Abstract

7033 Background: Prior studies have described toxicities associated with chimeric antigen receptor T cell therapy (CART). Recently, myeloid malignancies were identified in myeloma patients (pt) after receipt of cilta-cel. In this study, we sought to describe the cumulative incidence and characteristics of secondary myeloid malignancies in pt treated with CART for NHL. Methods: We conducted a single institution retrospective study among pt ages ≥18 years (yr) who received commercial CART for NHL at Ohio State between December 2017 to April 2022. Descriptive statistics were used to summarize pt/disease characteristics. Cumulative incidence was calculated from date of infusion with death/relapse as competing risks. Results: For 190 pt treated with CART, median age was 63 yr (23-85 yr). Disease subtypes included diffuse large B-cell lymphoma (BCL)/high grade BCL, Richter transformation, and mantle cell lymphoma (79.5%, 8.4%, and 7.4%). Products included tisa-cel (47.9%), axi-cel (43.1%), brexu-cel (7.4%), and liso-cel (1.6%). Grade 3-4 neutropenia developed in 29% and 18% of pt at 30 days and 90 days post-CART. Median follow-up was 17 mo (0.5-63 mo). 48% were alive at time of analysis. Myeloid malignancy post-CART occurred in 7 pt with a median time to development of 29 mo (18-41 mo). Characteristics (Table) included complex karyotype, TP53 and chromosome 5/7 abnormalities. Cumulative incidence of secondary malignancy was 1%, 5%, and 6% at 2, 3, and 4 yr post-CART. Conclusions: We report on incidence of secondary myeloid malignancy in pt receiving CART for NHL. Mutational characteristics of secondary malignancies were those classically associated with therapy-related myeloid malignancy, thus presumed to be associated with prior exposure to chemotherapy (eg. alkylators/VP-16). Further investigation in larger cohorts with additional observation time, to allow for appropriate risk discussion, is required. [Table: see text]