DLBCL and R/R ALCL have also shown promising results. Future directions for these patients will likely include PD-1/PD-L1 blockade in combination with other therapeutic agents, such as brentuximab or traditional chemotherapy regimens.

Aims: Mediastinal gray zone lymphoma (MGZL) is a rare entity with morphologic, immunophenotypic, and genetic features intermediate between classic Hodgkin lymphoma (CHL) and primary mediastinal large B-cell lymphoma (PMBL). It is challenging to differentiate from CHL and PMBL. A specific dendritic cell gene expression profile can distinguish CHL and MGZL from PMBL. We hypothesized that the dendritic markers fascin and CD123 may be helpful in distinguishing MGZL from CHL and PMBL. We also investigated programmed death-ligand 1 (PD-L1) expression in MGZL, which may have therapeutic significance in this difficulty to treat tumor. Methods: Representative sections from 89 CHL, 20 PMBL, and 7 MGZL cases were stained for fascin, CD123, and PD-L1, and scored on a scale from 0 to 3+. Most (71%) MGZLs stained for CD123, as well as some (23%) CHLs, and few (11%) PMBLs. All MGZLs stained for fascin, as well as most (90%) CHLs, and approximately half (53%) of the PMBLs. PD-L1 was positive in all MGZLs, most (77%) CHLs and most (66%) PMBLs. Conclusions: Our study is the first to show CD123 is positive in a subset of formalin-fixed, paraffin-embedded MGZLs and CHLs, in contrast to PMBL which is largely negative. Staining for fascin was not significantly different between the lymphomas, but was less likely to be positive in PMBL. These findings suggest a role for CD123 and fascin in supporting diagnoses of MGZL and CHL, and in ruling out PMBL. By immunohistochemistry, PD-L1 is positive in MGZL, pointing to its therapeutic potential.

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Background: Mediastinal gray zone lymphoma (MGZL) is a rare B-cell lymphoma characterized by overlapping clinicopathologic and molecular features of primary mediastinal B-cell lymphoma (PMBL) and classical Hodgkin lymphoma (CHL). Under current WHO-HEMA5 and International Consensus Classification (ICC) frameworks, MGZL is restricted to EBV-negative lymphomas arising in the mediastinum. Methods: This review summarizes current evidence on epidemiology, clinical presentation, pathology, molecular characteristics, diagnostic challenges, and therapeutic approaches to MGZL, with data derived from retrospective series, limited prospective cohorts, and recent molecular studies. Results: MGZL predominantly affects young adults and commonly presents with bulky mediastinal disease. Diagnosis is challenging due to transitional morphology, pleomorphic Reed–Sternberg-like cells, and variable expression of B-cell and activation markers. Molecular studies demonstrate shared alterations with PMBL and CHL, including 9p24.1 (JAK2/PD-L1/PD-L2) gains, while additional reported features such as HOXA5 hypomethylation and MYC copy number gains support its biological distinctiveness, although evidence remains limited. Frontline treatment commonly involves intensive chemoimmunotherapy regimens such as DA-EPOCH-R; however, outcomes remain inferior to PMBL and CHL, with 5-year overall survival rates of approximately 40–60%. Relapsed or refractory disease frequently requires salvage chemotherapy and autologous stem cell transplantation. Immune-based therapies, including brentuximab vedotin and PD-1 inhibitors, have shown promising activity, particularly in combination. Conclusions: MGZL remains a diagnostically challenging and therapeutically complex lymphoma with inferior outcomes compared with related mediastinal lymphomas. Advances in molecular profiling and immunotherapy offer promising avenues toward more personalized treatment; however, prospective clinical trials and international collaboration are urgently needed to establish evidence-based management strategies for this rare entity.

Primary extranodal diffuse large B‐cell lymphoma (PE‐DLBCL) is a heterogeneous subgroup of DLBCL. We investigated the prevalence and prognostic value of surface expression of PD‐L1, PD1, and CD30, copy number of 9p24.1 (PD‐L1 region), and mutations in MYD88, CD79B, CARD11, and BTK in a cohort of 116 patients, localized in the mediastinum (PMBL, n = 12), ear, nose and throat (ENT, n = 28), central nervous system (n = 29), testis (n = 7), breast (n = 4), stomach (n = 10), bone (n = 8), spleen (n = 2), and skin (n = 16). PD‐L1 expression is most frequent in PMBL (92%), followed by lymphomas originating in the stomach (57%), ENT (23%), and skin (18%). PD1 was expressed at low levels in less than 13% of PE‐DLBCL, while CD30 expression was found in 58% of PMBL. Mutation analysis revealed an unexpectedly high frequency of MYD88 and CD79B mutations in ENT lymphomas (46% and 50%, respectively). CARD11 mutations are rare but more frequently found in gastric lymphomas (30%), suggesting BTK resistance. Thirty‐four of 113 (30%) of the lymphomas harbored both MYD88 and CD79B mutations. Lower overall and progression‐free survival rates were found for cases with MYD88, CD79B, and BTK mutations. These data confirm the biologic singularity of PE‐DLBCLs and provide some suggestions for targeted therapies.

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The engagement of programmed cell death protein 1 (PD-1; encoded by the PDCD1 gene) receptor expressed on activated T cells and its ligand, programmed death-ligand 1 (PD-L1; encoded by the CD274 gene), is a major co-inhibitory checkpoint signaling that controls T cell activities. Various types of cancers express high levels of PD-L1 and exploit PD-L1/PD-1 signaling to evade T cell immunity. Blocking the PD-L1/PD-1 pathway has consistently shown remarkable anti-tumor effects in patients with advanced cancers and is recognized as the gold standard for developing new immune checkpoint blockade (ICB) and combination therapies. However, the response rates of anti-PD-L1 have been limited in several solid tumors. Therefore, furthering our understanding of the regulatory mechanisms of PD-L1 can bring substantial benefits to patients with cancer by improving the efficacy of current PD-L1/PD-1 blockade or other ICBs. In this review, we provide current knowledge of PD-L1 regulatory mechanisms at the transcriptional, posttranscriptional, post-translational, and extracellular levels, and discuss the implications of these findings in cancer diagnosis and immunotherapy.

BACKGROUND PD-L1 expression and tumor mutational burden (TMB) have emerged as important biomarkers of response to immune checkpoint inhibitor (ICI) therapy. These biomarkers have each succeeded and failed in predicting responders for different cancer types. We sought to describe the PD-L1 expression landscape across the spectrum of ICI-responsive human cancers, and to determine the relationship between PD-L1 expression, TMB, and response rates to ICIs. METHODS We assessed 9887 clinical samples for PD-L1 expression and TMB. RESULTS PD-L1 expression and TMB are not significantly correlated within most cancer subtypes, and they show only a marginal association at the tumor sample level (Pearson's correlation 0.084). Across distinct tumor types, PD-L1 expression and TMB have nonoverlapping effects on the response rate to PD-1/PD-L1 inhibitors and can broadly be used to categorize the immunologic subtypes of cancer. CONCLUSION Our results indicate that PD-L1 expression and TMB may each inform the use of ICIs, point to different mechanisms by which PD-L1 expression regulates ICI responsiveness, and identify new opportunities for therapeutic development. FUNDING Funding was provided by Foundation Medicine Inc., the Johns Hopkins Bloomberg-Kimmel Institute for Cancer Immunotherapy, the Viragh Foundation, the National Cancer Institute Specialized Program of Research Excellence (SPORE) in Gastrointestinal Cancers (P50 CA062924), the NIH Center Core Grant (P30 CA006973), the Norman & Ruth Rales Foundation, and the Conquer Cancer Foundation.

Primary mediastinal large B-cell lymphoma (PMLBCL) is an aggressive B-cell malignancy that may exhibit resistance to standard chemoimmunotherapy. Novel immunotherapeutic strategies, including checkpoint inhibitors and chimeric antigen receptor T-cell (CAR-T) therapy, are being explored in cases that are refractory to treatment. We report the case of a 29-year-old patient with refractory PMLBCL who was treated with pembrolizumab as a bridging therapy followed by axicabtagene ciloleucel (CAR-T) after failing R-CHOP and R-DHAP regimens. Initial disease progression following pembrolizumab was consistent with an immune-related flare phenomenon. Subsequent CAR-T infusion led to a complete metabolic response. Immunologic monitoring revealed expansion of CD3+ and CD56+ lymphocyte subsets, suggesting immune activation. Notably, the patient maintained normal endocrine function and conceived spontaneously three years post-treatment, delivering a healthy infant at term. This case highlights the potential synergy between checkpoint inhibition and CAR-T cell therapy in refractory PMLBCL, providing rare evidence of preserved fertility following intensive immunotherapy. Early recognition of immune flare and multidisciplinary management are critical in optimizing outcomes for young patients receiving novel immunotherapeutic approaches.

Key Points • In this analysis, checkpoint inhibitor therapy after CAR-T failure resulted in an overall response rate of 19% and median PFS of 54 days.• Patients with primary mediastinal B-cell lymphoma and with late relapse after CAR-T had improved outcomes to checkpoint inhibitor therapy.

Anti-CD19 chimeric antigen receptor (CAR) T cell therapy actually represents the standard of care for multiple relapsed or refractory primary mediastinal B-cell lymphoma (r/r PMBCL). Checkpoint inhibitors, such as pembrolizumab, appear to be a safe and effective treatment strategy for patients who are ineligible for or resistant to autologous stem cell transplantation. Although preclinical studies suggested that checkpoint inhibitors may enhance the vitality and anti-tumor activity of CAR T cells, there are no substantial/robust clinical data about the immune-mediated toxicity of their association. We describe a case of a severe cutaneous adverse event arising immediately after Cytokine Release Syndrome (CRS) on day +6 from CAR T cells infusion in a young r/r PMBCL patient who previously received pembrolizumab. These skin lesions were interpreted as an immune mediated adverse event, considering their prompt improvement and fully recovering achieved with the addition of immunoglobulin infusion to systemic steroid therapy. This case of life-threatening cutaneous adverse event calls for further investigations about off-target immune-related adverse events deriving from the combination of CAR T cell therapy and checkpoint inhibition, whose synergic therapeutic effect is promising.

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Background Amplification of 9p24.1 (9p) upregulates PDL-1/2 and JAK2, leading to an immune-privileged tumor microenvironment (TME) and lymphomagenesis. The 9p amplicon is a key driver of disease in related lymphomas found in 100% of Hodgkin Lymphoma (HL), and 75% of Primary Mediastinal B-cell lymphoma (PMBCL). We hypothesize that if overexpression of PDL-1/2 and JAK/STAT leads to immune escape and unchecked proliferation, then dual targeting with ruxolitinib (RUX, JAK2 inhibitor) and pembrolizumab (PEM, PD-1 inhibitor) will target complementary pathways and enhance immunogenicity, inducing cell death. Methods The IC50 values were established for RUX in four 9p positive (9p+) and negative (9p-) human lymphoma cell lines: K1106p (PMBCL, 9p+) 5.72 µM, L540 (HL, 9p+) 22 µM, Farage (PMBCL, 9p-) 29.46 µM, and U2940 (PMBCL, 9p-) 32.99 µM (Cell TiterGlo). To understand how RUX modulates markers of lymphomagenesis, western blot and flow cytometry was performed in all cell lines. Transcriptomic changes were evaluated by RNA-seq, presented as Log2 fold change compared to vehicle control. To understand the effects of combination treatment on T-cell infiltration and function within the TME, PMBCL and HL organoids were developed and treated with RUX (0.5uM, 2.5uM, 5uM) and PEM (10ug/mL), and compared to monotherapy and vehicle controls. Following co-culture with donor CD8+ T-cells, organoids were stained with fluorescent calcein (live), ethidium (apoptotic), and CD3+ dyes and imaged on Leica SP8-DLC. Mean fluorescent values were calculated by Fiji. Reserved organoids were analyzed for T-cell function/activation and apoptosis (flow cytometry). Preliminary in vivo experiments were completed with partially HLA-matched humanized mice (HuMice) xenografted with K1106p. Results The effect with RUX treatment was most prominent in 9p+ cell lines: 9p+ K1106p (n=5) demonstrated increased markers of immunogenicity: CIITA 4.83-fold (SEM ± 1.15) and MHCII 2.67-fold (SEM ± 0.33). Tumor suppressor SOCS1 increased 3.33-fold (SEM ± 0.68), and MYC decreased 8.58-fold (SEM ± 4.66). The 9p+ L540 (n=5) paralleled these findings. In all cell lines, with and without 9p, RUX reduced expression of PDL-1/2 (p < 0.01) and MYC (p<0.05), (n=4, for each cell line). In K1106p treated with RUX, RNA-seq showed increased lymphocyte differentiation (p < 0.001), immune response activating pathways (p = 0.003), increased MHCII (p=0.001), decreased PDL-1/2 (-1.04, p < 0.009), and decreased MYC (-0.95, p < 0.001). The 9p+ organoids (n=80) had the most significant decrease in live mean fluorescence with RUX+PEM compared to RUX alone (p=0.01) and to vehicle control (p=0.02). Intra-organoid T-cells (n=16) demonstrated increased CD3+ infiltration with RUX+PEM (p=0.01) compared to vehicle and monotherapy controls. There was significant decrease in intra-organoid PDL-1/2 ligands (p < 0.0001) with RUX treatment, suggesting a mechanism for synergy with RUX+PEM. Combination RUX+PEM demonstrated 43% reduction in total B-lymphocytes (p <0.001) with decreased live cells (p < 0.001) and increased dead cells (p=0.01) compared to vehicle and monotherapy controls (n=3). To confirm that RUX did not have a negative effect on T-cell viability and function, RUX treated T-cells demonstrated no change in live (p=0.71), dead (p=0.91), or apoptotic (p=0.6) T-cells, and no change in T-cell Ki-67 (p=0.78), granzyme-A (p=0.96), or granzyme-B (p=0.59), (n=3) compared to vehicle control. In K1106p HuMice, there was significant difference in tumor volume between control, and both treatment groups: RUX, and RUX+PEM (p=0.007, n=10), with stable weight (p=0.32) over 25 days of treatment. All drugs were safe and well tolerated. Doses have been optimized and there were no signs of graft vs. host disease in control or treated groups. Full in vivo studies will follow. Conclusion Altogether, these data suggest that RUX enhances immunogenicity and modulates lymphomagenesis primarily in 9p+ cell lines with increased CIITA, MHCII, and decreased MYC. In 9p+ organoids, combination treatment with RUX+PEM enhanced cell death via reduction in PDL-1/2 and increased T-cell infiltration. Deleterious effects of RUX on T-cell function were not observed. Full mouse model experiments are currently underway, laying the preclinical groundwork for a future clinical trial employing a multipronged approach for the treatment of 9p+ lymphomas. *Funded by ASH RTAF.

Background Primary Mediastinal B-cell Lymphoma (PMBCL) and Hodgkin Lymphoma (HL) are frequently defined by chromosome 9p24.1 amplification, leading to upregulation of PDL-1/-2 and JAK2. JAK2, in addition to its known role in the JAK/STAT pathway, has also been shown to act as an epigenetic modifier by phosphorylation of H3Y41, enabling an euchromatin state and expression of MYC. When these epigenetic modifications are coupled with upregulation of PDL-1/-2, the 9p amplicon leads to immune escape, unchecked cell proliferation, and tumorigenesis. We hypothesize that if deranged histone modification and amplified expression of PD-1 ligands cooperate to drive cell growth in 9p amplified PMBCL and HL, then dual targeting with JAK inhibitor and immune checkpoint blockade will lead to altered gene expression and enhanced immunogenicity inducing synergistic cell death. The following abstract demonstrates preliminary data using ruxolintib monotherapy in cell lines, with goal of combining immunotherapy in mouse models. Methods In order to understand how ruxolitinib modulates key drivers of lymphomagenesis in 9p24.1 amplified lymphoma, human lymphoma cell lines with 9p amplification, (n=2): Karpas1106p (PMBCL) and L540 (HL)were compared to cell lines lacking 9p24.1 amplification, (n=2): Farage (PMBCL) and U2940 (PMBCL). All samples were treated for 3- and 6-day intervals. The IC50 concentrations were established for ruxolintib using Cell TiterGlo assay: Karpas1106p 5.72 µM, L540 22 µM, Farage 29.46 µM, and U2940 32.99 µM. All cells were treated for 48 hours with control or ruxolitnib and probed by western blot, flow cytometry, and RNA-sequencing. The expression of key determinants of survival including JAK/STAT, pro- and anti-apoptotic proteins (SOCS1 and MYC, respectively) and MHCII were measured by western blot. PD-1/-2 ligands were measured by flow cytometry. Transcriptomic changes were evaluated by RNA-seq and data was presented as Log 2 fold change compared to vehicle controls. Results Pharmacodynamic effects were most prominent in the 9p amplified Karpas1106p cell line demonstrating increased markers of immunogenicity by protein quantification: increased CIITA by 3.5-fold (SEM ± 1.15) and increased MHCII by 2.67-fold (SEM ± 0.33). Expression of tumor suppressor SOCS1 was increased by 2.67-fold (SEM ± 0.68) and expression of oncogene MYC was decreased by 6.06-fold (SEM ± 4.66). The 9p amplified L540 line similarly demonstrated increased CIITA by 3.22-fold (SEM ± 1.59) and decreased MYC by 2.69-fold (SEM ± 0.65), however no significant change in MHCII or SOCS1 was observed. Significant reduction of STAT3p and/or STAT6p was demonstrated across all cell lines (p < 0.01). Cell lines without 9p amplification, Farage and U2940, did not demonstrate consistent increase nor decrease in markers of immunogenicity or oncogenes, suggesting ruxolitinib preferentially modulates downstream markers of survival and immune recognition driven by the 9p amplicon. Flow cytometry demonstrates significantly reduced expression of PDL-1 (p = 0.01) and PDL-2 (p = 0.001) in 9p amplified cell lines (Karpas1106p and L540), and non-amplified cell lines (Farage and U2940), as shown in Figure 1. Down-regulation of PDL-1/-2 was more prominent in the 9p amplified cell lines compared to those without 9p amplification (p = 0.055 and p = 0.18, respectively), suggesting that ruxolitinib may prime for increased immunogenicity by reducing PDL-1/-2, especially in 9p amplified cell lines. RNA-seq of the 9p amplified Karpas1106p cell line demonstrated increased MHCII: HLA-DQ (1.12, p < 0.001), HLA-DO (0.70, p < 0.001), HLA DM (0.14, p = 0.001), and decreased PDL-1 (-1.04, p < 0.009), PDL-2 (-1.70, p < 0.001), C-MYC (-0.95, p < 0.001), and STAT1/3/4 (all p < 0.001). Gene-ontology analysis demonstrated increased lymphocyte differentiation (p < 0.001) and immune response activating pathways (p = 0.003) ( Fig. 2). Conclusion Altogether, data suggests that ruxolitinib enhances immunogenicity primarily in 9p amplified cell lines and supports the hypothesis that ruxolitinib may prime for lymphoma cell death when combined with immunotherapy. These findings provide a foundation for in vivo assessment in humanized mouse models treated with combination anti-PDL-1 and JAK1/2 inhibitor, targeting tumorigenesis driven by 9p amplification. *This work has been funded by the ASH RTAF grant.

Treatment of cancer has transformed with the introduction of checkpoint inhibitors. However, the majority of solid tumor patients do not respond to checkpoint blockade. In contrast, the response rate to programmed cell death 1 (PD-1) blockade in relapsed/refractory classical Hodgkin lymphoma (cHL) is 65% to 84% which is the highest among all cancers. Currently, checkpoint inhibitors are only approved for cHL and primary mediastinal B-cell lymphoma as the responses to single-agent checkpoint blockade in other hematologic malignancies is disappointingly low. Various established biomarkers such as programmed cell death 1 ligand 1 (PD-L1) protein surface expression, mismatch repair (MMR) status, and tumor mutational burden (TMB) are routinely used in clinical decision-making in solid tumors. In this review, we will explore these biomarkers in the context of hematologic malignancies. We review characteristic 9p24.1 structural alteration in cHL and primary mediastinal B-cell lymphoma (PMBCL) as a basis for response to PD-1 inhibition, as well as the role of antigen presentation pathways. We also explore the reported frequencies of MMR deficiency in various hematologic malignancies and investigate TMB as a predictive marker.

Amplification of 9p24.1 (9p+) upregulates PDL-1/2 and JAK2, leading to an immune-privileged tumor microenvironment (TME) and lymphomagenesis. This biology is relevant for lymphomas that harbor 9p+ or rely on JAK/STAT and immune escape pathways for growth, including Hodgkin Lymphoma (HL) and primary B-cell mediastinal lymphoma (PMBCL). Our previous data suggest that ruxolitinib (RUXO), a JAK1/2 inhibitor, enhances immunogenicity by increasing CIITA, MHCII, and decreasing c-MYC in cell lines, while also increasing T-cell infiltration in lymphoma organoids, priming the TME for PD-1 inhibition with pembrolizumab (PEMBRO). We hypothesize that RUXO disrupts the immune-privileged TME by increased T-cell activation and immune surveillance, thereby increasing the efficacy of PEMBRO in 9p+ and JAK/STAT mutated lymphomas to enhance tumor death when combined with PEMBRO. To discern the effects of RUXO+PEMBRO on the peripheral immune milieu in patients, isolated peripheral blood mononuclear cells (PBMCs) were treated with vehicle, RUXO (1uM), PEMBRO (1mg/ml), or combination (COMBO); samples were analyzed by flow cytometry (HL = 7, PMBCL = 3). Compared to control, RUXO and COMBO increased peripheral immune surveillance via increased NK cells, decreased Tregs, and decreased immune suppressive myeloid derived suppressor cells (MDSCs) with all p<0.05; altogether suggesting an activated peripheral immune compartment. To investigate effects of RUXO+PEMBRO on tumor growth and survival, immunized BALB/c mice were engrafted with the syngeneic A20 cell line (JAK3, STAT 2/4 mutated). Mice (n=72) were treated with vehicle control, RUXO (90mg/kg), PEMBRO (5mg/kg every 4 days), or COMBO until tumor volumes>2000 mm3. A significant decrease in tumor volume was observed with COMBO compared to vehicle and monotherapy controls. With median follow up of 30 days, Kaplan-Meier analysis showed significant differences in median survival for COMBO (not reached) compared to vehicle (17 days), RUXO (23 days), and PEMBRO (25 days) with p<0.0001. Treatment was well tolerated and there was no significant decrease in weight. To understand the impact of RUXO+PEMBRO on the peripheral immune milieu, n=6 mice were sacrificed from each cohort on day 7 for PBMC analysis by flow cytometry. Immune activating effects via decreased MDSCs and increased NK cells were observed with COMBO compared to control. RUXO and COMBO increased markers of activation (CD25+) while decreasing markers of exhaustion (LAG3 and PD-1) in both CD4+ and CD8+ T-cells (all p <0.05). To understand the impact of RUXO+PEMBRO on the TME, humanized mice (huMice) partially HLA-matched to the human K1106p cell line (9p+) were treated with vehicle control, RUXO (30m/kg daily), PEMBRO (10mg/kg day 1, then 5mg/kg every 5 days), and COMBO; n=6 mice from each cohort were sacrificed at day 7 and analyzed by flow cytometry. PBMCs demonstrated increased markers of CD4+ and CD8+ T-cell activation (CD40L) with RUXO and COMBO. In tumor samples, RUXO and COMBO decreased PDL-1 expression. Tumor-infiltrating CD3+ T-cells were increased with RUXO and COMBO with increased markers of activation in CD4+ (CD40L) and CD8+ (CD40L, CD69) T-cells. A decreased CD4:CD8 ratio was observed in both PBMCs and tumor samples with RUXO and COMBO, shifting toward higher levels of activated CD8+ T cells. huMice tumor samples were further analyzed by spatial Multiomics Single-Cell Imaging (CosMx™) for protein tissue microarray. After QC, normalization, and scaling, five batch-correction methods (CLR, SCTransform, Harmony, BANKSY, InsituType) were compared. Cohorts demonstrated distinct treatment-specific remodeling of the TME with increased clusters of activated CD3⁺ T-cells, dendritic cells, plasmablasts, macrophages, and antigen-presenting B-cells. Specifically, COMBO (n=9) increased tumor-infiltrating activated macrophages, NK cells, and activated CD3+ T-cells compared to control (n=7). RUXO induces a shift toward an activated immune milieu, priming the 9+ TME for PEMBRO. RUXO+PEMBRO leads to synergistic anti-tumor activity, modulates the TME via increased infiltration of cytotoxic immune cells, and promotes a shift toward an activated CD8⁺ T cell-dominant TME. These data underscore the potential of JAK/PD-1 axis co-targeting to overcome immune evasion and enhance immunotherapeutic efficacy, leading to the development of an investigator-initiated trial in 9p+ and JAK/STAT mutated lymphomas.

Malignant cells are known to evade immune surveillance by engaging immune checkpoints which are negative regulators of the immune system. By restoring the T-lymphocyte mediated anti-tumor effect, immune checkpoint inhibitors (ICI) have revolutionized the treatment of solid tumors but have met rather modest success in hematological malignancies. Currently, the only FDA approved indications for ICI therapy are in classic hodgkin lymphoma and primary mediastinal B cell lymphoma. Multiple clinical trials have assessed ICI therapy alone and in combination with standard of care treatments in other lymphomas, plasma cell neoplasms and myeloid neoplasms but were noted to have limited efficacy. These trials mostly focused on PD-1/PDL-1 and CTLA-4 inhibitors. Recently, there has been an effort to target other T-lymphocyte checkpoints like LAG-3, TIM-3, TIGIT along with improving strategies of PD-1/PDL-1 and CTLA-4 inhibition. Drugs targeting the macrophage checkpoint, CD47, are also being tested. Long term safety and efficacy data from these ongoing studies are eagerly awaited. In this comprehensive review, we discuss the mechanism of immune checkpoint inhibitors, the key takeaways from the reported results of completed and ongoing studies of these therapies in the context of hematological malignancies.

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Agents that induce a shift in the activity state of the immune tumor microenvironment (TME) from “cold-to-hot” may increase response to immune checkpoint inhibitors. Here we examined whether TAK-243, a small molecule inhibitor of the ubiquitin activating enzyme (UAE), could heighten tumor immunogenicity and increase response to checkpoint inhibition. Our hypothesis was based on previous studies showing that TAK-243 induces ER stress (Hyer et al.) a phenomenon that can influence the status of the immune TME. While TAK-243 has previously shown anti-tumor potential, these studies were largely performed in immune-deficient models of cancer leaving potential influence on immune response in question. We first examined this potential using multiplexed trackable intratumor microdosing (CIVOTM, Presage Biosciences) to introduce TAK-243 alone or in combination with an anti-PD1 antibody (RPM1-14) to distinct localized positions within in a syngeneic model of lymphoma (A20). Response to localized drug exposure was then evaluated by immunohistochemistry and in situ hybridization biomarker analysis. TAK-243 induced elevation of multiple immune response biomarkers including 1) dendritic cell enrichment, 2) chemokine elevation, 3) TNFa elevation, and 4) CD8/Granzyme B elevation. We next examined whether TAK-243 could act as an “in situ vaccine” upon intratumor delivery and increase response to systemically delivered anti-PD1. Consistent with this potential, intratumor injection of TAK-243 resulted in greater regression of tumors in a dual flanked A20 xenograft model (ie one tumor on each flank of the host) when combined with systemically delivered anti-PD1 compared to either TAK-243 or anti-PD1 treatment alone. Importantly clear abscopal effects were induced as tumor regression was observed in both TAK-243 injected and non-injected tumors from subjects treated with the combination of TAK-243 and anti-PD1, 60% of which showed complete loss of tumor. Inhibition of the anti-tumor response was observed upon introduction of the drug combination with a CD8-depleting antibody. Furthermore, re-inoculation of subjects that exhibited complete regression of tumor masses with A20 cells showed no growth of new tumors. Taken together, these data suggest that intratumor injection of TAK-243 has potential to act as an in situ vaccine which increases anti-tumor immunogenicity and primes tumors for response to ICIs. Citation Format: Richard Klinghoffer, Connor Burns, Angela Merrell, Marc Grenley. TAK-243 increases tumor immunogenicity enhancing systemic anti-tumor immune response and tumor regression in combination with immune checkpoint inhibition in a syngeneic model of lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3476.

Treatment-refractory and relapsed disease remain leading causes of death for patients with lymphoma. Virtually all lymphomas are exquisitely sensitive to radiation, and α-particle radiation therapies are notably suited to targeting microcluster disease common in the setting of early relapse. Refractory or relapsed lymphoma may also involve the loss of therapeutic targets, but radiation may stimulate antitumor immune effects against disease with incomplete target expression. Such effects make immune checkpoint inhibition a compelling candidate for combination treatment. Methods: We evaluated the therapeutic efficacy of 211At-labeled antihuman CD20 monoclonal antibodies combined with immune checkpoint inhibition in human CD20 transgenic mice bearing murine lymphomas on opposing flanks that were either positive or negative for human CD20 expression (hCD20(+) and hCD20(-), respectively). Results: In the absence of 211At-hCD20, the antimurine checkpoint inhibitors PD1, CTLA4, CD47, and TIM3 had no efficacy given alone or in doublets. 211At-hCD20 given alone suppressed growth of both hCD20(+) and hCD20(-) tumors in a dose-dependent fashion, with predictably stronger suppression of hCD20(+) tumors. Strikingly, the addition of PD1 alone or the PD1 plus CTLA4 doublet to low-dose 211At-hCD20 significantly strengthened suppression of both tumors and increased mouse survival. Conclusion: Future translation of this synergistic combination of α-radiotherapy and immune checkpoint inhibition holds promise for the treatment of high-risk aggressive lymphomas, including cases with postinduction minimal residual disease or antigen loss after targeted therapies.

Intrathecal nivolumab combined with its systemic administration was recently found safe and effective in melanoma with leptomeningeal dissemination, prompting us to evaluate intraventricular nivolumab for recurrent primary CNS lymphoma (PCNSL) in an elderly patient unable to tolerate aggressive systemic polychemotherapy. Intraventricular nivolumab achieved a lasting (>12 months) complete remission including parenchymal lesions distant from cerebrospinal fluid spaces. No toxicities or adverse events related to the mode of administration were noted. Our case suggests intraventricular nivolumab is active in recurrent parenchymal PCNSL. Together with detected 9p24.1 gains this argues for further prospective evaluation, for which our treatment protocol provides a framework.

Background: Relapsed/refractory primary mediastinal large B-cell lymphoma (R/R PMBL) remains a therapeutic challenge, with limited responses to conventional salvage therapies. CAR-T cell therapy has emerged as a potential second-line (2L) option, but access may be restricted. Anti-PD1 checkpoint inhibitors (CPIs) have shown promising efficacy in clinical trials (KEYNOTE-170, CHECKMATE-436), but they lack European regulatory approval and real-world data in PMBL. We conducted a multicenter retrospective study to evaluate outcomes in R/R PMBL patients treated with CPIs. Methods: This study included R/R PMBL patients treated with CPIs, either alone or combined with other agents, across 20 LYSA-affiliated centers in France from 2014 to 2025. Tumor responses were assessed using PET or CT imaging, according to the 2014 Lugano criteria. The best overall response rate (bORR), defined as the proportion of patients achieving complete (CR) or partial (PR) response, was reported. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier (KM) method. Median follow-up was calculated using the reverse KM approach. Results: A total of 100 patients were included (median age 31 years, range 18–82; 51% female), with 98% presenting with a mediastinal mass, 58% with localized disease (stage I–II), 86% with ECOG PS 0–1, 10% with B symptoms, and 9% with a CNS-IPI score ≥4. Seven patients (7%) had central nervous system (CNS) involvement at inclusion. Most patients (95%) were refractory to their last line, with a median of 2 prior regimens (range 1–5), including R-CHOP14 (34%), R-CHOP21 (15%), DA-EPOCH-R (16%), R-ACVBP (25%), and others (10%) as first line. In 2L, 84% received platinum-based chemotherapy; prior autologous SCT and CAR-T were given in 3 and 7 patients, respectively. CPIs included pembrolizumab (n=66), nivolumab (n=33), and atezolizumab (n=1), administered as monotherapy (n=39), in combination with brentuximab vedotin (Bv; n=52), or with other agents (n=9). The median number of CPI cycles was 6 (IQR 3–15; range 1–52), and of Bv cycles was 4 (IQR 2–8; range 1–36). Consolidation therapy (57%) included radiotherapy (RT, n=20), autologous SCT (n=9), allogeneic SCT (n=3), and anti CD19 CAR-T cells (n=25). Treatment was generally well tolerated: 72% of patients experienced no adverse events, and most toxicities were low-grade, immune-related or infectious, consistent with previous reports. The bORR was 84%, including 48% CR and 36% PR. bORR by treatment subgroup was 89% with CPI monotherapy (CR 47%, PR 42%), 78% with CPI+Bv (CR 56%, PR 22%). The median time to best response was 2.9 months for monotherapy, 2.2 months for CPI+Bv. After a median follow-up of 31.8 months (IQR 11.9–51.8), median PFS and OS were not reached. Estimated 2-year PFS and OS rates were 56.6% [IC95: 46.9-68.2] and 75.5% [IC95: 66.5-85.7], respectively. A total of 27 deaths were reported; main cause of death was lymphoma (92.3%). Among the 48 patients who achieved CR, only 3 relapsed (median time to relapse: 12.3 months). Additionally, 54% of patients initially in PR converted to CR over time. In univariate Cox analysis, poor OS was associated with ECOG ≥2 (HR 3.88 [95% CI 1.53–9.84], advanced stage (HR 2.73 [1.25–5.97], CNS-IPI ≥4 (HR 6.66 [2.26–19.64], B symptoms (HR 4.18 [1.38–12.65] and LDH>ULN (HR 4.08 [1.21–13.76]. Hb ≥10.5 g/dL (HR 0.30 [0.14–0.67], platelet count ≥100 G/L (HR 0.20 [0.08–0.51], and female sex (HR 0.41, [0.18–0.94] were associated with better OS. In multivariate analysis, CNS-IPI was independently associated with shorter OS (HR 4.99 [2–3] and 4.48 [4–5]), while female sex (HR 0.19) and Hb ≥10.5 g/dL (HR 0.17) were linked to longer OS. Predictors of shorter PFS in univariate analysis included ECOG ≥2 (HR 3.98 [1.92–8.25]), advanced stage (HR 2.50 [1.30–4.80]), CNS-IPI ≥4 (HR 5.33 [2.19–12.98]), B symptoms (HR 4.41 [1.90–10.26]), and LDH>ULN (HR 3.11 [1.21–8.03]). Conversely, Hb ≥10.5 g/dL (HR 0.38 [0.20–0.75]) and platelets ≥100 G/L (HR 0.31 [0.13–0.70]) were associated with longer PFS. In multivariate analysis, only CNS-IPI remained independently associated with shorter PFS (HR 4.59 [2.09–10.08] for score 2–3; HR 4.78 [1.34–17.05]) for score ≥4. Conclusion: This large real-world cohort confirms the high efficacy and sustained responses of CPIs in R/R PMBL. These results support broader and earlier integration of CPIs in the treatment strategy for this high-risk population.

Introduction Diffuse large B-cell lymphoma (DLBCL) is clinically and biologically heterogenous. Though immune checkpoint inhibitors (ICI) have limited efficacy in unselected, heavily pre-treated DLBCL (Ansell JCO 2019), responses have been reported in select subgroups, e.g. primary mediastinal B-cell lymphoma and EBV-positive DLBCL (Armand Blood 2018, Nayak Blood 2017). In our phase II AvR-CHOP study, treatment-naïve DLBCL patients (pts) received priming with avelumab (anti-PD-L1) and rituximab (AvRp) prior to R-CHOP. Response to AvRp alone was observed in 57%, independent of established prognostic markers including International Prognostic Index, histologic subtype, cell-of-origin and baseline total metabolic tumour volume (TMTV). Novel biomarkers are thus needed to guide ICI use and further define the DLBCL immune landscape. PRAME, a cancer testis antigen expressed in ~30% of DLBCL, is highly immunogenic yet paradoxically linked to immune exclusion and checkpoint expression (Bose Int J Transl Med 2023). Its prognostic impact in chemotherapy-treated DLBCL is unclear, with both overexpression and deletions associated with poor outcomes (Mitsuhashi In J Haem 2014, Takata J Clin Invest 2022). Notably, autologous PRAME-specific T-cells have efficacy in non-Hodgkin and Hodgkin lymphoma, supporting its immunotherapeutic relevance (Vasileiou JCO 2021). We present the pre-specified translational analysis of the AvR-CHOP study. Methods Twenty-eight pts received AvRp x2, followed by R-CHOP x6 and avelumab consolidation. PET metrics (SUVmean, TMTV and total lesion glycolysis [TLG, SUVmean x TMTV]) were calculated with a fixed SUV >4 method (MIMEncore). Gene expression profiling (GEP) was performed using the NanoString PanCancer Immune Panel. Differential expression was analysed via Rosalind and custom pipelines, stratifying pts by >75% TLG reduction (TLG75) post AvRp. Whole exome sequencing (WES) used the Agilent SureSelect All Exon V8 platform. Molecular subtypes were assigned via LymphGen (Wright Cancer Cell 2020). Immune cell deconvolution, pathway enrichment, and gene set variation analysis (GSVA) were performed with CIBERSORTx and custom workflows. Associations with clinical outcomes were assessed by Kaplan-Meier analysis. Results GEP was available in 21 pts. Ten (48%) achieved TLG75, including 4 with complete metabolic response. Responses were seen across histologic subtypes. PRAME was amongst the most significantly differentially expressed genes and was upregulated in TLG75 responders (log2FC=3.84; p<0.001); 71% (10/14) of PRAME-high pts responded vs 0% (0/7) of PRAME-low. PRAME-high expression was associated with improved overall survival (OS; p=0.0314), while PRAME loss correlated with inferior progression-free survival (p<0.001) and OS (p=0.031). All 3 pts with PRAME deletions were refractory to both AvRp and R-CHOP. PRAME expression correlated with other cancer testis antigens CT45A1 (p=0.005) and MAGEA3 (p=0.013), but not PD-L1. PRAME-high tumours trended toward higher immune abundance scores, with enrichment of the immune regulation pathway (p=0.025). Pathway analysis showed upregulation of chemokine (p=0.038), cytokine (p=0.025), and tumour necrosis factor (TNF) signalling (p=0.031) in PRAME-high tumours. In TLG75 responders, GSVA revealed increased PD-1 signalling (p=0.017) and reduced IL-1 (p<0.001) and toll-like receptor signalling (p=0.047). LymphGen classification revealed subtype associations; all ST2 cases were PRAME-high and 5/6 achieved TLG75, whereas EZB and MCD subtypes were PRAME-lowwith no response. Tumours with high tumour mutational burden (TMB>10mut/Mb) were also enriched with PRAME-high expression (p=0.090). PRAME-specific T-cell responses, assessed via TCR sequencing and ELISpot, will be presented. ConclusionHigh PRAME expression identified a biologically distinct, ICI-sensitive DLBCL subgroup marked by co-expression of cancer testis antigens, upregulated immune signalling and enrichment for the ST2 molecular subtype. Despite expression of immune regulatory signatures, PRAME-high tumours respond to PD-L1 inhibition, suggesting a functionally suppressed but ICI-responsive microenvironment. These findings identify PRAME as a potential predictive biomarker in ICI-treated DLBCL and build on prior reports of PRAME-specific T-cell efficacy in lymphoma. Further study is warranted to elucidate the relationship between PRAME expression, tumour immunobiology and response to T cell–directed therapies in DLBCL.

Extranodal marginal zone lymphoma (EMZL) is the most common subtype of ocular lymphomas. Diffuse large B-cell lymphoma (DLBCL) and EMZL with large-cell transformation present diagnostic challenges. Radiotherapy is the standard treatment for ocular lymphomas, but complications and relapse are common. Diagnostic utility in challenging cases, as well as treatment options using immune checkpoint inhibitors, are unclear in ocular lymphomas. We herein investigated the PD-1, PD-L1, and IDO1 staining patterns in 20 cases of ocular lymphomas, including EMZL (n=14), EMZL with increased large cells (n=2), and DLBCL (n=4). PD-1, PD-L1, and IDO1 staining was not detected in lymphoma cells in any cases but was observed within the tumor microenvironment in all cases. Positivity for PD-1, PD-L1, and IDO1 in inflammatory cells was seen either intratumorally or peritumorally. In all 6 cases with significantly more large B cells, the density of PD-1, PD-L1, and IDO1 expression in the tumor microenvironment was higher than that of the remaining 14 cases without large B cells ( P -value<0.0001), whereas other clinicopathologic features showed no statistical correlation. Increased expression of PD-1, PD-L1, and IDO1 in the inflammatory milieu in cases with large cells may provide diagnostic utility in small biopsies as well as therapeutic potential.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL). Chemotherapy is one of the main treatments for cancer, but the antitumor effect of chemotherapeutic drugs is affected by the patient's immune status. The programmed cell death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) axis is an important central checkpoint in tumor progression. The present study demonstrated a significant synergistic effect of PD-1 inhibitor and oxaliplatin, cisplatin, etoposide, cytarabine, ifosfamide and carboplatin. There was no difference in cytotoxicity between the groups with or without PD-L1 inhibitor. It was also observed that cytotoxicity of T cells combined with PD-1 inhibitor against DLBCL cells was inhibited by dexamethasone addition to the culture system at 24, 48 and 72 h. There was no difference in cytotoxicity between the group of dexamethasone added at 96 h and the group without dexamethasone at 96 h. Then, we selected a PD-1 inhibitor combined with a chemotherapeutic regimen in a Pfeiffer cell mouse xenograft model. At 21 days, the reduction in tumor size was more obvious in the DHAP combined with PD-1 inhibitor group (dexamethasone after 96 h of PD-1) compared with that in the DHAP (

A novel therapeutic regimen showed that the oncolytic type II herpes simplex virus (oHSV2) was able to prevent colorectal cancer growth, recurrence, and metastasis. However, no study has yet explored whether oHSV2 has an impact on the development of diffuse large B-cell lymphoma (DLBCL). We chose the clinical chemotherapeutic drug doxorubicin (DOX) as a positive control to evaluate the effect of oHSV2 infection on the apoptotic, invasive, and proliferative capacity of DLBCL cells. We next further explored the therapeutic efficacy of oncolytic virus oHSV2 or DOX in DLBCL tumor bearing BALB/c mice, and evaluated the infiltration of CD8 + T cells and CD4 + T cells in tumor tissues. A pathological approach was used to explore the effects of oHSV2 on various organs of tumor bearing mice, including the heart, liver, and kidney. Next, SU-DHL-4 cells were co-cultured with cytotoxic T lymphocytes (CTLs) to mimic the tumor immune microenvironment (TME), to explore the impact of oHSV2 on the immune environment at the cellular level, and then analyzed the relationship between oHSV2 and the PD-1/PD-L1 immune-checkpoint. Subsequently, we further validated the efficacy of combined oHSV2 and PD-L1 treatment on transplanted tumor growth in mice at the

Double-expressor diffuse large B-cell lymphoma (DLBCL) with

The diffuse large B-cell lymphoma (DLBCL) has the highest incidence of all lymphomas worldwide. To investigate the functions of lymphocyte activation gene 3 (LAG-3) and programmed cell death 1 (PD-1) in tissues and peripheral blood of patients with DLBCL, the expression of LAG-3 and PD-1 genes in DLBCL-TCGA were analyzed. According to TCGA database, High LAG-3 and PD-1 levels significantly inhibit CD8

The diffuse large B-cell lymphoma (DLBCL) variant of Richter transformation (DLBCL-RT) is typically chemoresistant with poor prognosis. Aiming to explore a chemotherapy-free treatment combination that triggers anti-tumour immune responses, we conducted a phase 2 study of atezolizumab (a PD-L1 inhibitor) in combination with venetoclax and obinutuzumab in patients with DLBCL-RT. This was a prospective, open-label, multicentre, single-arm, investigator-initiated, phase 2 study in 15 hospitals in Italy and Switzerland. Eligible patients had a confirmed diagnosis of chronic lymphocytic leukaemia or small lymphocytic lymphoma as per the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) 2008 criteria with biopsy-proven transformation to DLBCL; had not previously received treatment for DLBCL-RT, although they could have received chronic lymphocytic leukaemia therapies; were aged 18 years or older; and had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2. No previous treatment with any of the drugs in the triplet combination was allowed. Patients received 35 cycles of 21 days of intravenous obinutuzumab (100 mg on day 1, 900 mg on day 2, 1000 mg on day 8 and day 15 of cycle 1; 1000 mg on day 1 of cycles 2-8) and intravenous atezolizumab (1200 mg on day 2 of cycle 1 and 1200 mg on day 1 of cycles 2-18), and continuous oral venetoclax (ramp-up from 20 mg/day on day 15 of cycle 1 according to chronic lymphocytic leukaemia schedule, then 400 mg/day from day 1 of cycle 3 to day 21 of cycle 35). The primary endpoint was overall response rate at day 21 of cycle 6 in the intention-to-treat population. We considered an overall response rate of 67% or more to be clinically active, rejecting the null hypothesis of a response of 40% or less. The study is registered with ClinicalTrials.gov, NCT04082897, and has been completed. Between Oct 9, 2019, and Oct 19, 2022, 28 patients were enrolled (12 [43%] male patients and 16 [57%] female patients). Median follow-up was 16·8 months (IQR 7·8-32·0). At cycle 6, 19 of 28 patients showed a response, yielding an overall response rate of 67·9% (95% CI 47·6-84·1). Treatment-emergent adverse events that were grade 3 or worse were reported in 17 (61%; 95% CI 40·6-78·5) of 28 patients, with neutropenia being the most frequent (11 [39%; 21·5-59·4] of 28 patients). Serious treatment-emergent adverse events were reported in eight (29%; 14·2-48·7) patients, which were most commonly infections (five [18%; 6·1-36·9] of 28 patients). There were two (7%) deaths attributable to adverse events during the study: one from sepsis and one from fungal pneumonia, which were not considered as directly treatment-related by the investigators. Six (21·4%) patients had immune-related adverse events, none of which led to discontinuation. No tumour lysis syndrome was observed. The atezolizumab, venetoclax, and obinutuzumab triplet combination was shown to be active and safe, suggesting that this chemotherapy-free regimen could become a new first-line treatment approach in patients with DLBCL-RT. Roche.

MicroRNAs (miRs) are involved in lymphoma progression by regulating tumor cell interaction with microenvironment. MiR155 is overexpressed in diffuse large B-cell lymphoma (DLBCL) and its biological effect on tumor microenvironment needs to be futher investigated. MiR155 was detected by quantitative real-time PCR in patients with newly diagnosed DLBCL. The mechanism of action of miR155 on lymphoma progression and tumor microenvironment was examined in vitro in B-lymphoma cell lines and in vivo in a murine xenograft model. Serum miR155 was significantly elevated, correlated with tumor miR155 expression, and indicated poor disease outcome in DLBCL. MiR155 overexpression was associated with decreased peripheral blood CD8+T cells and inhibition of T-cell receptor signaling. Of note, EBV-positive patients showed higher serum miR155 than EBV-negative patients. In co-culture systems of B-lymphoma cells with immune cells, miR155 induced Fas-mediated apoptosis of CD8+T cells, which could be targeted by anti-PD-1 and anti-PD-L1 antibodies. Moreover, miR155 enhanced lymphoma cell PD-L1 expression, recruited CD8+T cells by PD-1/PD-L1 interaction and inhibited CD8+T cell function via dephosphorylating AKT and ERK. MiR155-induced AKT/ERK inactivation was more obvious in CD8+T cells co-cultured with EBV-infected B-lymphoma cells. In vivo in a murine xenograft model established with subcutaneous injection of A20 cells, PD-L1 blockade particularly retarded miR155-overexpressing tumor growth, consistent with maintenance of CD8+T cells and their function. As a oncogenic biomarker of B-cell lymphoma, serum miR155 was related to lymphoma progression through modulating PD-1/PD-L1-mediated interaction with CD8+T cells of tumor microenvironment, indicating the sensitivity of B-cell lymphoma to PD-L1 blockade. Also CD8+T cells could be a therapeutic mediator of immune checkpoint inhibitors in treating EBV-associated lymphoid malignancies.

Primary mediastinal large B-cell lymphoma (PMBCL) is a rare aggressive B-cell lymphoma characterized by the frequent presence of amplification and translocation events at 9p24.1, resulting in the expression of the programmed cell death-1 (PD-1) ligands PD-L1 and PD-L2. Pembrolizumab, a humanized anti-PD-1 monoclonal antibody, binds PD-1 and blocks this interaction, enhancing the activity of the immune system against tumor cells, and has shown activity in PMBCL and in some cases of primary and secondary central nervous system (CNS) lymphoma. We report the case of a 40-year-old woman diagnosed with relapsed PMBCL and secondary CNS involvement who responded to pembrolizumab monotherapy, allowing for a later allogeneic stem cell transplant.

CD19-directed chimeric antigen receptor-modified (CAR T) T cells achieve durable remissions in about 30% to 40% of relapsed/refractory large B-cell lymphomas. T-cell exhaustion and/or an immunosuppressive tumor microenvironment may contribute to CAR T-cell failure. Pembrolizumab, an anti-PD1 immune checkpoint inhibitor, may reverse T-cell exhaustion after CAR T-cell therapy. We treated 12 patients with B-cell lymphomas who were either refractory to (n = 9) or relapsed after (n = 3) CD19-directed CAR T-cell (4-1BB-costimulated) therapy with pembrolizumab 200 mg IV every 3 weeks. Median time from CAR T-cell infusion to first pembrolizumab dose was 3.3 months (range, 0.4-42.8 months). Pembrolizumab was well tolerated, and the only grade ≥3 adverse events related to pembrolizumab were neutropenia (n = 3; 25%). Best overall response rate after pembrolizumab was 25% (3 of 12 patients; 1 complete response; 2 partial responses). One (8%) patient had stable disease; thus, 4 of 12 (33%) patients had clinical benefit. After pembrolizumab, 4 patients with clinical benefit had an increase in percentage of CAR T cells by mass cytometry by time of flight (CyTOF); 3 of 4 of these patients also had increases in CAR19 transgene levels by quantitative polymerase chain reaction. Deep immune profiling using CyTOF revealed increased CAR T-cell activation and proliferation and less T-cell exhaustion in clinical responders. Together, PD1 blockade with pembrolizumab after CD19-directed CAR T-cell therapy appears safe and may achieve clinical responses in some patients with B-cell lymphomas refractory to or relapsed after CAR T-cell therapy. This trial was registered at www.clinicaltrials.gove as #NCT02650999.

Outcomes after programmed death-1 (PD-1) blockade in B-cell lymphomas are disappointing with few durable responses. Histone deacetylase inhibitors exhibit favorable immunomodulatory effects and demonstrate synergistic anti-tumor immune responses with anti-PD-1 therapy in preclinical models. We, therefore, developed a phase I study to evaluate the safety and preliminary efficacy of pembrolizumab with vorinostat in relapsed/refractory B-cell lymphomas. Patients were treated in a dose-escalation cohort using a Rolling 6 design followed by an expansion cohort at the recommended phase II dose (R2PD). Fifty-two patients were enrolled (32 Hodgkin and 20 non-Hodgkin lymphoma [NHL]). Here, we report safety data from the dose escalation cohort, and the toxicity and efficacy within NHL patients. Vorinostat was administered twice daily on days 1-5 and 8-12 (dose-level [DL]1: 100 mg; DL2: 200 mg) and pembrolizumab (200 mg) was administered on day 1 of each 3-week cycle. Of six patients treated at DL1, one had a dose-limiting toxicity (DLT) (Stevens-Johnson syndrome [SJS]), and one of six had a DLT at DL2 (thromboembolism); therefore, DL2 was the RP2D. The patient developing SJS was treated with corticosteroids, infliximab, and cyclosporine but ultimately died of invasive fungal infection from the extensive immunosuppression used to treat the SJS. The most common adverse events were hypertension, diarrhea, and cytopenias. Of 20 NHL patients, nine had follicular lymphoma (FL) and 11 had diffuse large B-cell lymphoma (DLBCL). Five DLBCL patients had primary mediastinal B-cell lymphoma (PMBL). The complete and overall response rates (CR and ORR) were 11% and 22% for FL and 45% and 55% for all DLBCL. Amongst DLBCL, the CR and ORR was 80% and 80% for PMBL and 17% and 33% for non-PMBL. In conclusion, pembrolizumab with vorinostat was tolerable and produced responses in relapsed/refractory B-cell NHL, with particularly notable efficacy in PMBL (clinicaltrials gov. Identifier: NCT03150329).

No abstract

Autologous stem cell transplantation (ASCT) is a standard of care for patients with chemosensitive, relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and diffuse large B cell lymphoma (DLBCL). Whereas the clinical benefit of ASCT has traditionally been attributed solely to cytoreduction from intensive chemotherapy, ASCT has important immunogenic effects that may contribute to its antitumor efficacy and could provide a favorable immune environment for post-ASCT immune-based maintenance treatments. We previously reported clinical results of a phase II trial (ClinicalTrials.gov identifier NCT02362997) testing 8 doses of pembrolizumab maintenance therapy after ASCT for patients with R/R cHL or DLBCL. To clarify the impact of pembrolizumab on immune reconstitution, we compared the kinetics of peripheral blood immune cell recovery after ASCT for trial patients receiving pembrolizumab maintenance to those of a contemporaneous control cohort of similar patients undergoing ASCT without pembrolizumab maintenance. This study was conducted to characterize the impact of post-ASCT pembrolizumab maintenance therapy on immune reconstitution for patients with R/R DLBCL and cHL and to identify candidate biomarkers of efficacy and immune-related adverse events (irAEs). Peripheral blood (PB) mononuclear cell samples were prospectively collected at 1 to 18 months after ASCT and analyzed by flow cytometry using a panel of fluorophore-conjugated monoclonal antibodies to identify B cells, natural killer (NK) cells, and various dendritic cell (DC) and T cell subsets. A median of 5 (range, 1 to 8) post-ASCT PB samples were collected from 144 patients (59 in the pembrolizumab group and 85 in the control group). Clinical characteristics of the 2 cohorts were similar. Compared with cHL patients, DLBCL patients (all of whom received anti-CD20 monoclonal antibody therapy before ASCT) had delayed CD19

Despite improvement in survival in diffuse large B-cell lymphoma (DLBCL) with the introduction of rituximab, central nervous system (CNS) relapse continues to represent a clinical challenge. In diffuse large B-cell lymphoma (DLBCL), the incidence of CNS relapse is only ∼5% in unselected cohorts. Immunotherapy is the treatment that either boosts the patient's own immune system or uses man-made versions of the normal parts of the immune system to kill lymphoma cells or slow their growth. We are presenting a thirty-eight year old man who, presented with neck nodes, axillary nodes, altered sensorium, abnormal body movements, unconsciousness, weight loss and, fever, with a past history of DLBCL in May 2008, treated with 6 cycles of CHOP and completed in November 2008. After 9 years in April 2018, the patient developed similar symptoms and treated with salvage chemotherapy with R-DHAP which was completed in September 2018. Post-treatment PET-CT showed partial metabolic response and we started external beam radiotherapy to initial bulky disease. After completion of radiotherapy, the patient was very reluctant for any type of therapy and went home. After one month he presented to us with persistent vomiting, abnormal body movements and, altered sensorium. On examination, his Glasgow Coma Scale (GCS) was E2V3M2 and he was admitted in Intensive Care Unit. The patient was managed with mannitol, dexamethasone, antiepileptics, antibiotics and other supportive care medicines. His brain magnetic resonance imaging (MRI) was showing multiple heterogeneously enhancing lesions with surrounding vasogenic oedema and his cerebrospinal fluid analysis was positive for malignant cells. He was managed with triple intrathecal chemotherapy with methotrexate 12 mg, Cytarabine 50 mg, and Hydrocortisone 50 mg along with other supportive care medicines, and after 4-5 days he regained consciousness and he was able to talk and understand verbal commands. In view of improvement in general condition and performance status, we started biweekly triple intra-thecal therapy, and Inj. Nivolumab 3 mg per kg q 2 weekly. From the second cycle, we started Lenalidomide 10 mg once a day for 21 days with 7 days gap along with 2 weekly nivolumab and biweekly triple IT chemotherapy. After one month his CSF analysis was negative for malignant cells. Now he is on regular treatment with weekly IT chemotherapy, 2 weekly nivolumab and 3 weeks on and one week off lenalidomide. After 2 months of treatment, his MRI Brain was showing. At the time of submission of this article, he has completed the fifth cycle of immunotherapy and two cycles of lenalidomide. He was able to manage his daily ADL and able to walk with a stick. The patient tolerated immunotherapy, triple IT therapy and lenalidomide very well without much intolerable side effects. Therefore, we concluded that nivolumab and lenalidomide was well tolerated and exhibited antitumor activity in extensively pretreated patients with relapsed or refractory sanctuary site CNS B- cell lymphomas. Additional studies of Nivolumab and lenalidomide in these diseases are ongoing.

Immunotherapy is the treatment that either boosts the patient's immune system or uses human-made versions of the normal parts of the immune system to kill lymphoma cells or slow their growth. A forty-eight-year-old lady with neck nodes, axillary nodes, weight loss and fever diagnosed to have Diffuse Large B-Cell Lymphoma (DLBCL) in December 2009 was treated with 6 cycles of R-CHOP, and her treatment was completed in May 2010. After 2 years in July 2012, the patient developed similar symptoms and received salvage chemotherapy with R-DHAP, and her treatment was completed in January 2013. After one and a half years, in August 2014, the patient again had relapsed DLBCL. She was treated with R-ICE 4-cycles and rendered disease-free following allogeneic HSCT in June 2015. But in December 2016, the patient again developed isolated axillary lymphadenopathy and relapsed DLBCL was confirmed by HPR and IHC. This time, the patient was unwilling to go on chemotherapy, but after counselling about the new drug, Nivolumab, she became convinced, and her treatment was started with 3mg per kg every 2 weeks. After 4 cycles, she had a complete response and is now being treated with the same treatment without any symptoms of the disease or any adverse drug reactions. Nivolumab was well tolerated and exhibited antitumor activity in extensively pretreated patients with relapsed or refractory B- cell lymphomas. Additional studies are ongoing to learn more about the use of Nivolumab in these diseases.

TTI-621 (SIRPα-IgG1 Fc) is a novel checkpoint inhibitor that activates antitumor activity by blocking the CD47 "don't eat me" signal. This first-in-human phase I study (NCT02663518) evaluated the safety and activity of TTI-621 in relapsed/refractory (R/R) hematologic malignancies. Patients with R/R lymphoma received escalating weekly intravenous TTI-621 to determine the maximum tolerated dose (MTD). During expansion, patients with various malignancies received weekly single-agent TTI-621 at the MTD; TTI-621 was combined with rituximab in patients with B-cell non-Hodgkin lymphoma (B-NHL) or with nivolumab in patients with Hodgkin lymphoma. The primary endpoint was the incidence/severity of adverse events (AEs). Secondary endpoint included overall response rate (ORR). Overall, 164 patients received TTI-621: 18 in escalation and 146 in expansion (rituximab combination, TTI-621 was well-tolerated and demonstrated activity as monotherapy in patients with R/R B-NHL and T-NHL and combined with rituximab in patients with R/R B-NHL.

Refractory/relapsed B cell lymphoma patients who received the available anti-CD19 chimeric antigen receptor (CAR) T cells may still experience a short duration of remission. Here in this study, we evaluated the safety and efficacy of a novel dominant-negative programmed cell death-1 (PD-1) armored anti-CD19 CAR T cells. A total of 9 patients (including 4 diffuse large B cell lymphomas, DLBCL, 2 transformed follicular lymphomas, TFL, and 3 follicular lymphomas, FL) received the novel CAR T cells infusion at a dose of more than 1 × 10

CD19-directed chimeric antigen receptor T cell (CART19) therapy is efficient and approved for relapsed/refractory diffuse large B cell lymphoma (DLBCL). To increase durable antitumor response, we previously designed tandem CART19/20 cells and shown longer progression-free survival. However, a proportion of CART19/20-treated patients will finally progress and require salvage therapies. In this study, we analyzed data from five patients with relapsed/refractory DLBCL who had disease progression or relapse following CART19/20 therapy and then treated with PD-1-blocking antibodies as salvage therapy. Two of five patients acquired complete remissions after anti-PD-1 therapy, including one patient remained ongoing remission for more than 21 months. One patient achieved a partial remission, and the other two had progressive diseases. No ≥ grade 3 treatment-related adverse events or cytokine release syndrome was observed. Immunohistochemistry of tumor specimens revealed higher PD-1/PD-L1 expression in responsive patients with anti-PD-1 therapy as compared to that in non-responders. After anti-PD-1 treatment, circulating T cells were activated in responders, and no significant expansion of CART19/20 cells was detected. Our data suggest that PD-1 blockade therapy can be active in patients with relapsed/refractory DLBCL after failure of CAR T cell therapy who had PD-L1 expression in tumor cells and high PD-1 level in tumor-infiltrated T cells.

Targeted immunotherapy based on PD-1/PD-L1 suppression has revolutionized the treatment of various solid tumors. A remarkable improvement has also been observed in the treatment of patients with refractory/relapsing classical Hodgkin lymphoma (cHL). We investigated PD-L1 status in a variety of treatment resistant lymphomas. Tumor samples from 78 patients with therapy resistant lymphomas were immunohistochemically (IHC) investigated for the expression of PD-L1 using two antibody clones (SP142 and SP263, Ventana). Thirteen PD-L1+ cases were further analyzed for gene copy number variations (CNV) by NGS and for PD-L1/JAK2/PD-L2 co-amplification using fluorescent in-situ hybridization assay (FISH). PD-L1 positivity (≥5% positive cancer cells, IHC) was present in 32/77 (42%) and 33/71 cases (46%) using SP142 and SP263 antibodies, respectively. Concordance between the two anti-PD-L1 clones was high with only three (4%) discrepant cases. The strongest and consistent (10/11 cases) expression was observed in cHL and primary mediastinal B-cell lymphomas (3/3). Diffuse large B-cell lymphomas (DLBCL) were frequently positive (13/26) irrespective of subtype. Follicular (1/8), peripheral T-cell (3/11) and mantle cell (1/8) lymphomas were rarely positive, while small lymphocytic lymphoma/CLL and marginal zone lymphomas were consistently negative (3/3). Co-amplification/CNVs of PD-L1/JAK2/PD-L2 were observed in 3 cases of DLBCL and cHL, respectively. Of note, all three cHL-amplified cases were positive by FISH, but not by NGS. Since only a fraction of the IHC positive lymphoma cases were positive by FISH and NGS assays, other mechanisms are involved in PD-L1 upregulation, especially in DLBCL. FISH assay may be more suitable than NGS assay for determination of PD-L1 alterations in cHL.

CD19-targeted chimeric antigen receptor T (CAR T) cell therapy is a promising option to treat relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL). However, the majority of CAR T-treated patients will eventually progress and require salvage treatment, for which there is no current standard. In this study, we analyzed data from 6 patients with R/R DLBCL who experienced progression following CD19-CAR T therapy, and then received CD19-specific CAR T cells that express a PD-1/CD28 chimeric switch-receptor (CD19-PD-1/CD28-CAR T) as salvage therapy at our institution. After the second infusion of CAR T cells, 3 of 6 patients achieved complete remissions and the duration of the response of responsive patients ranged from 8 to 25 months. One patient showed a stable disease. In contrast, 2/6 patients died on 60 days because of progression disease. Importantly, no severe neurologic toxicity or cytokine release syndrome was observed. These data suggest that CD19-PD-1/CD28-CAR-T cells, a novel anti-CD19 CAR-T cell therapy, elicit a potent and durable anticancer response, and can be used in the post-CD19-CAR T failure setting.

HIV-associated lymphoma (HAL) is an aggressive malignancy directly linked to HIV infection and accounts for more than 30% of cancer-related deaths in people living with HIV (PLWH). HAL subtypes, including diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma (BL), primary effusion lymphoma (PEL), and plasmablastic lymphoma (PBL), exhibit five to ten times higher incidence rates and distinct molecular profiles compared to HIV-negative lympho-mas. Pathogenesis involves HIV-driven CD4+ T-cell depletion, chronic B-cell activation, and on-cogenic viral coinfection. First-line therapy combines antiretroviral therapy (ART) with chemo-therapy, achieving complete remission rates of 60-70% for DLBCL using R-EPOCH and 50-60% for BL with CODOX-M/IVAC. Relapsed/refractory cases show durable responses to CD19-CAR-T therapy; however, only 10% of HAL patients are enrolled in pivotal immunotherapy tri-als. Severe immunosuppression necessitates PET-CT-guided de-escalation and nanoparticle-based drug delivery systems to minimize toxicity. Emerging strategies include PD-1 inhibitors and broad-spectrum antivirals targeting HIV reservoirs, underscoring the need for precision med-icine that integrates tumor genomics and viral dynamics.

No abstract

Chimeric antigen receptor T cell (CART) therapy has benefited many refractory lymphoma patients, but some patients experience poor effects. Previous studies have shown that programmed cell death protein-1 (PD-1) inhibitors can improve and prolong the therapeutic effect of CAR-T cell treatment. A 61-year-old male presented with 15-d history of diarrhea and lower-limb edema. A large mass was detected in the pelvis, and pathology indicated non-Hodgkin diffuse large B-cell lymphoma. After three cycles of the R-CHOP chemotherapeutic regimen, the patient showed three subcutaneous nodules under the left armpit and both sides of the cervical spine. Pathological examination of the nodules indicated DLBCL again. The patient was diagnosed with relapsed and refractory diffuse large B-cell lymphoma. We recommended CAR-T cell treatment. Before treatment, the patient's T cell function and expression of immune detection points were tested. Expression of PD-1 was obviously increased (52.7%) on cluster of differentiation (CD)3+ T cells. The PD-1 inhibitor (3 mg/kg) was infused prior to lymphodepleting chemotherapy with fludarabine and cyclophosphamide. CAR-CD19 T cells of 3 × 10 This case suggests that the combination of PD-1 inhibitors and CAR-T cells improved therapeutic efficacy in B-cell lymphoma.

Mediastinal involvement is considered essential for the diagnosis of primary mediastinal large B-cell lymphoma (PMBL). However, we have observed cases of diffuse large B-cell lymphoma (DLBCL) with features of PMBL but without detectable mediastinal involvement. The goal was to assess our previously established gene expression profiling (GEP) signature for PMBL in classifying these cases. In a large series of DLBCL cases, we identified 24 cases with a GEP signature of PMBL, including 9 cases with a submission diagnosis of DLBCL consistent with PMBL (G-PMBL-P) and 15 cases with a submission diagnosis of DLBCL. The pathology reviewers agreed with the diagnosis in the 9 G-PMBL-P cases. Among the other 15 DLBCL cases, 11 were considered to be PMBL or DLBCL consistent with PMBL, 3 were considered to be DLBCL, and 1 case was a gray-zone lymphoma with features intermediate between DLBCL and classical Hodgkin lymphoma. All 9 G-PMBL-P and 9 of the 15 DLBCL cases (G-PMBL-M) had demonstrated mediastinal involvement at presentation. Interestingly, 6 of the 15 DLBCL cases (G-PMBL-NM) had no clinical or radiologic evidence of mediastinal involvement. The 3 subgroups of PMBL had otherwise similar clinical characteristics, and there were no significant differences in overall survival. Genetic alterations of CIITA and PDL1/2 were detected in 26% and 40% of cases, respectively, including 1 G-PMBL-NM case with gain of PDL1/2. In conclusion, PMBL can present as a nonmediastinal tumor without evidence of mediastinal involvement, and GEP offers a more precise diagnosis of PMBL.

Composite lymphoma is a well-known diagnostic entity exhibiting the synchronous occurrence of two or more distinct types of lymphomas in the same specimen. Here we report two patients, a 14-year-old female (Case 1) and a 45-year-old male (Case 2), with mediastinal composite lymphoma, comprising nodular sclerosis classic Hodgkin lymphoma (NSCHL) and primary mediastinal large B-cell lymphoma (PMBL). Both patients had a mediastinal mass, and manifested two different histologic components in the same biopsy, one characteristic of NSCHL and the other PMBL. The NSCHL areas included Hodgkin and Reed-Sternberg (HRS) cells with typical immunophenotypic features (CD30-positive and CD20-negative), whereas the sheets of large tumor cells characteristic of PMBL were strongly and uniformly CD20-positive. Interestingly, although both cases showed neoplastic PD-L1 (nPD-L1) positivity on the HRS cells of NSCHL, they differed regarding nPD-L1 expression on the PMBL tumor cells. In Case 1, the nPD-L1-negative PMBL component was anatomically situated outside the NSCHL lesion. On the other hand, in Case 2, the nPD-L1-positive PMBL component was characterized by transitional or continuous areas with the NSCHL component. These findings suggested that nPD-L1 expression may define two subtypes of PMBL that are more similar to or distinct from classic Hodgkin lymphoma.

Primary mediastinal large B-cell lymphoma (PMBL) is a distinct subtype of diffuse large B-cell lymphoma (DLBCL) that shows overlap with classical Hodgkin lymphoma (CHL) and a favorable prognosis compared to mediastinal gray-zone lymphoma (MGZL). We performed immunohistochemistry on initial diagnostic specimens of 49 cases of uniformly treated PMBL to determine the frequency and clinical significance of expression of antigens commonly seen in CHL and MGZL, along with markers previously shown to be prognostic in DLBCL, not otherwise specified. The median age was 37 years with a female:male ratio of 2.3. After a median follow-up of 78 months, 24% of patients had relapsed or refractory disease and 22% had died; the 5-year PFS was 70%. Variable CD15 expression was seen in 31% of cases, but was not associated with adverse outcome. Hans cell-of-origin, proliferation index, and MYC/BCL2 coexpression were not associated with outcome, while low PDL1 (P = 0.011) and high MUM1 (P = 0.065) staining were each associated with shorter PFS. A biologic risk score (one point each for low PDL1 and high MUM1) stratified patients into three prognostic risk groups for PFS (P = 0.001) and OS (P = 0.032). On separate multivariate models, low PDL1 was independent of R-IPI risk group for PFS (HR 6.0, P = 0.023), as was a biologic risk score of 2 (HR 5.6, P = 0.011). Incorporation of the biologic risk score sub-stratified patients within R-IPI groups for both PFS (P < 0.001) and OS (P < 0.001). In summary, we characterize the immunophenotypic spectrum of PMBL and identify PDL1 and MUM1 as prognostic biomarkers for high-risk disease. Am. J. Hematol. 91:E436-E441, 2016. © 2016 Wiley Periodicals, Inc.

PD-1 checkpoint blockade therapy (CBT) has greatly benefited patients with select solid tumors and lymphomas but has limited efficacy against diffuse large B-cell lymphoma (DLBCL). Because numerous inhibitory checkpoint receptors have been implicated in driving tumor-specific T cell dysfunction, we hypothesized that combinatorial CBT would enhance the activity of anti-PD-1-based therapy in DLBCL. T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is a coinhibitory receptor expressed on dysfunctional tumor-infiltrating T cells, and TIGIT blockade has demonstrated encouraging activity in combination with PD-1 blockade in murine tumor models and in clinical studies. However, the degree to which TIGIT mediates T cell dysfunction in DLBCL has not been fully explored. Here, we demonstrate that TIGIT is broadly expressed on lymphoma-infiltrating T cells (LITs) across a variety of human lymphomas and is frequently coexpressed with PD-1. TIGIT expression is particularly common on LITs in DLBCL, where TIGIT These results provide rationale for clinical investigation of TIGIT and PD-1 blockade in lymphomas, including DLBCL.

Richter syndrome (RS) represents the occurrence of an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL), in patients with chronic lymphocytic leukemia (CLL). Most cases of RS originate from the direct transformation of CLL, whereas 20% are de novo DLBCL arising as secondary malignancies. Multiple molecular mechanisms contribute to RS pathogenesis. B-cell receptor (BCR) overreactivity to multiple autoantigens is due to frequent stereotyped BCR configuration. Genetic lesions of TP53, CDKN2A, NOTCH1 and c-MYC deregulate DNA damage response, tumor suppression, apoptosis, cell cycle and proliferation. Hyperactivation of Akt and NOTCH1 signaling also plays a role. Altered expression of PD-1/PD-L1 and of other immune checkpoints leads to RS resistance to cytotoxicity exerted by T-cells. The molecular features of RS provide vulnerabilities for therapy. Targeting BCR signaling with noncovalent BTK inhibitors shows encouraging results, as does the combination of BCL2 inhibitors with chemoimmunotherapy. The association of immune checkpoint inhibitors with BCL2 inhibitors and anti-CD20 monoclonal antibodies is explored in early phase clinical trials with promising results. The development of patient-derived xenograft mice models reveals new molecular targets for RS, exemplified by ROR1. Although RS still represents an unmet medical need, understanding its biology is opening new avenues for precision medicine therapy.

Richter Syndrome (RS) is defined as the development of an aggressive lymphoma in the context of Chronic Lymphocytic Leukemia (CLL), with a Diffuse Large B-Cell Lymphoma (DLBCL) histology in 95% cases. RS genomic landscape shares only a few features with We reviewed available PubMed literature about RS genomics, PD-1/PD-L1 (Programmed Death 1/Programmed Death Ligand 1) pathway triggering and subsequent new therapeutic options. Data from about 207 patients from four landmark papers were compiled to build an overview of RS genomic lesions and point mutations. A number of these abnormalities may be involved in tumor microenvironment reshaping. T lymphocyte exhaustion through PD-L1 overexpression by tumor cells and subsequent PD-1/PD-L1 pathway triggering is frequently reported in solid cancers. This immune checkpoint inhibitor is also described in B lymphoid malignancies, particularly CLL: PD-1 expression is reported in a subset of prolymphocytes from the CLL lymph node proliferation centers. However, there is only few data about PD-1/PD-L1 pathway in RS. In RS, PD-1 expression is a hallmark of recently described « Regulatory B-cells », which interact with tumor microenvironment by producing inhibiting cytokines such as TGF-β and IL-10, impairing T lymphocytes anti-tumoral function. Based upon the discovery of high PD-1 expression on tumoral B lymphocyte from RS, immune checkpoint blockade therapies such as anti-PD-1 antibodies have been tested on small RS cohorts and provided heterogeneous but encouraging results. RS genetic landscape and immune evasion mechanisms are being progressively unraveled. New protocols using targeted treatments such as checkpoint inhibitors as single agents or in combination with immunochemotherapy are currently being evaluated.

Preclinical data demonstrated that combining an anti-programmed cell death 1 (PD-1) inhibitor with a cyclin-dependent kinase 9 (CDK9) inhibitor provided enhanced antitumor activity with no significant toxicities, suggesting this combination may be a potential therapeutic option. The multicohort, phase 1 KEYNOTE-155 study evaluated the safety and antitumor activity of the PD-1 inhibitor pembrolizumab plus the CDK9 inhibitor dinaciclib in patients with relapsed or refractory (rr) chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL) and multiple myeloma (MM). Patients enrolled were ≥18 years of age with a confirmed diagnosis of CLL, DLBCL, or MM. The study included 2 phases: a dose-evaluation phase to determine dose-limiting toxicities and a signal-detection phase. Patients received pembrolizumab 200 mg every 3 weeks plus dinaciclib 7 mg/m2 on day 1 and 10 mg/m2 on day 8 of cycle 1 and 14 mg/m2 on days 1 and 8 of cycles 2 and later. Primary endpoint was safety, and a key secondary endpoint was objective response rate (ORR). Seventy-two patients were enrolled and received ≥1 dose of study treatment (CLL, n = 17; DLBCL, n = 38; MM, n = 17). Pembrolizumab plus dinaciclib was generally well tolerated and produced no unexpected toxicities. The ORRs were 29.4% (5/17, rrCLL), 21.1% (8/38, rrDLBCL), and 0% (0/17, rrMM), respectively. At data cutoff, all 72 patients had discontinued treatment, 38 (52.8%) because of progressive disease. These findings demonstrate activity with combination pembrolizumab plus dinaciclib and suggest that a careful and comprehensive approach to explore anti-PD-1 and CDK9 inhibitor combinations is warranted. This trial was registered at www.clinicaltrials.gov as NCT02684617.

The risk of relapse among high-risk patients with diffuse large B-cell lymphoma (DLBCL) in complete metabolic remission (CMR) after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) therapy is 20% to 25%. Here, we evaluated whether consolidation with the programmed cell death ligand 1 checkpoint inhibitor atezolizumab could reduce the relapse risk. In this phase 2, open-label trial, patients with DLBCL with an International Prognostic Index (IPI) score of ≥3 and CMR after R-CHOP received 1200 mg atezolizumab every 3 weeks for 18 cycles. The primary end point was disease-free survival (DFS) at 2 years, with the aim of improving it to 89% compared to historical 79%. Secondary end points included overall survival (OS) and safety (Common Terminology Criteria for Adverse Events version 4.0). Analyses were on an intention-to-treat principle. Of 109 patients, 65% completed treatment. The cohort was 59% males, with 63% having high-intermediate risk IPI scores. At a median follow-up of 36.4 months, 15 relapses occurred (median, 8.2 months). The 2-year DFS was 87.9% (90% confidence interval [CI], 81.5-92.1), and the 2-year OS was 96.3% (90% CI, 91.7-98.3), meeting the primary objective. Treatment with salvage chemotherapy resulted in 10 of 13 patients achieving a second CMR. OS was significantly better among atezolizumab-treated patients than in a population-based matched control cohort from the Netherlands Cancer Registry. Adverse events (AEs) affected 79% of patients, with 18% developing immune-related AEs, including 4.5% grade 3 to 4. Atezolizumab consolidation significantly improved DFS in high-risk patients with DLBCL compared to historical cohorts. OS was significantly better than a population-based control cohort. These findings warrant further validation and assessment of immune checkpoint inhibitors as consolidation strategy in DLBCL. This trial was registered at www.clinicaltrials.gov as #NCT03463057.

Primary mediastinal B-cell lymphoma (PMBCL) is a rare but aggressive mature B-cell lymphoma that arises from thymic B cells and most commonly affects adolescents and young adults. PMBCL is now recognized by the WHO as a distinct entity from diffuse large B-cell lymphoma (DLBCL), not otherwise specified, with a unique clinical presentation and distinct morphologic features and molecular alterations. Similar to classic Hodgkin lymphoma, PMBCL tumors are characterized by alterations in the nuclear factor-κB and JAK/STAT pathways. These tumors also exhibit an immune evasion phenotype marked by upregulation of PD-L1 and loss of B2M. Historic data indicates that outcomes for pediatric patients with PMBCL are inferior compared with pediatric patients with DLBCL treated on the same protocols, and there is no current standard approach to initial treatment. Common regimens used for children with PMBCL include multiagent chemotherapy regimens designed for Burkitt lymphoma, such as Lymphomes Malins B (LMB)-based or Berlin-Frankfurt-Münster (BFM)-based chemotherapy ± rituximab. Based on initial data in adults showing excellent outcomes with the use of DA-EPOCH-R regimens, these regimens have also been adopted in pediatrics, although with mixed results. Novel agents are currently being studied in PMBCL with the goal of improving outcomes and reducing reliance on radiation and/or high-dose chemotherapy. Immune checkpoint blockade with PD-1 inhibition is of particular interest given the upregulation of PD-L1 in PMBCL and the known efficacy of these agents in the relapsed setting. Future efforts in PMBCL will also seek to determine the role of FDG-PET in evaluating response to therapy and the role of biomarkers in risk stratification.

Primary mediastinal B-cell lymphoma (PMBCL) is recognized as a distinct clinicopathologic entity that predominantly affects adolescents and young adults (AYA) and is more common in females. Although PMBCL was previously considered to be a subtype of diffuse large B-cell lymphoma, the clinical, histological, and biological characteristics overlap significantly with those of nodular-sclerosing Hodgkin lymphoma (NS-HL). Over recent years, the shared biology of these 2 entities has been highlighted in several studies, and mediastinal gray zone lymphoma, with features intermediate between PMBCL and NS-HL, has been recognized as a unique molecular entity. Although there is a lack of consensus about the optimal therapeutic strategy for patients with newly diagnosed PMCBL, highly curative treatment regimens that obviate the need for mediastinal radiation therapy (RT) are favored by most. Recently, the results from IELSG-37 were presented and demonstrated that patients with a negative PET/CT scan at the completion of treatment do not require consolidative RT. Progress in understanding the biology of PMBCL and its close relationship to NS-HL have helped pave the way for the investigation of novel strategies, including immune checkpoint inhibitors (ICI), CD30-targeting agents and adoptive T-cell approaches. Currently, a clinic trial is ongoing that is evaluating the role of nivolumab with chemo-immunotherapy for the frontline treatment of PMBCL, after ICI have shown robust responses in patients with relapsed and refractory (R/R) PMBCL. In the R/R setting, studies with anti-CD19 CAR-T-cell therapies and treatments with bispecific antibodies have shown good activity.

Targeting cancer cells by modulating the immune system has become an important new therapeutic option in many different malignancies. Inhibition of CTLA4/B7 and PD1/PDL1 signaling is now also being investigated and already successfully applied to various hematologic malignancies. A literature review of PubMed and results of our own studies were compiled in order to give a comprehensive overview on this topic. We elucidate the pathophysiological role of immunosuppressive networks in lymphomas, ranging from changes in the cellular microenvironment composition to distinct signaling pathways such as PD1/PDL1 or CTLA4/B7/CD28. The prototypical example of a lymphoma manipulating and thereby silencing the immune system is Hodgkin lymphoma. Also other lymphomas, e.g., primary mediastinal B-cell lymphoma and some Epstein-Barr virus (EBV)-driven malignancies, use analogous survival strategies, while diffuse large B-cell lymphoma of the activated B-cell type, follicular lymphoma and angioimmunoblastic T-cell lymphoma to name a few, exert further immune escape strategies each. These insights have already led to new treatment opportunities and results of the most important clinical trials based on this concept are briefly summarized. Immune checkpoint inhibition might also have severe side effects; the mechanisms of the rather un(der)recognized hematological side effects of this treatment approach are discussed. Silencing the host's immune system is an important feature of various lymphomas. Achieving a better understanding of distinct pathways of interactions between lymphomas and different immunological microenvironment compounds yields substantial potential for new treatment concepts.

Checkpoint inhibitors were a major breakthrough in the field of oncology. In September 2014, based on the KEYNOTE-001 study, the Food and Drug Administration (FDA) approved pembrolizumab, a programmed cell death protein 1 (PD-1) inhibitor, for advanced or unresectable melanoma. Up until now, seven PD-1/PD-ligand(L)-1 inhibitors are approved in various solid cancers and hundreds of clinical studies are currently ongoing. In hematology, PD-1 inhibitors nivolumab and pembrolizumab were approved for the treatment of relapsed/refractory (R/R) classic Hodgkin lymphoma, and later pembrolizumab was approved for R/R primary mediastinal large B-cell lymphoma. In acute myeloid leukemia (AML), the combination of hypomethylating agents and PD-1/PD-L1 inhibitors has shown promising results, worth of further investigation, while other combinations or single agent therapy have disappointing results. On the other hand, rather than in first line, these therapies could be useful in the consolidation or maintenance setting, for achieving minimal residual disease negativity. Furthermore, an interesting application could be the use of PD-1/PD-L1 inhibitors in the post allogeneic hematopoietic stem cell transplantation relapse. There are several reasons why checkpoint inhibitors are not very effective in treating AML, including the characteristics of the disease (systemic, rapidly progressive, and high tumor burden disease), low mutational burden, and dysregulation of the immune system. We here review the results of PD-1/PD-L1 inhibition in AML and discuss their potential future in the management of this disease.

Immune evasion, due to abnormal expression of programmed-death ligands 1 and 2 (PD-L1/PD-L2), predicts poor outcomes with chemoimmunotherapy in diffuse large B-cell lymphoma (DLBCL). Immune checkpoint inhibition (ICI) has limited efficacy at relapse but may sensitise relapsed lymphoma to subsequent chemotherapy. ICI delivery to immunologically intact patients may thus be the optimal use of this therapy. In the phase II AvR-CHOP study, 28 patients with treatment-naive stage II-IV DLBCL received sequential avelumab and rituximab priming ("AvRp;" avelumab 10 mg/kg and rituximab 375 mg/m2 2-weekly for 2 cycles), R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone for 6 cycles) and avelumab consolidation (10 mg/kg 2-weekly for 6 cycles). Grade 3/4 immune-related adverse events occurred in 11%, meeting the primary endpoint of a grade ≥3 irAE rate of <30%. R-CHOP delivery was not compromised but one patient ceased avelumab. Overall response rates (ORR) after AvRp and R-CHOP were 57% (18% CR) and 89% (all CR). High ORR to AvRp was observed in primary mediastinal B-cell lymphoma (67%; 4/6) and molecularly-defined EBV-positive DLBCL (100%; 3/3). Progression during AvRp was associated with chemorefractory disease. Two-year failure-free and overall survival were 82% and 89%. An immune priming strategy with AvRp, R-CHOP and avelumab consolidation shows acceptable toxicity with encouraging efficacy.