Comparative assessment of colitis-related adverse events in multiple myeloma patients treated with teclistamab, ciltacabtagene, and idecabtagene: Incidence, outcomes, and risk assessment.

e19510 Background: Colitis, an inflammation of the colon, is a significant adverse event (AE) increasingly seen in patients with multiple myeloma treated with novel immunotherapies, such as bispecific antibodies (e.g., teclistamab) and CAR T-cell therapies (e.g., ciltacabtagene). While these treatments have improved management of hematological malignancies, they are often associated with gastrointestinal toxicities, including colitis. If left untreated, colitis can lead to severe complications, such as prolonged hospitalizations, increased morbidity, and even death. Understanding the incidence, clinical manifestations, and outcomes of colitis-related AEs is vital for optimizing management strategies. Methods: This retrospective analysis compares clinical manifestations and outcomes of colitis in patients treated with teclistamab, ciltacabtagene, and idecabtagene, using FDA-reported AEs from Q1 2020 to Q3 2024. Colitis cases, including immune-mediated enterocolitis and Clostridium difficile infections, were analyzed for frequency, severity, and outcomes such as hospitalization, death, and recovery. The study also examined potential risk factors for these AEs, considering the complexity of immunotherapies. Results: Out of 5,525 patient reports, teclistamab was associated with 1,885 reports, ciltacabtagene with 1,770 reports, and idecabtagene with 870 reports. Teclistamab had the highest colitis incidence at 0.85%, including 5 Clostridium difficile cases (0.26%) and 2 immune-mediated enterocolitis cases (0.11%). Ciltacabtagene had 13 colitis cases (0.73%), with a broader range of GI issues like Crohn’s disease and ulcerative colitis. Idecabtagene had 0.57% colitis cases, primarily Clostridium difficile. Teclistamab had 23 hospitalizations (1.22%) and 5 deaths (0.27%), while ciltacabtagene showed 21 hospitalizations (1.19%) and 7 deaths (0.40%), indicating a higher mortality rate. Idecabtagene had the lowest incidence of both hospitalizations (3, 0.34%) and deaths (1, 0.11%), suggesting a more favorable safety profile. Conclusions: This analysis reveals notable differences in colitis-related AEs among patients treated with teclistamab, ciltacabtagene, and idecabtagene. Teclistamab showed the highest rates of severe colitis, including immune-mediated enterocolitis and Clostridium difficile infections. Ciltacabtagene had a broader spectrum of GI-related AEs and higher mortality rates, requiring careful monitoring. Idecabtagene demonstrated a milder safety profile, suggesting it may be more suitable for patients at higher risk for GI toxicities. These findings highlight the need for drug-specific risk assessments, vigilant monitoring, and further research to improve patient outcomes and understand the mechanisms of GI AEs.