Post-transplant Diffuse Large B-cell Lymphoma Research Articles

Pembrolizumab with Rituximab in Relapsed/Refractory Follicular Lymphoma and Diffuse Large B Cell Lymphoma

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.

Characteristics and Outcome of Post-Transplant Lymphoproliferative Disorders After Solid Organ Transplantation: A Single Center Experience of 196 Patients Over 30 Years.

Post-transplant lymphoproliferative disorder (PTLD) is a rare but life-threatening complication after transplantation. In this retrospective, monocentric study we aimed to collect real life data regarding PTLD and determine the role of Epstein Barr Virus (EBV) status and year of diagnosis on prognosis. We identified 196 biopsy-proven PTLD after solid organ transplantation (SOT) diagnosed at the University Hospitals Leuven (Belgium) from 1989 to 2019. EBV status was positive in 61% of PTLD. The median overall survival (OS) was 5.7years (95% CI: 2.99-11.1). Although EBV positivity was not significantly correlated with OS in multivariate analyses (HR: 1.44 (95% CI: 0.93-2.24); p = 0.10), subgroup analysis showed a significantly better median OS for EBV negative post-transplant diffuse large B-cell lymphoma (DLBCL) compared to EBV positive post-transplant DLBCL (8.8 versus 2.5 years respectively; p = 0.0365). There was a significant relation between year of PTLD diagnosis and OS: the more recent the PTLD diagnosis, the lower the risk for death (adjusted HR: 0.962 (95% CI: 0.931-0.933); p = 0.017). In conclusion, the prognosis of PTLD after SOT has improved in the past decades. Our analysis shows a significant relation between EBV status and OS in post-transplant DLBCL.

Identification of distinct subgroups of EBV-positive post-transplant diffuse large B-cell lymphoma

Post-transplantation lymphoproliferative disorder is an aggressive complication of transplantation, most frequently of diffuse large B-cell lymphoma morphology and associated with Epstein–Barr virus (EBV) infection/reactivation. In this study the microenvironment of EBV+ (n=23) and EBV− (n=9) post-transplant non-germinal center B-cell diffuse large B-cell lymphoma was characterized. Of EBV+ cases somatic hypermutation analysis, gene expression profiling, and extensive phenotyping were performed. Our results demonstrated variable cytotoxic T-cell infiltration and significantly increased CD163+ M2 macrophage infiltration in EBV+ compared with EBV− post-transplant diffuse large B-cell lymphoma. On the basis of IgM staining and hypermutation analysis, two EBV+ post-transplant diffuse large B-cell lymphoma subgroups were identified: IgM+ tumors lacking somatic hypermutations and IgM− tumors harboring somatic hypermutations. IgM− tumors arose late following transplantation (median interval: 16 months), mainly in kidney recipients. IgM+ tumors on the other hand arose early (median interval: 3 months, P-value=0.0032), almost exclusively following stem cell transplantation and were associated with worse outcome (median survival 1 month for IgM+versus 41 months for IgM− tumors, log-rank/Wilcoxon P-value 0.07/0.04). Notably, IgM+ tumors were characterized by plasma cell features (monotypic kappa/lambda expression, high MUM1 expression, and partial CD138 expression) and a high proliferation index. Consistent with the plasma cell phenotype, unfolded protein response signaling was upregulated. In contrast, IgM− EBV+ post-transplant diffuse large B-cell lymphoma did not express kappa, lambda, IgD, or CD138 and expressed limited MUM1. In these tumors T-cell signaling was enhanced associated with increased T-cell infiltration compared with IgM+ cases. Overall, our results allow further molecular classification of EBV+ post-transplant diffuse large B-cell lymphoma and provide a rationale for the use of subtype-specific-targeted therapies (eg, bortezomib in IgM+ tumors). Our findings also provide a biological basis for the clinical differences between post-transplant lymphoproliferative disorder following solid organ and stem cell transplantation, which are regarded as different disorders.

Post-Transplant Diffuse Large B Cell Lymphoma with Non Germinal Center B-Cell Subtype Frequently Lacks Programmed Cell Death Ligand (PD-L1) Overexpression Which May Influence Overall Outcomes

Background : Post Transplant Lymphoproliferative disorder (PTLD) represents a distinct and rare complication following solid organ transplantation (SOT). Insight into the biology of this disorder is limited to retrospective reviews and case series. In one of the first reports for post-transplant Diffuse Large B cell Lymphoma (PT-DLBCL) cases, we demonstrated a higher incidence and improved outcomes in PT-DLBCL non-germinal center B-cell (non-GCB) subtype compared to PT-DLBCL germinal center B-cell (GCB) Subtype. Published data suggests immunocompetent DLBCL non-GCB subtypes are less common and fare worse than immunocompetent GCB DLBCL. The reason for this unexpected finding in our PT-DLBCL pts is not fully understood. Recently Kiyasu and colleagues demonstrated that PD-L1 overexpression was significantly associated with non-GCB DLBCL, EBV virus positivity and poor prognosis in immunocompetent DLBCL samples. Therefore based on this we hypothesized that PT-DLBCL non-GCB subtype may have negative PD-L1 overexpression thus possibly accounting for improved outcomes compared to their immunocompetent counterparts. Hence we sought to test PD-L1 expression in our samples with PT-DLBCL.Methods: With IRB approval, we retrospectively identified PT- DLBCL patients treated at the University of Colorado between Jan 1989 to April 2015. We retrieved formalin fixed paraffin embedded PT-DLBCL tissue specimens and determined cell of origin by the Hans Algorithm. We assessed PD-L1 expression by immunohistochemistry. PD-L1 positive PT-DLBCL was defined as 30% of more of the lymphoma cells showing distinct membranous and or cytoplasmic staining. In addition EBER-ISH was performed to assess EBV status.Results: 86 adult SOT pts with PTLD were treated at our institution. 75 of 86 pts (87%) had monomorphic histology. Among monomorphic PTLD, 64% (48 of 75) had DLBCL. The median age at transplantation was 49.5 yrs (5-74 yrs). Median time from SOT to PTLD was 37 mos (1.4-499). The most common transplanted organ included kidney (40%), liver (38%), lung (13%) and heart (9%). 31% had early PTLD (<12mos of SOT) and 69% had late PTLD (>12mos of SOT). 60% were EBV positive. 77% with early PTLD and 49% with late PTLD were EBV positive. Due to a paucity of archived tissue blocks, IHC staining was applied to 32/48 samples with DLBCL. Non-GCB subtype was identified in 75% (24/32) samples and GCB subtype in 25% (8/32) samples.Of the 48 pts with PT-DLBCL histology, PD-L1 stain was performed on 18 samples. Of the 18 PT-DLBCL samples, 77% (14/18) had non-GCB subtype and 16% (3/18) had GCB subtype. PD-L1 expression was negative in 78% (11/14) and positive in 22% (3/14) of non-GCB DLBCL samples. PD-L1 expression was negative in 100% (3/3) of GCB DLBCL samples. The sample size was too small to effectively describe the survival experience of pt subsets. Using Fisher's exact test we found no evidence to support an association between EBV Status and PDL1 expression (p-value 0.316).Conclusions: We previously reported in our consecutive series of PTLD after SOT an increased incidence and improved survival in pts with PT-DLBCL non-GCB subtype (ASH 2015) compared to PT-DLBCL GCB subtype. The reason for this is not fully understood. However, our limited series reveals that a majority of pts with PT- DLBCL non-GCB subtype was negative for PD-L1 overexpression. This might explain the improved outcomes in the PT-DLBCL non-GCB population. Despite a small sample size it is also interesting to note that 100% pts with PT-DLBCL GCB subtype were negative for PD-L1 overexpression. In the era of immunotherapy further studies in larger patient cohorts are warranted in order to understand the unique biology and outcomes of PT-DLBCL since it may have therapeutic implications. DisclosuresPollyea:Celgene: Other: advisory board, Research Funding; Ariad: Other: advisory board; Alexion: Other: advisory board; Pfizer: Other: advisory board, Research Funding; Glycomimetics: Other: DSMB member. Kamdar:Seattle Genetics: Speakers Bureau.

CD30 Expression in Diffuse Large B-Cell Lymphoma (DLBCL) Correlates with Non-GCB Subtype but Does Not Have Prognostic Impact in Patients Treated with First Line R-CHOP/R-CHOP-like

Background: DLBCL is a heterogeneous disease with 30% of patients presenting as refractory/relapsing disease following R-CHOP treatment. Therefore, new prognostic factors to identify the poor-risk population and alternative therapies for them are needed. CD30 is a member of the tumour necrosis factor receptor (TNFR) super family and is expressed by several types of T- and B-cell non-Hodgkin lymphomas. Brentuximab vedotin, an anti CD30 antibody, is used in clinical practice for Hodgkin lymphoma and systemic anaplastic large cell lymphoma. The significance of CD30 expression in DLBCL remains unknown. We aimed to study the expression of CD30 in a large cohort of the novo DLBCL patients homogeneously treated with R-CHOP or R-CHOP-like protocols to evaluate its correlation with clinical and biological characteristics at diagnosis and its impact in clinical outcome.Methods: we prospectively registered 155 patients diagnosed of DLBCL between January 2012 to December 2015 in our center. Twenty-one patients with primary central nervous system DLBCL, transformed lymphoma or post-transplant DLBCL were excluded from the study. Anatomopathology review was performed in all cases, and 14 cases with not enough histological tissue to perform additional staining were also excluded. Immunohistochemistry was performed in 120 cases on 4 microns' paraffin sections using routine protocols,CD30 expression was analyzed using the antibodyCD30 clone BerH2, dilution 1:30; Dako; staining in more than 10% of the malignant cells was considered positive. Samples were classified as germinal center B-cell-like (GCB) vs. non-GCB subtypes by immunohistochemistry according to Hans algorithm. Univariate analyses were assessed by Chi square test. Survival curves were estimated using the Kaplan-Meier method and compared using the log-rank test. Multivariate analyses for progression-free survival (PFS) were assessed Cox proportional hazard regression model.Results: among the 120 cases analyzed, CD30 was expressed in 40 (33.3%). Clinical and biological characteristics at disease presentation are shown in Table 1. The expression of CD30 was significantly higher in the non-GCB subtype cases (p=0.0001). One hundred and six patients were homogeneously treated with R-CHOP (100 patients) or R-CHOP-like (1 R-COMP, 2 Burkitt scheme, 1 GA101-CHOP and 2 R-Bortezomib-CAP), and were included in the outcome analyses. Response rates and survival of this subgroup of patients are shown in Table 2. With a median follow-up of 16.4 months, no differences were found neither in PFS or OS between CD30 positive and CD30 negative patients (Table 2). In the multivariate analyses including the following independent variables: gender, B-symptoms, Bulky mass (>5cm), cell of origin (GCB vs non-GCB), International Prognostic Index (IPI) and CD30 expression, IPI 3-5 was de only factor significantly related with poor PFS (HR 2.92, 95% CI:1.18-7.24, p=0.02).Conclusion: CD30 is expressed in one third of DLBCL patients, in whom an anti-CD30 therapy could be used. CD30 expression is significantly higher in patients with non-CGB DLBCL, however and in our experience, its expression does not influence either response to R-CHOP or R-CHOP- like therapy or survival. [Display omitted] [Display omitted] DisclosuresGonzalez Barca:Gilead: Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Speakers Bureau.

823 - New insights in the molecular pathogenesis of Epstein–Barr virus-positive and -negative post-transplant diffuse large B-cell lymphoma

823 - New insights in the molecular pathogenesis of Epstein–Barr virus-positive and -negative post-transplant diffuse large B-cell lymphoma

EBV-Positive and EBV-Negative Posttransplant Diffuse Large B Cell Lymphomas Have Distinct Genomic and Transcriptomic Features

The molecular pathogenesis of posttransplant diffuse large B cell lymphoma (PT-DLBCL) is largely unknown. We have recently shown that Epstein-Barr virus-positive (EBV(+)) and -negative (EBV(-)) PT-DLBCL have distinct gene expression profiles, and the transcriptomic profile of EBV(-) PT-DLBCL is similar to that of DLBCL in immunocompetent individuals (IC-DLBCL). To validate these observations at the genomic level, we performed array-comparative genome hybridization (aCGH) analysis of 21 EBV(+) PT-DLBCL, 6 EBV(-) PT-DLBCL, and 11 control IC-DLBCL, and subsequently combined genomic and transcriptomic data. The analysis showed that EBV(+) and EBV(-) PT-DLBCL have distinct aCGH profiles and shared only one recurrent imbalance. EBV(-) PT-DLBCL, however, displayed at least 10 aberrations recurrent in IC-DLBCL, among which characteristic gain of 3/3q and 18q, and loss of 6q23/TNFAIP3 as well as 9p21/CDKN2A. The most prevalent aberration in EBV(+) PT-DLBCL was gain/amplification of 9p24.1 targeting PDCD1LG2/PDL2. Our data indicate that the FOXP1 oncogene and the tumor suppressor CDKNA2 implicated in EBV(-) DLBCL, do not play a critical role in the pathogenesis of EBV(+) PT-DLBCL. Altogether, genomic profiling of PT-/IC-DLBCL confirms that EBV(-) and EBV(+) PT-DLBCL are distinct entities, while EBV(-) PT-DLBCL has features in common with IC-DLBCL. These findings support the hypothesis that EBV(-) PT-DLBCL are de novo lymphomas in transplant recipients.

Recent insights in the pathogenesis of post-transplantation lymphoproliferative disorders.

Post-transplant lymphoproliferative disorder (PTLD) is an aggressive complication of solid organ and hematopoietic stem cell transplantation that arises in up to 20% of transplant recipients. Infection or reactivation of the Epstein-Barr virus (EBV), a ubiquitous human herpesvirus, in combination with chronic immunosuppression are considered as the main predisposing factors, however insight in PTLD biology is fragmentary. The study of PTLD is complicated by its morphological heterogeneity and the lack of prospective trials, which also impede treatment optimization. Furthermore, the broad spectrum of underlying disorders and the graft type represent important confounding factors. PTLD encompasses different malignant subtypes that resemble histologically similar lymphomas in the general population. Post-transplant diffuse large B-cell lymphoma (PT-DLBCL), Burkitt lymphoma (PT-BL) and plasmablastic lymphoma (PT-PBL) occur most frequently. However, in many studies various EBV+ and EBV- PTLD subtypes are pooled, complicating the interpretation of the results. In this review, studies of the gene expression pattern, the microenvironment and the genetic profile of PT-DLBCL, PT-BL and PT-PBL are summarized to better understand the mechanisms underlying post-transplantation lymphomagenesis. Based on the available findings we propose stratification of PTLD according to the histological subtype and the EBV status to facilitate the interpretation of future studies and the establishment of clinical trials.

Single nucleotide polymorphism‐arrays provide new insights in the pathogenesis of post‐transplant diffuse large B‐cell lymphoma

Post-transplant lymphoproliferative disorders (PTLD) are complications of solid organ transplantation associated with severe morbidity and mortality. Diffuse large B-cell lymphoma (DLBCL) represents the most common form of monomorphic PTLD. We studied 44 cases of post-transplant DLBCL (PT-DLBCL) with high-density genome wide single nucleotide polymorphism-based arrays, and compared them with 105 cases of immunocompetent DLBCL (IC-DLBCL) and 28 cases of Human Immunodeficiency Virus-associated DLBCL (HIV-DLBCL). PT-DLBCL showed a genomic profile with specific features, although their genomic complexity was overall similar to that observed in IC- and HIV-DLBCL. Among the loci more frequently deleted in PT-DLBCL there were small interstitial deletions targeting known fragile sites, such as FRA1B, FRA2E and FRA3B. Deletions at 2p16.1 (FRA2E) were the most common lesions in PT-DLBCL, occurring at a frequency that was significantly higher than in IC-DLBCL. Genetic lesions that characterized post-germinal center IC-DLBCL were under-represented in our series of PT-DLBCL. Two other differences between IC-DLBCL and PT-DLBCL were the lack of del(13q14.3) (MIR15/MIR16) and of copy neutral LOH affecting 6p [major histocompatibility complex (MHC) locus] in the latter group. In conclusion, PT-DLBCL presented unique features when compared with IC-DLBCL. Changes in PT-DLBCL were partially different to those in HIV-DLBCL, suggesting different pathogenetic mechanisms in the two conditions linked to immunodeficiency.

Subgroups of Diffuse Large B-Cell Lymphoma (DLBCL) with Different Genomic Lesions and Clinical Course During Treatment with R-CHOP.

Abstract 3957Poster Board III-893 BACKGROUNDDespite recent therapeutic improvements, the clinical course of DLBCL still differs considerably among patients. Here, we present the final results of a study to identify distinct DLBCL subgroups in patients treated with R-CHOP. METHODSDNA from 166 frozen DLBCL samples (PMBL,HIV-related DLBCL, post-transplant DLBCL and Richter's Syndromes were excluded) was analyzed with Affymetrix Human Mapping 250K arrays. Affymetrix U133 PLUS 2.0 gene expression profiles (GEP) were available for 54 cases. An optimized non-negative matrix factorization (NMF) was used for unsupervised clustering. The impact of the recurrent lesions on OS, PFS and DFS was evaluated with the log-rank test followed by multiple test correction (MTC). RESULTS20 lesions showed a statistical significant impact on OS. Only 8p23.1 loss maintained its significance after MTC and was associated with additional aberrations, such as 17p- and 15q-. Unsupervised clustering identified 5 clusters with distinct genetic profiles, clinical characteristics and outcome: 1 (61/166, 37%), 2 (22/166, 13%), 3 (5/166, 4%), 4 (29/166, 17%), 5 (7/166, 6%). Cluster 1 was characterized by a heterogeneous genomic profile, lacking the most recurrent lesions. When compared to cluster 2 and 4, there were more HCV infections (9/38, 24% vs 1/12, 8% and 0/20; p=0.014) and bone marrow involvement (16/57, 28% vs 1/19, 5% and 2/24, 8%; p=0.008). GEP and morphology data suggested that cluster 1 could represent DLBCL with a high content of infiltrating T-cells, partially explaining the low rate of aberrations. This cluster has characteristics similar to the “host response” cluster previously identified by Monti et al., 2005. The outcome was poor with a high relapse rate (13/49, 26%) and a 5-yr OS of 76%. Cluster 2 (1q+/3q+/6q-/17p-) had also a relatively poor OS 80%. Cluster 4 (7+/12+) had a good outcome with a 5-yr OS of 92%. Clusters 2 and 4 showed differences in the number of pts with a high IPI-score (9/16, 56% vs. 7/26, 27%; p=0.057) and in single IPI factors, CR-rate (17/22, 77% vs. 25/29, 86%) and relapse rate (5/17, 29% vs. 2/25, 8%; p= 0.068). Cluster 3 (6q-/9-/11q+) had a trend for a good outcome. Instead, cluster 5 (3q+/11q+/18q+/6q-/8p-/15q-/17p-) showed a poor outcome. Clusters 2 and 4 were similar to ABC and GCB, respectively. CONCLUSIONSArrayCGH provides the capability to identify genetic features and clusters, associated with a different outcome in patients treated with R-CHOP. The 8p23.1 locus should be investigated further for a gene that may be important in the pathogenesis of DLBCL. Disclosures:No relevant conflicts of interest to declare.