Hematologic toxicities with axicabtagene ciloleucel for B cell lymphomas in a majority minority population.

e19011 Background: Chimeric antigen receptor (CAR) T-cell therapy for B-cell lymphomas is increasing in use and predictive tools, like CAR-HEMATOTOX, help identify patients at risk for prolonged neutropenia (NP). This tool, validated in two cohorts, lacks confounding by race, but applicability to minority populations is unknown. Here we describe hematologic toxicities and evaluate possible predictors of toxicity in patients who received axicabtagene ciloleucel (AC) in a majority minority population. Methods: We conducted a single-center retrospective analysis of adults ≥ 18 years who received AC at Montefiore Einstein Comprehensive Cancer Center in the Bronx, NY. Descriptive statistics were used to define patient characteristics. Univariate linear regression models were used to evaluate possible predictors of hematologic toxicity. Statistical analyses were performed using R programming. Results: Between June 2018 and December 2024, 81 patients received AC; 23 (28%) identified as Hispanic, 19 (23%) non-Hispanic Black, 27 (33%) non-Hispanic White, four (5%) Asian/Pacific Islander, and eight (10%) were self-identified as other race/ethnicity. 35 patients (43.2%) experienced profound NP (absolute neutrophil count [ANC] < 100 cells per µL) and 73 patients (90.1%) experienced severe NP (ANC < 500 cells per µL). The median duration of severe NP was 8 days (range 0 - 49 days). On univariate analysis lower baseline white blood cell count (WBC) and ANC measured 30 - 40 days prior to AC significantly correlated with duration and severity of NP (p < 0.01). WBC and ANC were highly correlated; WBC was a surrogate for ANC. Lower hemoglobin level on the day of infusion (D0) also significantly correlated with duration of NP (p < 0.05), not with severity. Baseline c-reactive protein (n = 64) and ferritin (n = 52) did not correlate with duration or severity of NP. Age at the time of CART infusion, sex (male or female) and race did not correlate with either outcome, but number of previous lines of treatment correlated with both duration (p < 0.01) and severity (p < 0.05). 32 out of 81 patients (39.5%) were classified as low-risk and 49 (60.5%) as high-risk based on the CAR-HEMATOTOX model. Neither CAR-HEMATOTOX score nor risk class correlated with duration or severity of NP. Each factor was a poor predictor of duration or severity of NP based on the models adjusted r 2 value. The best predictor of severity of NP was the WBC on the D0 (r 2 = 0.30), and of duration of NP was the number of lines of previous treatment (r 2 = 0.11). Conclusions: CAR-HEMATOTOX is a tool to stratify patients likely to have cytopenias, and in this majority minority population it did not correlate with severe or prolonged NP after AC. We plan to expand these results to include patients who received other CAR-Ts, and to describe the prevalence of non-hematologic toxicities. Further studies are needed to predict cytopenias after CAR-T, especially as outpatient CAR-T is explored.