Durani, Urshila

Background: Approximately20% of patients with follicular lymphoma (FL) will experience disease progression or death within two years of years (POD24) of immunochemotherapy (IC) (Casulo et al, JCO 2015). A proportion of patients with POD24 have histologic transformation (HT), which heightens the risk of lymphoma-related death (Freeman et al, Blood 2019). To clarify the impact of HT on prognosis in POD24, we analyzed data from the Lymphoma Epidemiology of Outcomes (LEO) Consortium of Real-World Evidence (CReWE) to compare differences in outcomes among patients with POD24 with retained FL histology versus POD24 with HT. Methods: This was a multicenter study among 8 academic cancer centers. Eligible patients hadgrade 1-3a FL at diagnosis between 2003 and 2022, with POD24 following first line IC treatment with BR, R-CHOP, or R-CVP. POD24 was defined as disease recurrence within 24 months of IC. Patients with prior lines of treatment for FL were excluded. Patients with HT at first line IC were excluded. Biopsy at POD24 was obtained at the discretion of the treating physician. Three groups of POD24 were defined: POD24 with biopsy-proven retained FL histology (POD24_FL), POD24 with biopsy-proven HT to aggressive lymphoma (POD24_HT), and POD24 either without a biopsy or indeterminate histology on biopsy (POD24_I). We evaluated second-line treatments at time of POD24. Survival probabilities from second-line treatment initiation were estimated by the Kaplan-Meier method. Results A total of1,122 patients with FL were screened and308 patients with POD24 were identified.Median age at POD24 was 58 years (IQR 50-65).Among available data, race and ethnicity was reported as 76% non-Hispanic White, 3% non-Hispanic Black/African American, 9% Hispanic/Latino (any race), and 1% other minorities. First line therapy was R-CHOP in45% (140/308), BR in 33% (102/308) and R-CVP in 21% (66/308). Most patients (52%) had biopsy-proven retained FL at POD24 (162/308); 30% had no biopsy or indeterminate histology at POD24 (94/308), and 17% had biopsy-proven HT at POD24 (52/308). In the POD24_HT group, 52% received R-CHOP and 21% received intensive salvage chemotherapy as second line therapy. Patients with POD24_FL and POD24_I had similar rates of salvage chemotherapy (21% and 18%), BR (13% and 18%), R-CHOP (19% and 24%), and targeted therapies (8% and 5%), respectively, at second line. Consolidative autologous stem cell transplant was more common in POD24_HT patients at 21% versus 16% in POD24_FL and 6% in POD24_I. Patients with POD24_HT had significantly worse overall survival (OS) compared to POD24_FL (ref), with a hazard ratio of 3.79 (95% confidence interval [CI] 2.46-5.84), even after adjusting for age, FLIPI score, and first-line IC treatment. At 5 years, patients with POD24_HT had OS of 31% compared with an OS of 71% for patients with POD24_FL. Patients with POD24_I had similar outcomes to those with POD24_FL (5-year OS 75% versus 71%, respectively). Event-free survival (EFS) was also significantly lower in POD24_HT compared to POD24_FL: At 2 years, EFS was 27% for POD24_FL (21-35%) and 10% for POD24 _HT (4-23%). At 5 years, lymphoma remained the leading cause of death among patients with POD24, with 20% probability of lymphoma-related death in those with POD24_FL (95% CI 14.2-27.8) compared to 53% probability of lymphoma-related death in patients with POD24_HT (95% CI 40.6-70.7). Conclusions: In our multicenter cohort, we identified remarkable differences between the two biopsy-demonstrated entities of POD24 (i.e., with and without HT). Patients without a biopsy or indeterminate histology had similar outcomes as those with POD24_FL. Patients withearlyrelapse of FL after first-line IC remain a heterogeneous group with poor outcomes and a heightened risk of lymphoma-related mortality particularly compared with nonPOD24 groups. Even with retained FL histology, patients with POD24 had 20% probability of lymphoma-related death within 5 years of second-line treatment initiation. We demonstrate that poor survival is driven in part, but not entirely, by HT. Despite most patients receiving appropriate aggressive treatment, those with POD24_HT represent a distinctly vulnerable population warranting further study in directed prospective studies of both FL biology and clinical trials.

Background and Methods: IEC-HS is a hyperinflammatory state with high morbidity and mortality. Effective interventions to reverse the process early in the clinical course may be critical to improve outcomes. We previously examined cytokine differences between IEC-HS and other secondary hemophagocytic lymphohistiocytosis, and found significant differences in the patterns and outcomes.(1) This study examines cytokine profiles (CP) of patients treated with CAR-T from 9/2019 to 3/2024 who developed CRS, MAS-L and IEC-HS. Demographics and lab results were compared among the three groups and correlated with outcomes. Results: CP was tested in 113 of 366 CAR-T patients: 74 with CRS, 19 with MAS-L, and 20 with IEC-HS. The racial distribution was 93% White/Caucasian, 2% Black or African American, 1% Asian, 1% Native American and 3% other or unavailable. No differences were seen in demographics between groups except a higher percentage of patients with ECOG performance status ≥2 in IEC-HS (p=0.037). Incidence of IEC-HS by disease: 3.6% (7/193) in lymphoma, 5% (8/159) myeloma and 28.5% (4/14) B-acute lymphoblastic leukemia (p=0.0002). Incidence of IEC-HS by CAR-T product: 3% (4/150) in Axi-cel, 23% (6/26) in Brexu-cel, 8% (1/13) in Tisa-cel, 5% each (3/60) in Cilta-cel and Ide-cel, and 0/17 in Liso-cel (p=0.001). Prior to lymphodepletion, labs were already different among the CRS, MAS-L, and IEC-HS groups: hemoglobin (g/dL: 11.1, 9.6, 8.45); platelets (x109/L: 168, 116, 52.5); ferritin (µg/L: 115, 946, 1944). CP was started when patients needed a second dose of tocilizumab or concern for developing MAS-L/IEC-HS, and continued daily until clinical improvement or resolution of inflammatory state. Tocilizumab and dexamethasone use were similar across groups. Other therapies used were vasopressors (3%, 10.5%, 45%; p<0.0001), Methylprednisolone (20%, 31.6%, 50%; p=0.027), Anakinra (12%, 63%, 85%; p<0.0001), Siltuximab (9.5%, 16%, 30%; p=0.06), Basiliximab (30% of IEC-HS), and continuous veno-venous hemofiltration (30% of IEC-HS). Among the first CP, the CRS group had lower levels of cytokines (in pg/mL) compared to MAS-L and IEC-HS groups: TNF (31, 62.9, 47.7), IL-10 (29.3, 97.7, 169), IL-18 (794, 1353, 2011), IFN-gamma (74, 281, 250), MCP-1 (689, 2722, 2485.5), MIP-1 alpha (220, 234, 247.5), IL-6 (>315: 45%, 79%, 70%), soluble IL-2R alpha (>4000: 45%, 84%, 70%). The percentage of patients who received anakinra before CP1 were 4% (CRS), 21% (MAS-L) and 25% (IEC-HS) (p=0.007). IL-1 beta was below threshold among all patients who received anakinra in CRS and MAS-L and 75% in IEC-HS, suggesting rapid and effective IL-1 suppression by anakinra except in IEC-HS. Cytokines trends 24 hours and 48 hours after the first CP differed between MAS-L and IEC-HS. MAS-L had decreased TNF (62.9, 40.4, 18.5) and MCP-1 (2722, 355, 104) while these cytokines remained elevated or increased in IEC-HS (TNF: 47.7, 105.5, 62.6; MCP-1: 2486, 2276, 1585). IL-18 was minimally elevated in MAS-L (1353, 1955, 3068) and significantly increased in IEC-HS (2011, 2420, 4048). Notably, CP2 and CP3 levels of these cytokines in IEC-HS were statistically significantly higher than corresponding CPs among CRS and MAS-L. In addition, patients who died with persistent E. faecium bacteremia had higher IL-18 on CP3. Infections occurred in 43%, 58%, and 85% respectively (p=0.002), including E. faecium bacteremia (3%, 5%, 35%; p=0.0004), CMV viremia (30% of IEC-HS patients vs. 11% of non-IEC-HS; p=0.025), and invasive fungal infections (15% of IEC-HS patients; p=0.0001). Between the IEC-HS and non-IEC-HS groups, day 100 non-relapse mortality was 35% vs. 0 (p<0.0001), day 100 all-cause mortality was 45% vs. 3% (p<0.0001), and E. faecium bacteremia-related deaths were 50% vs. 1% (p<0.0001). Conclusions: CRS, MAS-L andIEC-HS are known complications of CAR-T. Cytokine-directed therapy can modify the cytokine milieu and control the inflammatory process. However, excess immunosuppression may result in life-threatening infections. Further studies are needed to identify optimal biomarker-guided immunosuppressive strategies to control the inflammatory cascade, while avoiding excess immunosuppression. References: 1. Leung, Nelson, et al. “Outcomes of patients who received CAR T cell therapy and developed IEC-HS treated with cytokine directed therapy.” (2024): 7516-7516.

Background: Due to recent advances, patients with follicular lymphoma (FL) have multiple treatment options with high response rates and durability. However, there is a gap in understanding how patient preferences influence treatment selection. To close this gap, we conducted a qualitative study using focus groups of adults with FL to understand their knowledge of treatment options, priorities, and decision-making process. We designed this study to inform the content of a planned discrete choice experiment in a larger population of patients with FL to better understand patient preferences and trade-offs around treatment delivery, side effects, outcomes, and quality of life. Methods: We conducted focus groups lasting 60-90 minutes, each with 3-5 participants recruited from the Lymphoma Epidemiology of Outcomes (LEO) Cohort Study. The LEO Cohort Study is a multi-institutional prospective cohort study of newly diagnosed adults with non-Hodgkin lymphoma from July 2015 to present. Each focus group was co-led by two investigators (U.D. and M.T.) and conducted using Zoom video technology. Participants were asked to comment on their understanding about FL and available treatments, their ideal treatment, their decision-making process about prior therapies, and quality of life and side effects associated with treatment. We performed exploratory content analysis of participant understanding of FL and their treatment preferences. We will continue to conduct focus groups until we reach thematic saturation, which we anticipate will occur with one additional focus group. Themes from all focus groups were identified and agreed upon by both investigators (U.D. and M.T.) and were verified by additional investigators (J.D., M.L, M.H., B.K.L, C.C., M.M.). Results: To date, we conducted five focus groups with a total of N=21 participants (median age 60 [range 41-88], 66.7% female, 71.4% non-Hispanic White, 14.3% Hispanic, 9.5% Asian, 4.8% Black/Hispanic). We identified the following themes and representative quotes: 1) Holistic approach:Participants wanted their oncologists to view their care from a holistic perspective, discussing their individual priorities and options that would accommodate their fitness routine and ability to work. “[I wish] if doctors can consider not just the physical choices, but also the mental and emotional choices as well, the holistic person.” - Participant 13 “There's zero chance I can go back to working in the type of career where other people rely on me for things. I can't keep things straight.” - Participant 16 2) Ideal treatment:An ideal treatment would limit impact on fatigue, cognitive function, and have minimal toxicity to preserve quality of life and an active lifestyle. “I would say something that has minimal impact on daily life would be ideal and something that would make you feel better.” - Participant 6 3) Shared decision-making: Participants wanted to be better informed about available treatment options and often utilized second opinions to inform their decisions. “It helped to get the second opinion versus not. It would've been a completely different set of events.” - Participant 17 4) Treatment burden:Financial impact and effort required by patients to receive care (e.g., travel, number of office visits, and duration of therapy) were key factors in patient decision-making. “Part of my quality of life went down because I had to fight with my insurance company consistently, and we pay a lot of money.” - Participant 11 “Really explain the time options and calendarize the treatment and be more specific about the amount of time that you're going to spend at the hospital and the process.” - Participant 20 5) Representation: Minority participants raised concerns about not knowing if the available treatment data pertained to them. “[My end-goal would be] having an understanding of how the treatment is going to be for minority people. Many times the treatments are tested, they are not tested for minorities.” - Participant 21 Conclusions: The patient perspective is critical for treatment decision-making and education. People living with FL expressed a desire for a holistic and individualized approach to treatment decision-making that incorporated their lifestyle, minimized side effects, and limited overall treatment burden. These focus groups identified emerging themes that warrant further investigation for survivors with FL.

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.

Abstract Progression of disease within 24 months of initial immunochemotherapy (POD24) is a negative prognostic factor for patients with follicular lymphoma (FL). There is no standard treatment after POD24. Assembling an academic-based cohort from the Lymphoma Epidemiology of Outcomes Consortium for Real World Evidence, we evaluated patterns of care and outcomes for 220 patients with FL with POD24 and retained FL histology. Therapy after POD24 was heterogeneous, with no treatment category accounting for >25% of the total. Among patients initially treated with bendamustine-rituximab, rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP) was the predominant second-line choice (48%). Among patients initially treated with R-CHOP, aggressive salvage therapy was the predominant second-line choice (38%). Overall response rate to therapy after POD24 was 64% (95% confidence interval [CI], 56-70); complete response rate was 39% (95% CI, 32-46). The median event-free survival for therapy after POD24 was 9.8 months (95% CI, 7.3-12.1); 5-year overall survival (OS) was 71% (95% CI, 65-78). OS was inferior for patients aged >70 years (hazard ratio [HR], 2.31; 95% CI, 1.27-4.20) and those with high-risk FL International Prognostic Index scores at diagnosis (HR, 2.10; 95% CI, 1.23-3.60). No treatment category stood out with more favorable results. Cause of death was predominantly lymphoma related. Patients with follicular histology at their POD24 event had a low cumulative incidence of transformation (1.1% at 5 years). Our study is among the largest cohorts describing contemporary patterns of care for patients with POD24, providing a focused data set useful for interpreting and designing prospective clinical trials in this population.

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.

The infusion autograft absolute number of inhibitory killer immunoglobulin-like receptor (KIR) 2DL2 and activating natural killer (NK)p30 cells are predictors of clinical outcomes in lymphoma patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). To assess if the long-term recovery of these NK cell subsets still holds clinical relevance, we set up to investigate their prognostic ability at day 100 post-APBHSCT. This was a retrospective single-institution study including 107 patients from our prior phase III trial who had a clinical assessment at day 100 post-APBHSCT. The median follow-up from day 100 was 168.19 months (interquartile range: 156.85–181.28 months). Patients with day 100 inhibitory KIR2DL2 < 0.08 cells/µL and activating NKp30 ≥ 0.19 cells/µL experienced superior overall survival (OS) and progression-free survival (PFS). A multivariate analysis revealed both the day 100 inhibitory KIR2DL2 [OS: HR = 1.449, 95%CI, 1.231–1.895, p < 0.013; and PFS: HR = 2.069, 95%CI, 1.134–3.775, p < 0.021] and activating NKp30 [OS: HR = 4.985, 95%CI, 2.614–9.506, p < 0.0001; and PFS: HR = 4.661, 95%CI, 2.598–8.393, p < 0.0001] were independent predictors for OS and PFS. Inhibitory KIR2DL2 and activating NKp30 NK cells at day 100 are prognostic immune biomarkers in lymphoma patients treated with APBHSCT.

7516 Background: Immune effector cell hemophagocytic lymphohistiocytosis IEC-HS is a complication of CAR T cell therapy (CART). This study aims to look at the outcomes of CART patients who develop IEC-HS. Methods: Patients who developed IEC-HS after receiving CART and patients who developed IEC-HS without (nonCART) between December 2020 and March 2022 were included. Results: The 20 CART patients were older than the 25 nonCART patients. Peak ferritin, fibrinogen, CRP, serum creatinine and transaminases were similar between the 2 group. CART patients had lower white blood cell count and platelets and bilirubin than the nonCART patients. CART patients were more like to have markedly elevated IL-6 levels (> 315 mg/ml), higher IL-18, higher MCP-1, and suppressed IL-1β and GMCSF than nonCART patients (Table). Treatment of IEC-HS included tocilizumab (n = 19), anakinra (n = 18) siltuximab (n = 4) and basiliximab (n = 4), dexamethasone (n = 18) methylprednisolone (n = 6), etoposide (n = 1) and ruxolitinib (n = 1). A significant response defined by a 90% reduction or normalization of the cytokine was observed with IL-10 and IFN-ϒ in 92.3% and 84.6% of the CART patients respectively. An intermediate response was noted with TNF, IL-6, MCP-1 and MIP-1 in 38.4%, 30.8% and 61.6% and 38.5% of the patients respectively. No patient had a significant response in IL-2Rα or IL-1β and only 7.7% had a significant response in IL-18. Of the 5 patients who had a MIP-1 response, 4 were on basiliximab +/- high flow continuous venovenous hemofiltration and the only patient that had an IL-18 response was on both modalities. The 100-day mortality after IEC-HS in the CART patients was 40% and was associated with higher peak and lower best ferritin but not the percentage reduction (Table). Higher TNF (90.3 pg/ml vs 37.2 pg/ml, p = 0.05), markedly elevated levels of IL-6 (92% vs 50%, p = 0.03) and IL-10 (33% vs 0%) and an IL-6 response (44.4% vs 0%) were associated with survival at day 100. IL-6 responders had lower peak ferritin vs IL-6 nonresponders (14066 mcg/L vs 45051 mcg/L, p = 0.08). Enterococcus faecium bacteremia developed in 75% of the nonsurvivors vs 16.6% of the 100-day survivors (p = 0.009). Survivors cleared the enterococcus bacteremia within days while nonsurvivors had protracted bacteremia. Conclusions: IEC-HS is devastating complication of CART. Anti-cytokine therapy can reduce some cytokines and ferritin but overimmunosuppression may lead infectious complication, in particular with E. faecium. Better biomarkers are needed to finetune immunosuppressive therapy in order to avoid over-immunosuppression. [Table: see text]

7038 Background: While chimeric antigen receptor T-cell (CAR-T) therapy has transformed treatment for hematological malignancies, severe (≥ grade 3,Gr 3, CTCAE) cytopenias post CAR-T and therapy related myeloid neoplasms (t-MN) are particularly difficult to manage. Survival after diagnosis of t-MN is dismal. Management of ≥Gr 3 cytopenias that do not recover by month 3 after CAR-T require frequent monitoring and transfusion support. Growth factor and thrombopoietin mimetics have variable success, with stem cell boost emerging as having more consistent success. Evaluation for CAR-T eligibility, prior to leukapheresis, is the critical timepoint where factors identified at this time could inform risks and benefits of CAR-T versus alternative treatment and for consideration of stem cell collection in patients who may benefit from stem cell boost to treat severe cytopenia post CAR-T. Methods: We conducted a retrospective analysis comparing clinical data of patients (pts) with lymphoma (NHL) and multiple myeloma (MM) treated with FDA-approved and investigational CAR-T between 01/2016 – 06/2022 at Mayo Clinic. Prolonged cytopenias were defined as hemoglobin (Hg)<8 g/dL, absolute neutrophil count (ANC)<0.5 x 109/L, and/or platelet count (PLT)<50 x 109/L at 3 months after CAR-T. Pts with progressive disease were excluded from cytopenia analysis. Logistic regression to identify factors correlated with cytopenia and t-MN. Results: Among the 186 pts who received CAR-T, 42 (22%) patients developed severe cytopenia (26/102, 25%, in NHL; 16/84, 19% in MM); 15/186 (8%) had more than 1 concurrent cytopenia. Univariate analysis identified that baseline ferritin and CAR-HEMATOTOX score correlated with cytopenia. Multivariate analysis showed that advanced age (≥ 65 years) (HR 2.69, 95%CI 1.17 – 6.40, P = 0.02) and thrombocytopenia (HR 4.01, 95%CI 1.77 – 9.34, P = 0.001) were associated with severe cytopenia. Twenty (10.7%) patients [8 (40%) males] developed t-MN at a median of 9.5 months (IQR 4.8 – 19.3 months) after CAR-T (14/102, 13% in NHL; 6/84, 7% in MM). Univariate analysis identified ferritin and CAR-HEMATOTOX score correlated with t-NM. Multivariate logistic regression showed advanced age (HR 5.03; 95%CI 1.59-18.7, P= 0.009), hemoglobin ≤ 10 g/dl (HR 3.63, 95%CI 1.04-13.30, P = 0.04), and thrombocytopenia (HR 4.06, 95%CI 1.32-14.2, P 0.02) are significantly associated with development of post-CART t-MN. Conclusions: Advanced age, anemia and thrombocytopenia at the time of evaluation for CAR-T eligibility, prior to leukapheresis, are associated with the development of post-treatment severe cytopenia and t-MN. Larger, multi-center studies are needed to validate these findings.

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.