Diffuse Large B-cell Lymphoma Cohort Research Articles

HIV infection and ART exposure impact tumor T-cell receptor repertoire of diffuse large B-cell lymphoma.

The most common subtype of lymphoma globally, diffuse large B-cell lymphoma (DLBCL) is a leading cause of cancer death in people with HIV (HIV+). The restructuring of the T-cell compartment due to HIV infection and antiretroviral therapy (ART) may have implications for modern treatment selection, but current understanding of these dynamic interactions is limited. Here, we investigated the T-cell response to DLBCL by sequencing the T-cell receptor (TCR) repertoire in a cohort of HIV-negative (HIV-), HIV+/ART-experienced and HIV+/ART-naïve DLBCL patients. HIV+/ART-naïve tumor TCR repertoires were more clonal and more distinct from each other than HIV- and HIV+/ART-experienced. Further, increased overlap between tumor and blood TCR repertoires was associated with improved survival and HIV/ART status. Our study describes TCR repertoire characteristics for the first time in an African DLBCL cohort and demonstrates contributions of HIV infection and ART exposure to the DLBCL TCR repertoire.

Polatuzumab vedotin, venetoclax, and an anti-CD20 monoclonal antibody in relapsed/refractory B-cell non-Hodgkin lymphoma.

The Phase 2 portion of this study evaluated safety and efficacy of polatuzumab vedotin 1.8 mg/kg and venetoclax 800 mg, plus fixed-dose obinutuzumab 1000 mg or rituximab 375 mg/m2 in patients with relapsed/refractory (R/R) follicular lymphoma (FL) or diffuse large B-cell lymphoma (DLBCL), respectively. Patients with complete response (CR) or partial response (PR)/stable disease (FL) or CR/PR (DLBCL) at end of induction (EOI; six 21-day cycles) received post-induction therapy with venetoclax and obinutuzumab or rituximab, respectively. Primary endpoint was CR rate at EOI. Safety-evaluable populations included 74 patients (FL cohort; median age 64 years; progression of disease within 24 months on first-line treatment, 25.7%; FL International Prognostic Index 3-5, 54.1%; ≥2 previous therapies, 74.3%) and 57 patients (DLBCL cohort; median age 65 years; International Prognostic Index 3-5, 54.4%; ≥2 previous therapies, 77.2%). The most common non-hematologic adverse events (mostly Grades 1-2) in the FL and DLBCL cohorts were diarrhea (55.4% and 47.4%, respectively) and nausea (47.3% and 36.8%); neutropenia was the most common Grades 3-4 toxicity (39.2% and 52.6%). Efficacy-evaluable populations included patients treated at the recommended Phase 2 dose (FL, n = 49; DLBCL, n = 48). CR rates at EOI were 59.2% (FL) and 31.3% (DLBCL); median progression-free survival was 22.8 months (95% confidence interval [CI], 14.5-not evaluable) and 4.6 months (95% CI, 3.6-8.1), respectively. Polatuzumab vedotin plus venetoclax and obinutuzumab/rituximab had acceptable safety in patients with R/R FL or DLBCL, with promising response rates in R/R FL, including high-risk patients.

Spatially-resolved transcriptomics reveal macrophage heterogeneity and prognostic significance in diffuse large B-cell lymphoma

Macrophages are abundant immune cells in the microenvironment of diffuse large B-cell lymphoma (DLBCL). Macrophage estimation by immunohistochemistry shows varying prognostic significance across studies in DLBCL, and does not provide a comprehensive analysis of macrophage subtypes. Here, using digital spatial profiling with whole transcriptome analysis of CD68+ cells, we characterize macrophages in distinct spatial niches of reactive lymphoid tissues (RLTs) and DLBCL. We reveal transcriptomic differences between macrophages within RLTs (light zone /dark zone, germinal center/ interfollicular), and between disease states (RLTs/ DLBCL), which we then use to generate six spatially-derived macrophage signatures (MacroSigs). We proceed to interrogate these MacroSigs in macrophage and DLBCL single-cell RNA-sequencing datasets, and in gene-expression data from multiple DLBCL cohorts. We show that specific MacroSigs are associated with cell-of-origin subtypes and overall survival in DLBCL. This study provides a spatially-resolved whole-transcriptome atlas of macrophages in reactive and malignant lymphoid tissues, showing biological and clinical significance.

The impact of MYD88 and PIM1 in mature large B-cell non-Hodgkin lymphomas: Defining element of their evolution and prognosis.

Sequence studies of the entire exome and transcriptome of lymphoma tissues have identified MYD88 and PIM1 as involved in the development and oncogenic signaling. We aimed to determine the frequency of MYD88 and PIM1 mutations, as well as their expressions in conjunction with the clinicopathological parameters identified in mature large B-cell non-Hodgkin lymphomas. The ten-year retrospective study included 50 cases of mature large B-cell lymphoma, diagnosed at the Pathology Department of the Emergency County Hospital of Constanţa and Săcele County Hospital of Brasov. They were statistically analyzed by demographic, clinicopathological, and morphogenetic characteristics. We used a real-time polymerase chain reaction technique to identify PIM1 and MYD88 mutations as well as an immunohistochemical technique to evaluate the expressions of the 2 genes. Patients with lymphoma in the small bowel, spleen, brain, and testis had a low-performance status Eastern Cooperative Oncology Group (P = .001). The Eastern Cooperative Oncology Group performance status represented an independent risk factor predicting mortality (HR = 9.372, P < .001). An increased lactate dehydrogenase value was associated with a low survival (P = .002). The international prognostic index score represents a negative risk factor in terms of patient survival (HR = 4.654, P < .001). In cases of diffuse large B-cell lymphoma (DLBCL), immunopositivity of MYD88 is associated with non-germinal center B-cell origin (P < .001). The multivariate analysis observed the association between high lactate dehydrogenase value and the immunohistochemical expression of PIM1 or with the mutant status of the PIM1 gene representing negative prognostic factors (HR = 2.066, P = .042, respectively HR = 3.100, P = .004). In conclusion, our preliminary data suggest that the oncogenic mutations of PIM1 and MYD88 in our DLBCL cohort may improve the diagnosis and prognosis of DLBCL patients in an advanced stage.

Health-Related Quality of Life and Symptoms in Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma Treated with Odronextamab Monotherapy in the Phase 2 ELM-2 Study

Background. Patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) have poor prognosis and significant impairment of health-related quality of life (HRQoL). CD20xCD3 bispecific antibodies show promise in the management of R/R DLBCL. ELM-2 (NCT03888105), a Phase 2, open-label, multicohort, multicenter study of the CD20xCD3 bispecific antibody odronextamab, demonstrated deep and durable responses and generally manageable safety in patients with R/R DLBCL. We report herein, for the first time, patient-reported outcome (PRO) results for patients in the R/R DLBCL cohort in ELM-2. Methods. In ELM-2, patients with R/R DLBCLafter 2 or more prior lines of therapy received odronextamab IV weekly in 21-day cycles in Cycles (C) 1-4. Revisions to the step-up dosing regimen to mitigate cytokine release syndrome (CRS) were reported previously. Odronextamab was administered with steroid prophylaxis and step-up doses of 0.7/4/20 mg in C1, then 160 mg on Days 1, 8, and 15 of C2-4 (the DLBCL 160 mg cohort). After C4, odronextamab maintenance treatment continued at 320 mg every 2 weeks until disease progression or unacceptable toxicity. Patients with durable complete response for ≥9 months transitioned to dosing every 4 weeks. PRO data were collected via the FACT-Lym, EORTC QLQ-C30, and EQ-5D-3L questionnaires at Weeks 1 (baseline), 2, 3, 4, and 10, then every 8 weeks in the first year and every 12 weeks in the second year. Pre-specified PRO analyses reported here are FACT-Lym lymphoma symptoms (LymS), FACT-G total, Trial Outcome Index (TOI), FACT-Lym total, EORTC QLQ-C30 general health status/quality of life (GHS/QoL), and EQ-5D-3L visual analog scale (VAS). PRO longitudinal analysis using mixed models for repeated measures (MMRM) were conducted through Week 42, the last visit with ≥10 patients with PRO data, and changes from baseline were statistically significant if the 95% confidence interval did not contain zero. No adjustment for multiplicity was performed, hence all statistical significance is nominal. Published ranges for minimum important difference (MID) for clinically meaningful thresholds are: GHS/QoL, 10; LymS, 2.9-5.4; FACT-G total, 3-7; TOI: 5.5-11; FACT-Lym total, 6.5-11.2; and EQ-5D-3L VAS, 7-12. Responder analysis and time to definitive deterioration (TTDD) used the upper end of these MID ranges to define clinically meaningful changes. Results. The final analysis of the DLBCL 160 mg cohort in ELM-2 assessed 141 patients. Median age was 66.0 (range, 24-88) years, with 56.0% ≥65 years, 59.6% male, 43.3% White, 47.5% Asian, 32.6% ECOG=0, and 67.4% ECOG=1. Median duration of follow-up was 26.2 (range, 8.5-34.3) months. PRO completion rates for FACT-Lym, EORTC QLQ-C30, and EQ-5D-3L were high at baseline and for most assessments through Week 42. Patients reported statistically significant and clinically meaningful improvements from Weeks 10 through 42 for FACT-Lym LymS (Figure), and from Weeks 18 through 42 for FACT-G total, FACT-Lym TOI, and FACT-Lym total (except Week 34 for FACT-G total and FACT-Lym total). Additionally, patients reported statistically significant and clinically meaningful improvements for EORTC QLQ-C30 GHS/QoL at Week 42, and for EQ-5D-3L VAS at Week 26. In responder analyses, the proportion of patients reporting clinically meaningful improvement or stability was higher than the proportion reporting meaningful worsening at each assessment through Week 42 for all scales/summary scores. Median TTDD was not reached for FACT-Lym LymS, FACT-Lym TOI, or EQ-5D-3L VAS. Conclusions. In the Phase 2 ELM-2 study, patients with R/R DLBCL reported favorable HRQoL during odronextamab treatment; patient-reported symptoms, functioning, and overall quality of life were maintained or improved from baseline through Week 42. Odronextamab treatment until disease progression may have benefits on HRQoL for heavily pretreated patients with R/R DLBCL and potentially addresses unmet needs in a challenging treatment setting. Collection of PROs was consistently high and the results offer important patient-centered insights into the overall benefit-risk profile of odronextamab in R/R DLBCL.

Early Identification of Refractory/Relapsed Diffuse Large B Cell Lymphoma with Serial Ctdna Sampling

Background: Diffuse Large B Cell Lymphoma (DLBCL) is an aggressive lymphoma that is curable in 60% of patients with chemoimmunotherapy. Outcomes are poor for those experiencing relapsed or refractory disease (rrDLBCL), particularly for patients with primary refractory disease (REFR, &amp;lt; 9 months from diagnosis) and early relapse (ER, 9 months to 2 years from diagnosis). Some of these patients would be candidates for chimeric antigen receptor T cell therapy (CART) in second line, where outcomes are superior when the disease burden is low. Therefore, exploring strategies to identify these high-risk patients early is important. Plasma circulating tumor DNA has been shown to be prognostic in various DLBCL cohorts. Method: We developed a custom panel of 170 genes to identify early treatment failure in a cohort of 171 patients that had profiling performed on 323 plasma samples. Plasma samples were taken serially starting at diagnosis and as patients progressed through frontline treatment. All plasma samples underwent DNA extraction, library preparation and subsequent sequencing using a panel of DLBCL related genes at high read depth (~1000x). Single nucleotide variant (SNV) calling was carried out using a custom pipeline including paired normal DNA for improved somatic variant detection. ctDNA fraction was estimated based on the highest variant allele fraction detected, using a loss of heterozygosity somatic model. Our ctDNA analysis focused on samples at diagnosis, cycle 2 of therapy, and end of treatment in order to identify early determinants of refractory disease. Changes in ctDNA levels between time points were represented as log2 ratio of ctDNA fraction. Results: rrDLBCL cases were separated into 3 categories based on the time between diagnosis and progressive disease (PD): 47 REFR, 34 ER, and 31 late relapse (LR, &amp;gt;24 months). The remaining patients were disease free after frontline therapy for over 24 months (CR, n=59), resulting in a cohort enriched for rrDLBCL (65% of cases). The average international prognostic index (IPI) of each group at diagnosis was REFR=3.38, ER=2.87, LR=2.81, and CR=2.41. Cell of Origin, as determined by Hans algorithm, showed a higher number of non-GCB samples in ER and LR groups (53% and 60%, respectively) while REFR and CR displayed increased GCB cases (63% and 66%, respectively). The REFR patients were significantly more likely to be of a 4/5 IPI score at diagnosis than other groups (p=0.0203). Progression-free survival (PFS2) at relapse therapy for REFR (median=0.29 years) was shorter when compared to both ER (p=0.0104, median=0.44 years) and LR (p=0.0012, median=0.80 years). Using the diagnostic plasma sample, there was no significant difference in ctDNA fraction in any of the three groups. When the sample with the highest ctDNA fraction was compared between patients, REFR had significantly higher levels than LR and CR, consistent with a higher overall tumor burden (p=0.001 and 0.026, respectively). There was a trend towards higher ctDNA fraction at the end of treatment in both REFR and ER groups. As ctDNA dynamics are known to be informative of molecular response, we compared patients using the change in ctDNA fraction at cycle 2 of therapy (log2 ratio). This value was significantly different in REFR patients (p=0.0073 vs ER), consistent with a lower rate of molecular response to treatment. Conclusions: While refractory and later relapsed DLBCL have similar ctDNA features at diagnosis, we find they have distinct ctDNA dynamics during treatment. REFR had higher maximal ctDNA levels across time points and both REFR and ER patients exhibited higher levels of ctDNA at end of treatment. Moreover, patients with minimal change in ctDNA levels at cycle 2 of therapy are at a high risk of treatment failure and refractory disease. Further exploration of the specific mutational patterns is ongoing. These results could enable the earlier identification of rrDLBCL and facilitate the prioritization of approaches for therapeutic intervention in rrDLBCL.

Copanlisib in Combination with Rituximab and Bendamustine for Transplant-Ineligible Relapsed/Refractory Diffuse Large B-Cell Lymphoma Patients: Results from the Phase II Multicenter Fil_Copa-Rb Trial from Fondazione Italiana Linfomi (FIL)

Background: 60% of Diffuse large B-cell lymphoma (DLBCL) are cured with R-CHOP. Treatment options for relapsed/refractory (R/R) patients (pts) not eligible to high-dose chemotherapy and autologous stem cell transpntation (ASCT) or CAR-T are limited with short-lasting efficacy. The PI3-K inhibitor copanlisib showed activity in B-cell lymphomas including DLBCL. We reported the results of the phase II single arm multicenter FIL Copa-RB trial which investigated the combination copanlisib plus rituximab and bendamustine (copa-RB) in transplant-ineligible R/R DLBCL. Methods: Patients with R/R DLBCL previously treated with 1-3 prior lines, not eligible to ASCT and CAR-T were enrolled to receive 6 cycles of copa-RB q28 days (induction treatment schedule: copanlisib 60 mg i.v. days 1,8,15. Rituximab 375 mg/m2 i.v. day 1, Bendamustine 90 mg/m2 i.v. days 1,2). Patients with at least stable disease continued with a maintenance phase up to 12 q28 day cycles of Copanlisib (60 mg i.v. days 1,15). The primary end point was 12-month progression free survival (PFS) with an expected improvement from 20% to 35% and a calculated sample size of 81 pts. Results: From 11/2019 to 7/2022, 37 pts were enrolled. Median age was 76 years (68-87), 23 (62%) were at IPI ≥3, 25 (68%) had stage IV, 23 (62%) and 14 (38%) received 1 and 2 prior lines and 35% were refractory to the last treatment. The best overall response rate (ORR) was 51%, with 22% CR. With a median follow-up of 12 months, the 12-mo PFS was 25.2% (95%CI:13.6-38.5%) and median PFS 5.5 months (95%CI:3.7-10.0). The 12-mo overall survival (OS) was 49.4% (95%CI:30.7-65.7%) (fig. 1). Nine patients were alive and in continuous response at time of the data cut-off. 91% of the patients experienced grade &amp;gt; 2 adverse events (AE): neutropenia (58%), infections (28%), gastrointestinal (19%), skin (16%) and thrombocytopenia (13%). SARS-COV-2 infection occurred in 19% with 5 deaths. CMV reactivation occurred in 47%, but without infection. Febrile neutropenia was recorded in 2.8%. AEs led to dose interruptions in 19%. Since the slow recruitment, the unfavorable safety profile and the emerging of potentially more effective new treatment options in this setting of patient, the study was interrupted prematurely by steering committee decision. Conclusions: Copa-RB study was conducted in a difficult-to treat R/R DLBCL cohort (elderly, advanced stage) during COVID pandemic that affected its management. Copa-RB induced a good ORR, but it was short lasting with unfavorable safety profile, so the overall activity was modest and did not support further the development of this combination in this setting of patients. A subset of patients had a long-lasting response. A mutational study is ongoing to identify molecular pathways potentially predictive of response to the combination

CD79 Expression Is Associated with Cell-of-Origin and Outcome in Diffuse Large B-Cell Lymphoma

Introduction: CD79B is a target of polatuzumab vedotin, an antibody-drug conjugate, which significantly improved the prognosis of both previously untreated and relapsed/refractory patients with diffuse large B-cell lymphoma (DLBCL). However, the biological and clinical significance of CD79B protein and gene expression have not been fully explored in DLBCL, thus we aimed at examining these relationships. Methods: We retrospectively analyzed de novo DLBCL patients, who were diagnosed and received rituximab-based immunochemotherapy from 2008 through 2018 in the Okayama Hematology Study Group from Japan. Immunohistochemistry (IHC) staining was performed using a CD79B antibody (AT107-2), and protein expression was assessed based on H-score as described in a previous study (Sehn LH et al. JCO 2020), integrating with publicly available representative bulk RNA sequencing DLBCL datasets (BCC cohort from Ennishi D et al. JCO 2019 and NCI cohort from Schmitz R et al. NEJM 2018). We also performed CD8 and MHC class-I IHC to evaluate the tumor microenvironment. Gene expression profile-based cell-of-origin (COO) classification was performed including double-hit signature (DHITsig), recently renamed the dark zone signature (DZsig), using the NanoString DLBCL90 assay. In addition, simultaneous epitope and transcriptome measurement in single cells from lymphoid tissues was conducted. Results: CD79B IHC was evaluable in 576 cases. DLBCL90 assay classified the entire cohort into 293 ABC (50.9 %), 189 GCB (32.8 %), 31 DZsig-positive (5.4 %) and 63 unclassified (10.9 %). Furthermore, we dichotomized the cohort into 288 CD79B high cases and 288 CD79B low cases according to the median CD79B H-score. A dynamic range of CD79B protein expression was observed across COO, where ABC-DLBCL showed the lowest values followed by GCB-DLBCL and DZsig-positive-DLBCL, in ascending order (Kruskal-Wallis test, P &amp;lt; .00001; Figure A). Indeed, CD79B low cases were significantly enriched in ABC-DLBCL (58 %) compared to GCB-DLBCL (26 %) and DZsig-positive-DLBCL (2 %), respectively (Chi-squared test, P &amp;lt; .001). Consistently, we revealed that CD79B expression was the lowest in ABC-DLBCL compared to GCB-DLBCL and DZsig-positive-DLBCL at the transcriptomic level (Kruskal-Wallis test, P = .011 for BCC cohort and P = .022 for NCI cohort). In addition, we identified different CD79B staining patterns, composed of 433 with cytoplasmic pattern (75 %), 86 with membranous pattern (14.9 %), and 52 cases being IHC negative. These patterns significantly varied across COO (Fisher's exact test, P = .015) and CD79B H-score was the highest in the membranous pattern followed by the cytoplasmic pattern (Kruskal-Wallis test, P &amp;lt; .0001). Of note, the composition of CD8 positive T-cells in CD79B low tumors was significantly higher than that of CD79B high tumors (Wilcoxon rank sum test, P &amp;lt; .0001). However, MHC class-I expression was decreased in CD79B low cases compared to CD79B high (Wilcoxon rank sum test, P = .0002), suggesting an immune escape mechanism with downregulation of MHC class-I in the presence of cytotoxic T-cells, which is often seen in solid cancers. Significant association of CD79B expression with COO further prompted us to evaluate CD79B expression in normal germinal center B cells. Notably, the single-cell simultaneous epitope and transcriptome analysis (CITEseq, n = 2) and single-cell RNAseq analysis (n = 6) of reactive lymph nodes revealed that both CD79B gene and protein expression were the lowest in cells exhibiting plasmablastic signatures, followed by light zone and dark zone B cells (Kruskal-Wallis test, P &amp;lt; .0001; Figure B), supporting the relation of CD79B expression to COO subtype in DLBCL. Regarding prognostic impact, CD79B low group had significantly poorer prognosis in the entire DLBCL cohort (Log-rank test, P = .0005 for overall survival (OS) and P = .008 for progression-free survival (PFS)) and in ABC-DLBCL (Log-rank test, P = .003 for OS and P = .031 for PFS). Moreover, CD79B protein expression was significantly associated with OS after adjusting for International Prognostic Index in the entire DLBCL cohort (Cox regression model; P = .035). Conclusion: Our study identifies distinct CD79B expression patterns across COO subtypes, with CD79B low cases enriched in ABC-DLBCL and demonstrating poorer prognosis, suggesting its potential as a prognostic marker and for targeted therapies.

Optimizing Circulating Tumor DNA Limits of Detection for DLBCL during First Line Therapy

Background: Circulating tumor DNA (ctDNA) assessment is effective in diffuse large B-cell lymphoma (DLBCL) monitoring and risk stratification, with prognostic utility throughout first-line (1L) therapy. DLBCL ctDNA assays vary in analytical sensitivity, or limit of detection (LOD), which range from parts per thousand to below 1 part per million (1 in 10 6). With differing assays and time-points assessed in DLBCL studies, the relationship between analytical and clinical sensitivity for outcome prediction remains unclear. We assessed the prognostic ability of ctDNA at various LODs and used modeling strategies to project the efficacy of assays for minimal residual disease (MRD) detection. Methods: We previously reported a DLBCL dataset assessing plasma ctDNA before, during and after curative-intent 1L anthracycline-based treatment from multiple prospective studies, including RCHOP or EP[O]CH with acalabrutinib, lenalidomide, obinutuzumab, and polatuzumab (Roschewski et al. ASH 2022). In this study, ctDNA was evaluated by Phased Variant Enrichment Detection and Sequencing (PhasED-Seq, Foresight Diagnostics), a ctDNA MRD assay with LOD below 1 in 10 6. Samples from this study and a prospective DLBCL cohort treated with standard 1L therapy at Samsung Medical Center were considered in this analysis. We assessed the prognostic ability of ctDNA detection, considering LODs from 1 in 100 (10 2)to 1 in 10 6 to predict progression free survival (PFS) before, during and after 1L treatment. We assessed the desired sensitivity for ctDNA MRD during treatment by generating patient-specific log-linear models assuming exponential decay. We projected the distribution of variant allele frequencies (VAFs) during therapy from cycles 2 to 5 for patients who progressed to determine the minimal acceptable analytical sensitivity. Results: We included 230 patients consisting of 588 ctDNA samples, with 201 before therapy, 71 at C2D1, 101 at C3D1, 70 at C4D1 and 145 at end of therapy (EOT). Median follow-up was 17.5 months and 62 patients (27%) progressed. To evaluate the impact of LOD at treatment milestones, we applied a threshold for ctDNA positivity ranging from 1 in 10 2 to 1 in 10 6. Increased LOD had no effect on the performance of ctDNA before therapy (Figure A &amp; B). At C2D1, if the LOD was at least 1 in 10 4, there was no difference in MRD prognostic performance. Starting at C3D1, improving the LOD for ctDNA positivity down to 1 in 10 6 showed superior predictive power for PFS at 24 months. The power of ctDNA to predict PFS at 24 months improved later in therapy, with area under the receiver operator curves (AUROCs) for PFS24 of 0.68, 0.73, 0.77, 0.88, and 0.86, at pretreatment, C2D1, C3D1, C4D1, and EOT time-points respectively (Figure A). To further understand the desired LOD for ctDNA MRD, we developed personalized models of ctDNA VAFs. Exponential models fit the data well in 43/44 cases with ≥ 3 MRD-detectable samples through C4D1, with a median correlation of 0.91, confirming their utility for modeling ctDNA. We generated log-linear models for 106 patients with ≥ 2 MRD-detectable samples, and used log-fold change in VAF per cycle (i.e. the slope) to compare patients by progression. Median log-fold change in VAF per cycle was worse for patients who progressed at -1.1 (IQR -1.4, -0.7) compared to those who remained disease-free with median -1.5 (IQR -2.0, -1.1) (p&amp;lt;0.0001). Patients with primary refractory DLBCL on EOT imaging had less robust log-fold change per cycle with median of -0.9 (IQR -1.3, -0.5) compared to those who relapsed after CR with median -1.3 (IQR -1.7, -0.9) (p=0.0004). We used the distribution of slopes to project VAFs for cycles 2 to 5 for patients who progressed to determine the LODs that provide acceptable clinical sensitivity. We found the analytical sensitivity for detecting DLBCL extended lower for each cycle, demonstrating the need for a LOD at least 1 in 10 6 for robust MRD detection at late time-points during 1L treatment. Conclusion: When using an ultrasensitive assay, MRD assessment at later timepoints better predicts PFS than at early timepoints. While the technical LOD does not affect disease burden assessment before therapy, using more sensitive assays during and after therapy improves disease detection and outcome prediction. Utilizing the most sensitive ctDNA MRD assays in 1L DLBCL therapy will maximize the efficacy of MRD-driven therapeutic strategies and MRD as a surrogate endpoint in future trials.

Whole Exome Sequencing Analysis of Diffuse Large B-Cell Lymphoma That Progressed to Central Nervous System

Background: Recent sequencing analyses have identified distinct genetic subtypes of diffuse large B-cell lymphoma (DLBCL). The MCD subtype, characterized by MYD88 L265P and CD79B gene mutations, is frequently found in DLBCL that progresses to the central nervous system (CNS), known as secondary CNS lymphoma (sCNSL) (Ollila, Blood 2021). In addition, the MCD subtype is also frequently found in primary CNS lymphoma (PCNSL) (Radke, Nat commun 2022). Therefore, we hypothesized that specific genetic alterations that are present in the initial DLBCL tumors are associated with their progression to the CNS. We aimed to investigate i) the clinical impact of genetic subtypes of DLBCL and ii) genomic mutations that may be associated with sCNSL. To this end, genetic alterations in DLBCL samples at diagnosis that later developed into sCNSL were evaluated using whole-exome sequencing (WES). Methods: A total of 44 patients with DLBCL who developed sCNSL after receiving standard rituximab-containing chemotherapy between 2009 and 2020 were identified from five institutions. sCNSL was diagnosed on the basis of imaging and/or pathological findings. Genomic DNA (gDNA) was extracted from formalin-fixed, paraffin-embedded tumor samples obtained at the initial diagnosis of DLBCL. Finally, 26 of the 44 samples with sufficient gDNA were subjected to WES at BGI Genomic Co. Ltd. Single-nucleotide variants and short indels were detected using Mutect2 and filtered as described in Figure 1. Genetic subtypes were determined using the LymphGen algorithm (https://llmpp.nih.gov/lymphgen/index.php). The association between the clinicopathological features and genetic subtypes was also evaluated. In addition, recurrently mutated genes (&amp;gt;10% in our cohort) were identified and their alteration frequencies were compared with those in a representative general DLBCL cohort (N=574, available in the article by Schmitz, NEJM 2018) and PCNSL cohort (N=30, whole genome sequencing performed, available in the article by Radke, Nat Commun 2022) (Figure 1a). Results: The median age of the 26 patients was 69 years (range, 34-87). At the time of CNS progression, 54, 27, and 19% of the patients had parenchymal CNS disease, extraparenchymal CNS disease, and both, respectively. Immunohistological analysis showed that the non-germinal center B-cell-like (GCB) type, as defined using the Hans algorithm, and dual expression of MYC and BCL2 (DEL) were identified in 65% and 69% of patients, respectively. The median overall survival (OS) from CNS relapse was 16 months (95% confidence interval, 2-30). WES analysis showed that the median mean coverage depth of the 26 samples was 140 (range, 53-299). The median mapping rate was 94% (range, 80-99). As expected, the most frequently mutated genes in our cohort were MYD88 (50%), PIM1 (50%), BTG2 (31%), and CD79B (31%), corresponding to the MCD subtype. The LymphGen algorithm classified the 26 samples into MCD (n=12, 46%), EZB (n=5, 19%, including one with a composite feature of ST2), BN2 (n=1, 4%) and “not classified” (n=8, 31%) (Figure 1b). The CNS-IPI risk, DEL status, and CNS relapse sites did not differ among the genetic subgroups. In addition, univariate analysis showed that non-GCB status, DEL status, and genetic subtype at initial diagnosis did not influence OS. Next, we shortlisted 38 genes whose mutations were identified in three or more samples (&amp;gt;10%) of our cohort as well as in &amp;gt;10% of the PCNSL cohort (by Radke, Nat Commun 2022). We further selected genes that were less frequent (&amp;lt;3%) in the general DLBCL cohort and identified several genes, such as MUC16 and FAT4, that were more enriched in PCNSL and our sCNSL cases (Figure 1a). Metascape analysis (https://metascape.org/gp/index.html#/main/step1) revealed that the top three enriched processes associated with these genes were sensory organ development, cell adhesion via plasma membrane adhesion molecules, and morphogenesis of epithelium. Conclusion: Our study confirmed that MCD was a major genetic subtype of DLBCL that developed sCNSL. We identified recurrently mutated genes that were common in both sCSNL and PCNSL but not in the general DLBCL cohort; these genes may be associated with CNS progression. Validation of our results and investigation of the functions of these genes will help to understand the mechanisms of CNS relapse and develop more accurate markers to predict sCNSL. *Suzuki T and Yokomori R equally contributed to this study.

Tumor-Infiltrating Normal B Lymphocytes Have Remarkable Prognostic Effects and Are Crucial for Antitumor Immune Responses in Diffuse Large B-Cell Lymphoma

Introduction: In recent years, increasing evidence suggests an important role of tumor-infiltrating B lymphocytes (TIL-Bs) in cancer immunity. In various types of solid tumors, high density of TIL-Bs and presence of mature tertiary lymphoid structures consistently correlate with better prognosis and response to immune checkpoint blockade therapies. Diffuse large B-cell lymphoma (DLBCL) is a type of aggressive lymphoma arising from mature B cells. TIL-Bs have been identified in DLBCL based on single-cell gene-expression data in several previous studies, but their prognostic significance in DLBCL is unknown. In this study, we determined the clinical significance of TIL-B abundance and investigated the potential underlying mechanisms. Patients and Methods: This abstract includes a discovery study in which we distinguished TIL-Bs from malignant B-cells by immunoglobulin gene (IG) clonotype analysis and a validation study using flow cytometry. In the discovery study, a molecularly well-characterized DLBCL cohort assembled by the International DLBCL R-CHOP Consortium Program was analyzed. DNA samples from DLBCL patients were sequenced by high-throughput ultra-deep sequencing assays using multiplexed forward and reverse primers. Based on the IG heavy chain (IGH) sequencing results, malignant B-cell and TIL-B VDJ clonotypes were identified for 138 patients, and the frequencies and numbers of TIL-B clonotypes in individual sequence repertoires were calculated. In 79 DLBCL cases, a DJ-only sequence was predominant and no productive VDJ sequences met the criteria for diagnostic sequences. Total frequencies of productive VDJ sequences in the sequence repertoires were then used to access high and low TIL-B frequencies. TIL-B frequencies were also evaluated by IG light chain clonotypes for these 217 patients and additional 52 patients. The TIL-B frequencies were correlated with patient survival, gene-expression profiling (GEP) data GSE31312, and frequencies of DLBCL-infiltrating immune cells quantified by fluorescent multiplex immunohistochemistry (mIHC). To validate the prognostic significance of TIL-B frequencies, we assembled a validation cohort of 94 DLBCL patients treated at Duke University Medical Center. TIL-Bs in tissues were quantified by flow cytometry immunophenotyping. Ratios of TIL-Bs to abnormal B cells were assessed for prognostic effects. Results: First, we found thathigh frequencies of TIL-Bs and clonotypic diversity were associated with significantly favorable prognostic effects in 138 DLBCL patients with their malignant B-cell IGH-VDJ clonotypes identified (Figure A). The prognostic effects of TIL-Bs outweighed those of the germinal center B-cell-like/activated B-cell-like classification (Figure B). Second, patients with high frequencies of TIL-Bs compared with those without had significant upregulation of immune response genes by GEP (Figure C), higher CD4 T cell infiltration quantified by fluorescent mIHC (Figure D), and enrichment of EcoTyper-defined specific cell states, including significantly increased frequencies of B cell state S2 (pre-memory), CD4 T cell state S3 (naïve), follicular helper T cell state S3, and endothelial cell state S3, whereas lower frequencies of B cell state S5 (plasmablast) and follicular helper T cell state S1. Third, high TIL-B abundance in 79 ‘DJ-only’ clonotype cases and additional 52 cases assessed by light chain clonotype analysis showed similar favorable prognostic effects and associations with upregulated immune gene expression and CD4 T cell infiltration. Fourth, the identified GEP signatures, prominent with genes involved in T-dependent B cell activation and T cell activation and differentiation, showed significant prognostic effects in two GEO datasets. Fifth, TIL-B abundance showed significant prognostic effects in DLBCL cases infiltrated with T-cells in both the discovery study (Figure E) and validation study (Figure F, flow cytometry cohort). Conclusions: TIL-B frequencies and clonotypic diversity have remarkable prognostic and biological effects in DLBCL, which has significant implications for developing novel therapeutic strategies. Our study identified a new prognostic biomarker in DLBCL and an important player in anti-lymphoma immune responses, providing a new point of view to analyze the tumor biology in aggressive B-cell lymphoma and precisely identify prognostic determinants.

Mitigating the Risk of Cytokine Release Syndrome (CRS): Preliminary Results from a DLBCL Cohort of Epcore NHL-1

Background: Epcoritamab SC, a CD3xCD20 T-cell-engaging bispecific antibody, has recently been approved by the US FDA for the treatment of adults with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), not otherwise specified, including DLBCL arising from indolent lymphoma, and high-grade B-cell lymphoma after ≥2 lines of systemic therapy. As a single agent, epcoritamab SC has demonstrated deep, durable responses with a manageable safety profile in patients with R/R large B-cell lymphoma in the expansion portion of the phase 1/2 EPCORE ™ NHL-1 trial (NCT03625037). Cytokine release syndrome (CRS) events in the dose expansion part of the trial were primarily low grade (49.7% overall; 31.8% grade [G] 1, 15.3% G2, 2.5% G3); timing was predictable, and the majority of events occurred following the first full dose at cycle 1 day 15 (C1D15). To mitigate CRS in dose expansion, subcutaneous administration, step-up dosing, and premedication, including prednisolone, were used. Here, we present preliminary results from a DLBCL optimization cohort of the EPCORE NHL-1 trial that further investigates mitigating the risk of CRS in patients treated with epcoritamab SC monotherapy. Methods: Adult patients with R/R CD20 + DLBCL (previously treated with ≥2 lines of systemic therapy) were enrolled to receive epcoritamab SC in 28-d cycles as follows: weekly, C1-3; every 2 weeks, C4-9; every 4 weeks, C≥10 until progressive disease or unacceptable toxicity. Patients received 2 step-up doses (step-up dose 1, 0.16 mg, and step-up dose 2, 0.8 mg) followed by 48-mg full doses. To further mitigate CRS, C1 of the optimization cohort included mandatory administration of dexamethasone 15 mg as premedication on D1, D8, D15, and D22 and as prophylaxis on D2-4, D9-11, D16-18, and D23-25, and diphenhydramine and acetaminophen as premedication on D1, D8, D15, and D22 with each dose. In C1, it was strongly recommended that patients be well hydrated and that antihypertensive medications be held for 24 h prior to epcoritamab SC administration. Patients were also encouraged to monitor their temperatures following the first 4 doses. Hospitalization and inpatient observation were optional. The primary endpoint was rate of G2 or higher CRS and all CRS events. Secondary pharmacokinetic/pharmacodynamic (PK/PD) analyses were performed. Results: As of April 21, 2023, 24 patients (median age, 65 y) had been treated in this DLBCL optimization cohort. The median number of prior lines of treatment was 3 (range, 2-10), 75% of patients were primary refractory, 71% had stage IV disease, and 58% had prior CAR T. With a median follow-up of 1.3 mo, 18 patients (75%) remained on treatment. The most common treatment-emergent AEs (TEAEs) of any grade were infections (38%; COVID-19, 8%), fatigue (21%), CRS (17%), headache (17%), anemia (13%), constipation (13%), decreased platelet count (13%), dyspnea (13%), hyponatremia (13%), insomnia (13%), and neutropenia (13%; febrile neutropenia, 4%). All CRS events were G1; 1 patient was treated with anticytokine therapy (tocilizumab); there were no treatment discontinuations due to CRS. The most commonly observed CRS symptom was fever (100%). Most CRS events (3/5 events) occurred following the first full dose on C1D15. The median time to CRS resolution was 3.5 d (range, 1-25) and all events resolved. Compared with the DLBCL expansion cohort, circulating interleukin 6 (IL-6) levels were decreased 24 h after the first full dose (C1D15) of epcoritamab SC ( Figure). The median circulating IL-6 level at C1D16 was lower in the dose optimization cohort at 6.92 pg/mL (2.97 pg/mL at C1D1 predose), compared with 21.24 pg/mL (2.45 pg/mL at C1D1 predose) in the DLBCL expansion cohort. The addition of dexamethasone and fluids in optimization did not appear to interfere with T-cell margination or T-cell activation, given that the fold-change values of T-cell absolute counts and percentage of activated T cells were similar between DLBCL optimization and expansion cohorts at C1D16. No patients experienced ICANS, clinical tumor lysis syndrome, or fatal TEAEs. Conclusions: Encouraging preliminary data from this DLBCL CRS optimization cohort, which incorporates prophylactic dexamethasone and hydration of patients during cycle 1, indicate that this approach is effective in decreasing rates and severity of CRS. Data with additional patients and follow-up will be presented.

Disturbed Plasma Lipidomic Profiles in Females with Diffuse Large B-Cell Lymphoma: A Pilot Study.

Lipidome dysregulation is a hallmark of cancer and inflammation. The global plasma lipidome and sub-lipidome of inflammatory pathways have not been reported in diffuse large B-cell lymphoma (DLBCL). In a pilot study of plasma lipid variation in female DLBCL patients and BMI-matched disease-free controls, we performed targeted lipidomics using LC-MRM to quantify lipid mediators of inflammation and immunity, and those known or hypothesised to be involved in cancer progression: sphingolipids, resolvin D1, arachidonic acid (AA)-derived oxylipins, such as hydroxyeicosatetraenoic acids (HETEs) and dihydroxyeicosatrienoic acids, along with their membrane structural precursors. We report on the role of the eicosanoids in the separation of DLBCL from controls, along with lysophosphatidylinositol LPI 20:4, implying notable changes in lipid metabolic and/or signalling pathways, particularly pertaining to AA lipoxygenase pathway and glycerophospholipid remodelling in the cell membrane. We suggest here the set of S1P, SM 36:1, SM 34:1 and PI 34:1 as DLBCL lipid signatures which could serve as a basis for the prospective validation in larger DLBCL cohorts. Additionally, untargeted lipidomics indicates a substantial change in the overall lipid metabolism in DLBCL. The plasma lipid profiling of DLBCL patients helps to better understand the specific lipid dysregulations and pathways in this cancer.

EXPLORING DIFFERENTIAL MUTATIONAL DISTRIBUTION BY TARGETED SEQUENCING IN A R‐CHOP TREATED COHORT OF DIFFUSE LARGE B‐CELL LYMPHOMA PATIENTS

Background: Diffuse large B-cell lymphoma (DLBCL) harbors striking clinical and molecular heterogeneity, which continues to encumber risk stratification with a consequently high rate of refractory/relapsed patients (pts). Though the genomic landscape of DLBCL has been comprehensively uncovered, the search for eligible molecular biomarkers continues. Exploratively, we set out to retrospectively evaluate differential mutational distributions in a DLBCL cohort using targeted sequencing. Patients and method: A cohort of 105 de novo DLBCL pts, uniformly treated with first-line R-CHOP, were studied. Thirty pts relapsed, of which 70% had early relapses (<2 years after completing therapy), while 30% had late relapses (≥2 years). Targeted next-generation sequencing (90 gene panel) was applied on archival paraffin-embedded diagnostic samples and, if available, first relapse samples. Results: In total, 118 samples were sequenced, each displaying a median of 12 (range 1–46) putative somatic protein-coding mutations. Germinal center B-cell (GCB) DLBCL (n = 60) displayed a differential somatic signature with enrichment of EZH2, TNFRSF14, BCL2, ACTB, SOCS1, and FAS mutations (Fisher's Exact, p < 10-4), whereas mutations in CDKN2A, PRDM1, MYD88, and CD79B were significantly enriched in non-GCB pts (p < 10-4, n = 44). Survival analysis confirmed inferior overall survival (OS) in non-GCB DLBCL (5-year OS, log-rank (Mantel-Cox), p = 0.01, hazard ratio (HR) 1.7). Pts with double-hit biology (DHB), defined as either MYC and BCL2 and/or BCL6 fluorescent in situ hybridized positive and/or with MYC and BCL2 immunohistochemical double expression (n = 32), did not display a significant mutational signature or differential OS. However, a subgroup of DHB pts characterized by mutations in MYC, PRDM1, or IRF4 (n = 15) had markedly inferior OS (5-year OS, log-rank, p = 0.0003, HR 3.34) compared to negative non-DHB pts (n = 55) or negative non-DHB/DHB pts (p = 0.0017, HR 2.7, n = 72). Noticeably, ACTB mutations were only present in non-DHB pts. The mutational distribution at diagnosis did not differ between pts with relapse and in sustained remission. However, in the relapse group, GNA13 mutation at diagnosis was more frequent in early relapses than late relapses (43% vs. 0%, Fisher’s Exact without correction, p = 0.03). The presence of GNA13 in the entire cohort showed a trend towards inferior survival. Conclusion: Differential distribution with significant mutational signatures were expectedly found in GCB versus non-GCB, but not in subgroups with DHB or relapse. Interestingly, mutations in MYC, PRDM1 or IRF4 identified a distinct subset of DHB pts with inferior survival. Furthermore, GNA13 mutations were significantly enriched in early relapse pts. These preliminary findings call for validation of GNA13 as a potential marker of early relapse as well as the prognostic value of MYC, PRDM1 and IRF4 mutations in DHB DLBCL. The research was funded by: The Danish Cancer Society and The Vissing Foundation Keywords: aggressive B-cell non-Hodgkin lymphoma, genomics, epigenomics, and other -omics, tumor biology and heterogeneity Conflicts of interests pertinent to the abstract T. S. Larsen Consultant or advisory role Roche, Gilead, Novartis, Celgene/BMS Research funding: Genentech

Biological and clinical relevance of CD79 protein and gene expression in diffuse large B‐cell lymphoma

Introduction: CD79B is a target of polatuzumab vedotin, an antibody–drug conjugate, which may improve the prognosis of both previously untreated and relapsed/refractory patients with diffuse large B-cell lymphoma (DLBCL). However, the biological and clinical significance of CD79B protein and gene expression in DLBCL is largely unknown. Methods: We retrospectively analyzed de novo DLBCL patients, who were diagnosed and received rituximab-based immunochemotherapy from 2008 through 2018 in the Okayama Hematology Study Group from Japan. Immunohistochemistry (IHC) staining was performed using a CD79B antibody (AT107-2), and protein expression was assessed based on H-score according to a previous study (Sehn L et al. JCO 2020). We also performed gene expression profile-based cell-of-origin (COO) classification, including double-hit signature (DHITsig) which has been renamed to dark zone signature (DZsig) (Waleed A et al. Blood 2022), using the NanoString DLBCL90 assay. Results: CD79B IHC expression was evaluable in 602 cases. We idefined two groups according to median H-score of CD79B expression: CD79Bhigh and CD79Blow. The COO subtypes were assigned as follows: 308 patients (51%) with activated B-cell-like (ABC)-DLBCL, 196 (33%) with germinal center B-cell-like (GCB)-DLBCL, 32 (5%) with DZsig-pos DLBCL and 66 (11%) with unclassified (UNC). H-score of CD79B was the lowest in patients with ABC-DLBCL followed by GCB-DLBCL and DZsig-pos DLBCL in ascending order (Kruskal–Wallis test P < .00001; Figure A). Indeed, CD79Blow tumors were significantly enriched in ABC-DLBCL (57%) compared to GCB-DLBCL (40%) and DZsig-pos DLBCL (22%), respectively (both, P < .001). Consistently, using publicly available DLBCL datasets (Schmitz et al. NEJM 2018 and Ennishi et al. JCO 2019), we revealed that CD79B gene expression was the lowest in ABC-DLBCL compared to GCB- and DHITsig-DLBCL (Kruskal–Wallis test P = .01; Figure B and C). The association of CD79B expression with COO prompted us to evaluate CD79B expression in normal germinal center B cells. Notably single-cell transcriptomic analyses of six reactive lymphoid tissues from publicly available datasets revealed that the lowest expression of CD79B was found in plasmablasts followed by light zone B cells and dark zone B cells in ascending order (Kruskal–Wallis test P < .0001), supporting the differential expression of CD79Baccording to COO subtype. CD79Blow group had significantly shorter overall survival (OS) in the total DLBCL cohort (log-rank, P < .001) and within ABC-DLBCL (P = .001, Figure D and E). Moreover, CD79B protein expression was significantly associated with OS after adjusting for International Prognostic Index in the total cohort (Cox regression model; P< .001). Keywords: Aggressive B-cell non-Hodgkin lymphoma, Diagnostic and Prognostic Biomarkers Conflicts of interests pertinent to the abstract. K. Sunami Honoraria: Celgene, Sanofi, BMS, Ono, Janssen Research funding: Takeda, AbbVie, GSK, Chugai, Otsuka, MSD, Novartis, Astellas Amgen, Pfizer, Parexel, Kyowa Kirin, Symbio, Agios Y. Hiramatsu Honoraria: Chugai Pharmaceutical Co, Nippon Shinyaku Co, Bristol Myers Squibb, Sanofi K.K. I. Yoshida Honoraria: Kyowa Kirin, Chugai, Eisai, Jannsen, Nippon-shinyaku, Otsuka, Symbio, Takeda, Sumitomo Pharma, Meiji Research funding: Kyowa Kirin, Chugai Y. Maeda Research funding: Chugai, Nippon-shinyaku Other remuneration: Chugai, Eisai, Otsuka, Kyowa Kirin, Takeda D. W. Scott Consultant or advisory role: Abbvie, AstraZeneca, Janssen, Incyte Honoraria: AstraZeneca Research funding: Janssen, Roche/Genentech D. Ennishi Honoraria: Chugai, Eisai, Kyowa Kirin Research funding: Nipponshinyaku, Chugai

Abstract 5557: Patterns of oncogene co-expression at single cell resolution influence survival in diffuse large B-cell lymphoma

Abstract Background: Cancers often overexpress multiple clinically relevant oncogenes. However, it is not known if multiple oncogenes within a cancer combineuniquely in specific cellular sub-populations to influence clinical outcome.We studied this phenomenon using the prognostically relevantoncogenes MYC, BCL2 and BCL6 in Diffuse Large B-Cell Lymphoma(DLBCL). Methods: Quantitative multispectral imaging simultaneously measured oncogene co-expression at single-cell resolution in reactive lymphoid tissue (n=12)and four independent cohorts (n=409) of DLBCL. Mathematically derived co-expression phenotypes were evaluated in DLBCLs with immunohistochemistry (n=316) and nine DLBCL cohorts with gene expression data (n=3974). Bulk and single-cell RNA sequencing was performed on patient-derived B-cells with induced co-expression of MYC,BCL2 and BCL6. Results: Unlike in non-malignant lymphoid tissue where the co-expression of MYC, BCL2 and BCL6 in a B-cell is limited, DLBCLs show multiple permutations of oncogenic co-expression in malignant B-cells. The percentage of cells with a unique combination MYC+BCL2+BCL6-(M+2+6-) consistently predicts survival in contrast to that of other combinations (including M+2+6+). An estimated percentage of M+2+6-cells can be derived from any quantitative measurement of the component individual oncogenes, and correlates with survival in immunohistochemistry and gene expression datasets. Comparative transcriptomic analysis of DLBCLs and transformed patient-derived B-cells identifies cyclin D2 (CCND2) as a potential BCL6-repressedregulator of proliferation in the M+2+6- population. Conclusions: Unique patterns of oncogene co-expression at single-cell resolution affect clinical outcomes in DLBCL. Similar analyses evaluating oncogenic combinations at the cellular level may impact diagnostics and target discovery in other cancers. Citation Format: Michal M. Hoppe, Patrick Jaynes, Shuangyi Fan, Yanfen Peng, Shruti Sridhar, Phuong Mai Hoang, Xin Liu, Sanjay de Mel, Limei Poon, Esther Chan, Joanne Lee, Choon Kiat Ong, Tiffany Tang, Soon Thye Lim, Chandramouli Nagarajan, Nicholas F. Grigoropoulos, Soo-Yong Tan, Susan Swee-Shan Hue, Sheng-Tsung Chang, Shih-Sung Chuang, Shaoying Li, Joseph D. Khoury, Hyungwon Choi, Pedro Farinha, Anja Mottok, David W. Scott, Carl Harris, Alessia Bottos, Gayatri Kumar, Kasthuri Kannan, Laura J. Gay, Hendrik F. Runge, Ilias Moutsopoulos, Irina Mohorianu, Daniel J. Hodson, Yen-Chee Lin, Wee-Joo Chng, Siok-Bian Ng, Claudio Tripodo, Anand D. Jeyasekharan. Patterns of oncogene co-expression at single cell resolution influence survival in diffuse large B-cell 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 5557.

Abstract 1771: Characterization of RHOA inactivation as a driver of CAR-T therapy resistance in diffuse large B-cell lymphoma

Abstract Background: Front-line chemoimmunotherapy for diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma, is effective, however at least 40% of patients relapse or are refractory (r/r). Of this r/r DLBCL cohort, approximately 10% will be cured with conventional second-line treatments consisting of salvage chemotherapy and autologous stem cell transplant. CD19-directed chimeric antigen receptor T-cell (CAR-19) therapies are promising new second-line options in diffuse large B-cell lymphoma (DLBCL) and show exciting 30-40% durable complete responses in heavily pretreated patients. Recent whole-genome sequencing data published by our lab revealed that deletion of Ras homolog family member A (RHOA) is strongly associated with poor response to CAR-19 therapy in r/r DLBCL patients (p = 0.0013). In newly diagnosed DLBCL, 20% of patients harbor a RHOA deletion and another 5% have loss-of-function mutations. To date, no work has comprehensively identified the role of RHOA in DLBCL or how its inactivation may protect CAR-T resistant tumors. Methods: We created a novel in vivo model of RHOA deficient lymphoma by transplanting Eμ-Myc transgenic hematopoietic stem cells (HSCs) transduced with a shRhoa vector. We also created a syngeneic model of RHOA-deficient lymphoma with MYC-driven BL3750 cells. In vitro flow cytometry and Xcelligence real-time cell analysis experiments were utilized to assess cytotoxicity of CAR-19 against RHOA-deficient lymphoma cell lines. RNAseq analysis was conducted on Rhoa knockdown cell lines to elucidate cell-intrinsic mechanisms of lymphomagenesis. Cell proliferation and migration assays were performed to characterize the phenotype of RHOA-deficient DLBCL cell lines. Results: 18 mice were transplanted (11 shRhoa, 7 shRenilla control) and are being monitored for lymphoma development. In vitro CAR-T experiments demonstrated that while RHOA-deficient cells demonstrate a similar degree of killing initially, a population of RHOA-deficient cells persists and enrich at later time points. RNA-seq analysis of A20 shRhoa murine lymphoma cells uncovered enrichment of gene sets associated will cell-cycle progression and interferon (INF) signaling pathways. Cell proliferation assay and Western blot of RHOA inactivated cell lines revealed increased proliferation in shRhoa cells through the AKT/mTOR pathway compared to controls. Conclusions: RHOA-deficient lymphomas, while not entirely evading CAR-19 cells in vitro, demonstrate resistance mechanisms that allows a small population to persist. RNA-seq analysis reveals upregulated oncogenic and immunoinhibitory pathways, consistent with in vitro cell proliferation and Western blot assays. Further research will challenge in vivo RHOA-deficient tumors with CAR-19 cells and employ scRNA-seq to reveal transcriptomic changes within RHOA-deficient lymphoma responsible for CAR-19 resistance. Citation Format: Austin Newsam, Yitzhar Goretsky, Evan Roberts, Daniel Bilbao, Jonathan Schatz. Characterization of RHOA inactivation as a driver of CAR-T therapy resistance in diffuse large B-cell 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 1771.

A Decision-tree Approach to Stratify DLBCL Risk Based on Stromal and Immune Microenvironment Determinants.

A Decision-tree Approach to Stratify DLBCL Risk Based on Stromal and Immune Microenvironment Determinants.

Outcomes in grade 3B follicular lymphoma: an international study led by the Australasian Lymphoma Alliance.

Grade (G) 3B follicular lymphoma (FL) is a rare FL subtype which exists on a histological continuum between 'lowgrade' (Grade 1, 2 and 3A FL) and diffuse large B-cell lymphoma (DLBCL) appearing to share features with each. Clinical characteristics and outcomes are poorly understood due to lack of adequate representation in prospective trials and large-scale analyses. We analyzed 157 G3BFL cases from 18 international centers, and two comparator groups; G3AFL (n=302) and DLBCL (n=548). Composite histology with DLBCL or low-grade FL occurred in approximately half of the G3BFL cases. With a median of 5 years follow-up, the overall survival and progression-free survival of G3BFL patients was better than that of DLBCL patients (P<0.001 and P<0.001, respectively); however, G3BFL patients were younger (P<0.001) with better performance status (P<0.001), less extranodal disease (P<0.001) and more frequently had normal lactate dehydrogenase (P<0.001) at baseline. The overall and progression-free survival of patients with G3BFL and G3AFL were similar (P=0.83 and P=0.80, respectively). After frontline immunochemotherapy, 24% of G3BFL relapsed; relapse rates were 63% in the DLBCL cohort and 19% in the low-grade FL cohort. Eight percent of relapses occurred beyond 5 years. In this G3BFL cohort, the revised International Prognostic Index successfully delineated risk groups, but the Follicular Lymphoma International Prognostic Index did not. We conclude that patients with immunochemotherapy-treated G3BFL have similar survival outcomes to those with G3AFL, yet a favorable baseline profile and distinctly superior prognosis compared to patients with DLBCL.

A prognostic 15-gene model based on differentially expressed genes among metabolic subtypes in diffuse large B-cell lymphoma.

The outcomes of patients with diffuse large B-cell lymphoma (DLBCL) vary widely, and about 40% of them could not be cured by the standard first-line treatment, R-CHOP, which could be due to the high heterogeneity of DLBCL. Here, we aim to construct a prognostic model based on the genetic signature of metabolic heterogeneity of DLBCL to explore therapeutic strategies for DLBCL patients. Clinical and transcriptomic data of one training and four validation cohorts of DLBCL were obtained from the GEO database. Metabolic subtypes were identified by PAM clustering of 1,916 metabolic genes in the 7 major metabolic pathways in the training cohort. DEGs among the metabolic clusters were then analyzed. In total, 108 prognosis-related DEGs were identified. Through univariable Cox and LASSO regression analyses, 15 DEGs were used to construct a risk score model. The overall survival (OS) and progression-free survival (PFS) of patients with high risk were significantly worse than those with low risk (OS: HR 2.86, 95%CI 2.04-4.01, p < 0.001; PFS: HR 2.42, 95% CI 1.77-3.31, p < 0.001). This model was also associated with OS in the four independent validation datasets (GSE10846: HR 1.65, p = 0.002; GSE53786: HR 2.05, p = 0.02; GSE87371: HR 1.85, p = 0.027; GSE23051: HR 6.16, p = 0.007) and PFS in the two validation datasets (GSE87371: HR 1.67, p = 0.033; GSE23051: HR 2.74, p = 0.049). Multivariable Cox analysis showed that in all datasets, the risk model could predict OS independent of clinical prognosis factors (p < 0.05). Compared with the high-risk group, patients in the low-risk group predictively respond to R-CHOP (p = 0.0042), PI3K inhibitor (p < 0.05), and proteasome inhibitor (p < 0.05). Therefore, in this study, we developed a signature model of 15 DEGs among 3 metabolic subtypes, which could predict survival and drug sensitivity in DLBCL patients.