Hampel, Paul J.

Introduction Venetoclax + rituximab resulted in a 2-year progression-free survival estimate of 85% in the mostly 2nd-line, post-chemotherapy setting of the MURANO clinical trial (Seymour NEJM 2018). Short remissions with venetoclax in patients (pts) with prior cBTKi treatment (tx) for CLL are reported. However, these cohorts have included heavily pre-treated pts. Here, we report outcomes with venetoclax-based regimens in a contemporary cohort with cBTKi-exposed CLL and no prior chemotherapy. Methods We conducted a retrospective study of pts who received venetoclax for relapsed CLL after prior cBTKi tx at Mayo Clinic and across 8 centers in France. Pts with any prior chemotherapy tx were excluded. Pts were grouped as cBTKi-resistant (CLL disease progression on cBTKi) and cBTKi-exposed (any prior cBTKi tx but without disease progression). Overall survival (OS) was analyzed as the time from initiation of venetoclax until date of death or last known to be alive. Time to next therapy or death (TTNTD) after venetoclax was defined as the time from venetoclax initiation until the earliest date of next tx or death. Cox proportional hazards regression models were used to estimate associations of factors with OS and TTNTD. Results A total of 85 pts received venetoclax, including: venetoclax monotherapy (n=13, 15%), venetoclax + rituximab (n=45, 53%), and venetoclax + obinutuzumab (n=27, 32%). Patient characteristics at the time of venetoclax start were as follows: median age 69 years (interquartile range [IQR] 62-77), 59 (69%) male, 45% (33/73 evaluated) with TP53 disruption (del(17p) or TP53 mutation), 82% (46/56 evaluated) with unmutated IGHV, and 41% (15/37 evaluated) with complex karyotype (CK; ≥3 clonal structural or numerical abnormalities on karyotype). The median prior lines of therapy was 1 (IQR 1, 2); 32 (38%) pts had received prior anti-CD20 monoclonal antibody and 8 (9%) pts had received 2 prior cBTKi. Prior cBTKi tx was stopped for a reason other than disease progression in 46 (54%) pts (cBTKi-exposed) and due to CLL progression in 39 (46%) pts (cBTKi-resistant). TP53 disruption, unmutated IGHV, and CK were more common in the cBTKi-resistant subgroup. Among pts with cBTKi-resistant CLL, 60% (12/20 evaluated) had a BTK and/or PLCG2 mutation. Median follow-up from start of venetoclax-based therapy was 20 months. The median TTNTD and OS for the entire cohort was 36 (95% CI 29-not evaluable [NE]) and 68 (95% CI 39-NE) months, respectively. Among the 46 pts with cBTKi-exposed CLL, the median duration of prior cBTKi tx was 6.7 months (IQR 1.8, 23.7). The median TTNTD and OS from venetoclax start were both 78 months in pts with cBTKi-exposed CLL. The 24-month TTNTD and OS estimates were 73% and 81%, respectively. Among the 39 pts with cBTKi-resistant CLL, the median duration of prior cBTKi tx was 42.3 months (IQR 23.4, 60.1). The median TTNTD from venetoclax start in pts with cBTKi-resistant CLL was 30 months. The 24-month TTNTD estimate was 65% in the cBTKi-resistant subgroup, 53% with venetoclax monotherapy (n=5), 62% with venetoclax + rituximab (n=30), and 100% venetoclax + obinutuzumab (n=4). The median OS from venetoclax initiation was 39 months overall in pts with cBTKi-resistant CLL. The 24-month OS estimate was 84% in the cBTKi-resistant subgroup overall, 53% with venetoclax monotherapy, 87% with venetoclax + rituximab, and 100% with venetoclax + obinutuzumab. On a univariate analysis in the whole cohort, only TP53 disruption was associated with shorter TTNTD (HR 2.23; 95% CI 1.02-4.87; P=0.04) and only older age was associated with shorter OS (HR 1.05; 95% CI 1.007-1.095, P=0.02). On a univariate analysis in the cBTKi-resistant subgroup, only TP53 disruption was associated with shorter TTNTD (HR 6.68; 95% CI 1.51-29.46; P=0.01) and OS (HR 7.95; 95% CI 1.02-61.97; P=0.04). Duration of prior cBTKi exposure (as a continuous variable) was not associated with survival outcomes in the cBTKi-resistant subgroup. Conclusions Pts with chemotherapy-naïve, cBTKi-treated CLL had worse than expected outcomes with venetoclax-based tx in a mostly 2nd-line tx cohort, particularly pts with cBTKi-resistant CLL. The frequency of high-risk disease features, shorter duration of disease control with their initial cBTKi tx, and small cohort size warrant caution in generalizing these results to all pts with cBTKi-resistant disease. Novel tx trial strategies in 1st- and 2nd-line settings remain a high priority for high-risk pts.

Background: Despite effective front-line therapies, DLBCL & MM have high relapse rates. Novel therapies like CAR-T & bispecific antibodies (BsAb) offer deep & durable remission compared to salvage therapies, but have a unique toxicity profile (TP) that requires monitoring. With no head-to-head trials, the rationale for therapy selection may vary. This study explores provider choices, sequencing preferences, & access barriers. Methods: Two anonymous surveys (MM and DLBCL) of US-based Hematologists were conducted from 2/2024 to 6/2024, on practice settings, CAR-T & BsAb availability, treatment preferences & barriers. Responses were analyzed to assess preferences across clinical scenarios. Results: Surveys were completed by 37 MM & 45 DLBCL providers. Most were at centers offering both CAR-T & BsAb. Most gave CAR-T inpatient, & BsAb outpatient. CAR-T was given by 73% MM providers & 66% DLBCL (92% used Cilta-cel, 96% used Ide-cel; 100% used Axi-cel, 90% used Liso-cel & 73% Tisa-cel). In MM, 78% used Teclistamab, 60% Talquetamab & 24% Elranatamab. In DLBCL, 62% used Epcoritamab & 40% Glofitamab. Providers preferred CAR-T over BsAb in MM after 4+ prior lines of therapy (LOT) (89%), & in DLBCL after 2+ prior LOT (93%). CAR-T was favored more among academic providers & those at CAR-T centers. Practice volume did not impact selection. Among providers at centers with BsAb-only, CAR-T was preferred by 60% (MM) and 50% (DLBCL). Providers at centers without both favored CAR-T (MM: 75%, DLBCL: 86%). CAR-T was chosen for better outcomes, short treatment, center choice, & prior experience. Other factors that influenced decisions were lower incidence of cytopenia/infection & “BsAb effective post-CAR-T, less so vice versa” (MM), & “curative potential of CAR-T” (DLBCL). Logistical barriers & institutional constraints influenced BsAb selection: CAR-T unavailability, access to specialized centers, referral complexity, insurance delay, manufacturing delay & hospitalization needs. In MM, 78% providers preferred Cilta-cel over Ide-cel, especially academic providers & those with CAR-T experience. CAR-T volume did not impact selection. Cilta-cel was preferred due to perceived better response rate (RR), more experience, “progression-free survival (PFS) benefit”, center choice, & logistical issues with Ide-cel. Ide-cel was selected due to center choice, favorable TP & insurance preference. Teclistamab was preferred by 78% due to more experience, better RR, TP & center choice, Elranatamab by 11% (better TP, RR, & “PFS”), & Talquetamab by 11% due to having a non-BCMA target. Academic providers preferred Teclistamab (89% vs 50%), & nonacademic providers preferred Talquetamab (38% vs 4%) and Elranatamab (13% vs 8%). In DLBCL after 2+ LOT, 69% favored Axi-cel due to prior experience, RR, center choice, & logistical issues with other products. Liso-cel & Tisa-cel were chosen by 27% & 2%, respectively, due to favorable TP. Axi-cel was also preferred 2nd line by 73% for similar reasons, while 24% favored Liso-cel for its favorable TP. Epcoritamab was preferred by 56% (subcutaneous injection, more experience & center choice) & Glofitamab by 42% (shorter treatment duration, easy administration, more experience, & center choice). Practice setting & volume did not impact selection between products in DLBCL. InBCMA-naïve MM pts, majority (97%) chose an anti-BCMA agent over GPRC5D due to better RR, TP, prior experience, & center choice. InBCMA-exposed pts, most (92%) favored an anti-GPRC5D agent. In contrast in DLBCL, 80% chose CD19 CAR-T after prior CD19-directed therapy, & 18% chose CD20 BsAb. Therefore, antigen escape was less of a concern in DLBCL vs MM. For relapse after 2nd line CAR-T in DLBCL, 78% preferred BsAb over other salvage options due to better RR, TP, & more experience. Providers prioritized RR, survival, & TP in decision making. Treatment logistics, duration, frequency, & cost were less crucial. MM providers also prioritized quality of life, which was less so in DLBCL. There were no differences in priority based on practice setting & experience with CAR-T. Conclusion: The study highlights factors influencing therapy choices in MM & DLBCL. Despite CAR-T's potential for better outcomes, significant access barriers exist. Efforts to streamline referral pathways, logistics, & expanding availability are crucial to improve outcomes. Understanding these preferences & barriers can guide future management strategies.

Background: Chemoimmunotherapy using rituximab, cyclophosphamide, doxorubicin hydrochloride (hydroxydaunomycin), vincristine sulfate (Oncovin), and prednisone (R-CHOP) has been the standard of care treatment of DLBCL for over 20 years. Despite its widespread usage, there is no accepted standard for the dose of prednisone in this setting which varies from fixed-dose (100 mg daily for 5 days) to different levels of BSA-adjusted dosage (ranging from 40-100 mg/m2 daily for 5 days). BSA-adjusted dosage results in high doses of prednisone administered to patients with increased body surface area which may lead to significant adverse events. We performed a systematic review and meta-analysis to determine if fixed-dose prednisone during R-CHOP therapy results in equivalent outcomes compared to BSA-adjusted dosing. Methods: A comprehensive search of several databases from each database's inception to April 29th, 2024, English language, was conducted. The databases included Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus. The search strategy was designed and conducted by an experienced librarian with input from the study's principal investigator. Controlled vocabulary supplemented with keywords was used to search for prospective clinical studies of R-CHOP for adult patients with untreated DLBCL. Search results were reviewed independently by 2 members of the study team for final inclusion. Discrepancies were adjudicated by a third member and reviewed by the senior author. Prednisone dosage and clinical outcomes were abstracted from the available public data. Meta-analysis was performed using the metafor package in R version 4.2.2 by applying a mixed-effects model to combine results from the multiple studies. The analysis was first conducted overall to determine the general effect, and then stratified by prednisone dose (fixed- vs. BSA-adjusted) to explore dose-dependent variations in outcomes. Results: Our search resulted in 2287 entries which were individually reviewed by the study team. A total of 30 studies with a combined sample size of 3573 treated patients fulfilled the inclusion criteria and were included in the final analysis set. Nineteen (63%) studies with a combined sample size of 1930 patients (median 155, range 12-399) used fixed-dose prednisone. Eleven (37%) studies with a combined sample size of 1643 patients (median 70, range 9-439) used BSA-adjusted dosing. Overall survival (OS) at 2 years data were available for 11 (37%) of the studies. Progression free survival (PFS) at 2 years data were available for 8 studies (27%). Overall response rate (ORR) and complete response rate (CRR) data were available for 16 (54%) and 14 (47%) of the included studies, respectively. OS at 2 years for all studies was 84% (SD 78%-91%) and did not differ between fixed-dose (88%, SD 79%-97%) and BSA-adjusted dose (82%, 73%-91%). PFS at 2 years for all studies was 77% (SD 68%-85%) and did not differ between fixed-dose (80%, SD 68%-93%) and BSA-adjusted dose (74%, SD 62%-86%). ORR for all studies was 86% (SD 79%-92%) and did not differ between fixed-dose (86%, SD 76%-96%) and BSA-adjusted dosage (84%, SD 80%-88%). CRR for all studies was 70% (SD 61%-80%) and did not differ between fixed-dose (67%, SD 54%-81%) and BSA-adjusted dose (77%, SD 64%-89%). Heterogeneity tests performed according to available clinical outcomes yielded results between 0% and 76%. Conclusion: The result of our systematic review and meta-analysis combining 30 prospective studies and a total of 3573 patients with newly diagnosed DLBCL treated with frontline R-CHOP found no difference in clinical outcomes between patients treated with fixed-dose and BSA-adjusted dose prednisone. Our findings provide scientific evidence for the widespread practice of capping prednisone at the maximum dose of 100 mg daily for 5 days, potentially avoiding unnecessary adverse effects from BSA-adjusted dosing.

Abstract Background Hypomagnesemia has been correlated with inferior outcomes in patients with large B cell lymphoma (LBCL) undergoing stem cell transplants. As T-cell and myeloid cell dysfunction have been associated with low magnesium conditions, we investigated whether serum magnesium (Mg) levels could predict clinical outcomes in LBCL patients who received chimeric antigen receptor T-cell therapy. Methods Patients with LBCL who received axi-cel under the ZUMA-1 trial or as FDA approved therapy at Mayo Clinic were examined. Serum samples were obtained at specified time points and cytokine analysis was performed. Single cell RNA sequencing was performed on peripheral blood mononuclear cells. The Student T-test, Kruskal Wallis, or Fisher's Exact Tests were used to compare differences in demographics across Mg levels. Survival curves were plotted using the Kaplan-Meier methodology and compared using the Wilcoxon test. Results We found that hypomagnesemia before lymphodepletion chemotherapy predicted for inferior progression-free and overall survival in the pivotal study ZUMA-1 (NCT02348216). These results were validated in an independent cohort of LBCL patients receiving axicabtagene ciloleucel (axi-cel) at Mayo Clinic. Hypomagnesemia correlated with increased inflammatory serum markers and cytokine levels including ferritin, IL-6, IL1Ra, IL-8, and MIP1a. scRNAseq analysis unveiled altered immune interactions between monocytes and T cells with a concordant immune suppressive transcriptome. Conclusions Hypomagnesemia at the time of CAR-T infusion associates with an unfavorable inflammatory profile and decreased response and survival in LBCL patients receiving axi-cel. These findings suggest a potentially actionable prognostic factor for patients with large cell lymphoma undergoing CAR-T.

AbstractBackgroundChronic lymphocytic leukemia (CLL) is a heterogeneous disease. Whereas some patients have an indolent disease, others experience an aggressive course and early death. Our aim was to investigate if modifiable and non‐modifiable medical history and lifestyle factors prior to diagnosis had an impact on the natural course of the disease.MethodIn 1154 CLL patients, we assessed if the weight, physical activity, smoking, and alcohol consumption or non‐modifiable characteristics including family history of lymphoid malignancy and medical history were associated with time‐to‐first‐treatment (TTFT) and adjusted all results for the CLL‐International Prognostic Index (CLL‐IPI).ResultsTTFT was shorter for patients with high/very high‐risk CLL‐IPI than those with low/intermediate risk CLL‐IPI. In the adjusted analysis we did not find additional impact on TTFT besides CLL‐IPI from any environmental characteristics assessed.ConclusionsWe found limited impact of environmental factors on the natural course of CLL (measured as the TTFT in treatment naïve patients) providing valuable knowledge, and potential relief, to share with patients at the time of diagnosis.

7011 Background: Monoclonal B-cell lymphocytosis (MBL) is a precursor to chronic lymphocytic leukemia (CLL) but also a risk factor for other lymphoid malignancies. Clonal hematopoiesis (CH), originally defined as the presence of mutations in myeloid driver genes, is a precursor to myeloid malignancies. Recently, CH that includes genes associated with lymphoid malignancies has been reportedly associated with risk of lymphoid malignancies, and particularly CLL. Little is known about the association between CH and MBL and their joint effects on risk of hematological malignancies (HM). Methods: Study participants were from the Mayo Clinic Biobank, a large-scale biorepository of patients who provided a peripheral blood sample. CH at enrollment was determined using whole-exome sequencing (50x coverage). Myeloid-CH (M-CH) was based on mutations located in 56 genes associated with myeloid malignancies. Lymphoid-CH (L-CH) was based on 235 genes associated with lymphoid malignancies. Individuals were screened for MBL using eight-color flow cytometry in two different cohorts of Biobank participants. Cohort 1 (N=3883) included participants who had available sample for MBL screening at enrollment. Cohort 2 (N=5684) were participants recontacted to provide a sample for MBL screening. Incident HM were identified using ICD codes and confirmed via medical record review. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Cox regression was used to estimate hazard ratios (HR), with time defined as date between MBL sample and the first of incident HM, death, or 9/30/2023. Analyses were adjusted for age at MBL screening and sex. Results: In total, 9567 individuals (39% male, median age 66 years) were screened for MBL with available CH, of whom 17% were positive for MBL, 7% were positive for M-CH, and 2% were positive for L-CH. We found no evidence of an association between M-CH and MBL (OR=1.11, 95% CI:0.91-1.34) nor L-CH and MBL (OR=1.05, 95% CI:0.70-1.55). When subset to Cohort 1, where the same sample was used for both CH and MBL screening, the results held (M-CH OR=1.11, 95% CI: 0.83-1.48; L-CH OR=0.82, 95% CI:0.40-1.53). Next, we investigated the effect of each of these precursors with incident HM. Median follow-up was 4 years, and 78 individuals developed incident HM (31 myeloid, 49 lymphoid overall, 8 CLL). When modeling both precursors, both L-CH (HR=6.23, 95% CI:2.46-15.79) and MBL (HR=3.89, 95% CI:2.17-6.99) were independently associated with incident lymphoid malignancy. When excluding CLL events, the association held (L-CH: HR=5.94, 95% CI:2.11-16.77; MBL: HR=2.95, 95% CI:1.54-5.66). Only M-CH was significantly associated with incident myeloid malignancies. Conclusions: In the largest cohort with MBL and CH precursors measured, we found no evidence of an association between them. However, both MBL and L-CH were strong independent risk factors for incident lymphoid malignancies.

7050 Background: The management of Richter transformation (RT) of CLL represents an unmet clinical need. We previously reported modest efficacy of pembrolizumab monotherapy in an initial cohort of patients with RT (Ding, et al, Blood 2017). Here we report updated results of this trial, including an expansion cohort and a combination therapy cohort. Methods: Patients with biopsy proven RT to diffuse large B-cell lymphoma were enrolled and treated with single agent pembrolizumab (200 mg IV Q3W). Patients with progressive disease (PD) or stable disease (SD) after 3 months of pembrolizumab monotherapy were allowed to add a B-cell receptor (BCR) kinase inhibitor. The primary end point was overall response rate (ORR). Results: A total of 26 patients with RT were enrolled (9 in initial cohort and 17 in expansion cohort). The median age was 68.5 years. Ten (38%) patients had del(17p) or TP53 mutation. The median number of prior lines of therapy was 3 (range 1-10). Fifteen (58%) patients had received ibrutinib previously (14 of whom had PD on ibrutinib). With pembrolizumab monotherapy (n=26), the ORR was 23.1%, with 2 (7.7%) complete response (CR), 4 (15.4%) partial response (PR), and 7 (26.9%) SD. Of the 6 patients with confirmed CR or PR, responses occurred after a median of 2 cycles of monotherapy. The median duration of response (DOR) was 3.2 months (95% CI 2.8-NA). The median progression-free survival (PFS) was 2.6 months (95% CI 1.6-3.6). Sixteen patients went on to receive a BCR kinase inhibitor (ibrutinib [n=15], idelalisib [n=1]) in combination with pembrolizumab, after SD or PD on pembrolizumab monotherapy. The ORR to combination therapy was 62.5%, with 4 (25.0%) CR and 6 (37.5%) PR. Of the 10 patients with confirmed CR or PR to combination therapy, responses occurred after a median of 4 cycles of therapy. The median DOR was 4.5 months (95% CI 1.6-NA). The median PFS was 7.6 months (95% CI 2.3-13.3). After a median follow-up of 50.4 (95% CI 34.0-56.0) months, the median overall survival (OS) for all 26 patients with RT was 11.6 months (95% CI 7.5-20.1), and the 2-year OS rate was 27%. Treatment-related adverse events (TRAEs) of any grade occurred in 24 (92%) patients, including anemia (54%), thrombocytopenia (58%), neutropenia (54%), leukopenia (35%), lymphopenia (23%), dyspnea (23%), diarrhea (19%), and nausea (23%). Treatment-related grade 3 or above AEs occurred in 21 (81%) patients, including neutropenia (38%), leukopenia (31%), thrombocytopenia (27%), anemia (15%), febrile neutropenia (12%), and lung infection (12%). Conclusions: This expanded analysis confirmed that pembrolizumab has modest single agent activity in RT. Combination therapy with pembrolizumab and a BCR kinase inhibitor is associated with increased efficacy (ORR >60%), similar to other reports. These results support further investigation of immune checkpoint inhibitor-based combination therapy in RT. Clinical trial information: NCT02332980 .

e14535 Background: Cytokine release syndrome (CRS) is the most common complication of chimeric antigen receptor T cells (CAR-T) for hematologic malignancies. We hypothesized that patients undergoing CAR-T therapy who are on metformin will experience a lower incidence or severity of CRS than patients not on this medication. Methods: We evaluated all patients treated with CAR-T at Mayo Clinic Rochester between 1/1/2018 and 1/31/2023, and abstracted relevant clinical and laboratory characteristics to determine the incidence and severity of CRS, PFS as well as OS in patients who were, or were not, on metformin before and during CAR-T therapy for Type 2 diabetes mellitus. We used the Chi-Square test, Mann-Whitney test and the Kaplan-Meier method to analyze data. Results: In the 5-year interval under consideration 237 patients received CAR-T, 168 for non-Hodgkin lymphoma (NHL), and 69 for multiple myeloma (MM). 23 patients (15 NHL and 8 MM) were on metformin at the time of CAR-T. 15 patient developed CRS while on metformin and 175 patients not on metformin (p=0.05). Grade 3 or 4 CRS incidence was 4% in both groups (p=0.41). Of the 153 patients with NHL not on metformin, 121 developed any grade of CRS, while 10 of 15 patients on metformin developed CRS (p=0.268). 4 NHL patients developed CRS Grade ≥3 or higher, while 0 of 15 on metformin developed Grade ≥3 CRS (p=0.237). For the MM patients, the incidence of CRS was 49 patients not on metformin and 5 patients on metformin (p<0.001). 3 MM patients developed CRS Grade ≥3 or higher, while 0 of 8 on metformin developed Grade ≥3 CRS (p=0.346). 12 of 15 patients on metformin with NHL achieved CR compared to 92 of 153 patients not on metformin (p=0.1305). 3 of 8 patients with MM on metformin compared to 24 of 61 patients with MM not on metformin achieved CR or better post CAR-T (p=0.92). Tocilizumab was used in 40% of patients on metformin but in 66% of patients not on metformin (p=0.0016). In NHL patients, PFS from CAR-T infusion was not reached (range: 6.3 to NR) for patients on metformin versus 9.9 months (range: 6.3–19.5) in patients not on metformin (p = 0.3332). In the MM patients, progression-free survival (PFS) from CAR-T infusion was 8.4 months (95% CI: 7.9–not reached [NR]) for patients on metformin and 22.6 months (13.7–NR) for those not on metformin (p = 0.07). Median OS for NHL patients on metformin was not reached (9.766–NR) versus 32.6 months (18.6–NR) for patients not on metformin (p = 0.7022). Median OS was 17 months (95% CI: 8.3 to NR) for patients with MM on metformin vs NR (95% CI: 9.4 to NR) for patients not on metformin (p = 0.2559). Conclusions: In this retrospective study, the co-administration of metformin during CAR-T cell therapy for NHL and MM appears to be associated with a numerically reduced incidence of CRS. The effect appears to be particularly marked in patients with multiple myeloma. Metformin therapy did not seem to affect the response to CAR-T therapy in either NHL or MM.

Abstract Patients with chronic lymphocytic leukemia (CLL) who develop Richter transformation (RT) have a poor prognosis when treated with chemoimmunotherapy regimens used for de novo diffuse large B-cell lymphoma. Venetoclax, a BCL2 inhibitor, has single-agent efficacy in patients with RT and is potentially synergistic with chemoimmunotherapy. In this multicenter, retrospective study, we evaluated 62 patients with RT who received venetoclax-based treatment outside of a clinical trial, in combination with a Bruton tyrosine kinase inhibitor (BTKi; n=28), rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP) (n=13), or intensive chemoimmunotherapy other than R-CHOP (n=21). The best overall and complete response rates were 36%/25%, 54%/46%, and 52%/38%, respectively. The median progression-free and overall survival estimates for the same treatment groups were 4.9/14.3 months, 14.9 months/not reached, and 3.3/9 months, respectively. CLL with del(17p) was associated with a lower complete response rate in the total cohort (odds ratio [OR] 0.15; 95% confidence interval [CI] 0.04-0.6; p=0.01) and venetoclax-naïve subgroup (OR 0.13; 95%CI 0.02-0.66; p=0.01). TP53 mutated CLL was associated with a lower complete response rate (OR 0.15; 95%CI 0.03-0.74; p=0.02) and shorter progression-free survival (hazard ratio 3.1; 95%CI 1.21-7.95; p=0.02) only in venetoclax-naïve subgroup. No other clinical or baseline characteristics, including prior venetoclax treatment for CLL, showed statistically significant association with outcomes. Grade 3-4 neutropenia and thrombocytopenia events were most frequent with intensive chemoimmunotherapy + venetoclax; grade 3-4 infection rates were similar across treatment groups. In this difficult-to-treat RT patient population, venetoclax-based combination regimens achieved high response rates, with durable remission and survival observed in a subset of patients.

Abstract Background Although CAR T-cell therapy has achieved remarkable response in patients (pts) with B-cell non-Hodgkin’s lymphoma (NHL), 20-30% of pts still have primary refractory disease (PD1), and another 30-40% relapse (PD2). We and others have shown that monocytes can modulate T-cell functions and impact clinical response to chemoimmunotherapy in NHL. Given that monocytes nadir and recovery kinetics differ from lymphocytes post lymphodepletion chemotherapy, we hypothesize that monocyte phenotype at peak CAR-T expansion and in the early month post CAR-T can modulate immune responses. Methods scRNAseq were performed on peripheral blood mononuclear cells of NHL pts prior to lymphodepletion chemotherapy (pre), at peak CAR-T expansion (peak), and one month following CAR-T (M1). Seurat v4.3.0 was used for unsupervised hierarchical clustering analysis. Lugano criteria was used to determine clinical responses which were categorized as CR (complete remission), PD1, or PD2. Results We analyzed 129,981 monocytes from 77 samples of 32 pts (16 CR, 4 PD1, 12 PD2) and 5 healthy controls. Unsupervised hierarchical clustering analysis identified 13 monocyte clusters: 4 classical monocyte (CM) clusters with transcriptome profiles for enriched signaling in IL-6, TGFβ, EMT, and p53; 2 intermediate monocyte (IM) clusters enriched for IL-1 or CD38 signaling; 2 non-classical monocytes (NM), one with increased CD36 expression; 3 monocytic MDSC clusters with enrichment of TGFβ, SIRPα, and HIF1α signaling; and 2 lymphoma-associated monocytes, expressing CD163 or CD169. At Pre and Peak, the distribution of the monocyte clusters was similar in pts with CR, PD2, or PD1, with only a slight decrease in the percent of NM in the PD2 group at Pre and slight increase of CD36 NM in PD1 at Peak. Compared to Pre, all pts had increased percent of CD36 NM and IL-1 IM at Peak. Interestingly, while the distribution of monocyte clusters was similar at Pre and Peak across clinical responses, GSEA showed that monocytes in CR pts, compared to PD1 and PD2, had gene expression enrichment of MYC target V2 pathway at Pre and TGFβ pathway at Peak. At M1, pts in PD1 had increased percent of p53 and TGFβ CM and decreased percent of NM. In contrast, pts with CR had decreased percent of IL-6 CM, p53 CM, TGFβ CM, IL-1 IM and increased percent of NM. Notably, as pts with CR and PD2 may appear similar clinically at M1, pts with PD2, compared to CR, have increased IL-6 CM, IL-1 IM, and decreased NM. In addition, GSEA showed that PD2 pts had increased IFNα response. Our results demonstrate that monocyte phenotype differences at Pre and Peak could be associated with CAR-T clinical response, and that persistent inflammatory monocyte signaling at M1 in pts with clinical response is associated with relapse. These data suggest a role for development of monocyte biomarkers to predict response and therapeutic targeting. Citation Format: Andre de Menezes Silva Corraes, Panwen Wang, Radhika Bansal, Henan Zhang, Zuoyi Shao, Kevin Regan, Eider Moreno Cortes, Arushi Khurana, Nora Bennani, Yucai Wang, Paul Hampel, Jonas Paludo, Patrick Johnston, Hemant Murthy, Madiha Iqbal, Stephen Ansell, Javier Munoz, Allison Rosenthal, Mohamed Kharfan-Dabaja, Januario Castro, Saad Kenderian, Haidong Dong, Ying Li, Yi Lin. Monocyte transcriptome profiles associated with clinical response in patients with B-cell non-Hodgkin’s lymphoma receiving CD19-directed CAR-T therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4001.