Clinical outcomes with 14- vs 28-day monitoring after CAR-T therapy.

e13590 Background: The US Food and Drug Administration recently eliminated the Risk Evaluation and Mitigation Strategies (REMS), which increased monitoring for cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) following chimeric antigen receptor T-cell (CAR-T) therapy. As a result, the time a patient must remain near the authorized treatment center (ATC) post infusion was reduced from four weeks to two weeks. Our hypothesis was there will be no difference between CRS/ICANS, mortality, readmission rates, and infection rates between the 28 day vs 14 day monitoring period cohorts. Methods: We performed a retrospective review of 42 adult patients who underwent CAR-T therapy at the University of Kansas Medical Center. Endpoints of CRS/ICANS prevalence, ICU admission, 30 day readmission, and 30 day infection were compared between 14 day and 28 day discharge cohorts using Fisher’s exact test for categorical variables and Wilcoxon rank-sum tests for continuous variables. Overall survival was estimated by Kaplan–Meier methods and compared using the log-rank test. Multivariable logistic regression adjusting for age and care setting was performed for selected outcomes. Results: 42 patients underwent CAR-T therapy, 22 of which discharged at 14 days and 20 at 28 days. Median follow-up was 3.3 months (14-day) and 8.4 months (28-day). Baseline characteristics and CAR-T products were comparable between groups. There were no statistically significant differences in rates of any CRS (81.8% vs 75.0%, p = 0.714), CRS grade ≥2 (16.7% vs 0%, p = 0.233), any ICANS (36.4% vs 55.0%, p = 0.352), ICU admission (13.6% vs 31.6%, p = 0.260), 30 day readmission (54.5% vs 30.0%, p = 0.131), or 30 day infection (13.6% vs 10.5%, p = 1.000) for 14 day vs 28 day discharge, respectively. Overall response rates and complete response rates at day 30, day 90, and best overall response were similar between cohorts. There were no deaths within 30 days in either group, and 31–90 day mortality did not differ significantly. Multivariable analyses adjusting for age and care setting showed no significant association between discharge timing and readmission, ICU admission, CRS, or ICANS. Conclusions: Our results suggest the elimination of REMS did not adversely impact patient safety: there was no significant increase in rates of CRS, ICANs, ICU admission, 30 day readmission, and 30 day infection between the 14 day and 28 day monitoring cohorts. Limitations of this study include small sample size and a short median follow-up, due to the small cohort of patients who have received CAR-T since the REMS elimination in June 2025. Although the median follow-up is limited, based on the literature we would expect the main safety signals for this change to manifest by day 90, which was reached in both groups. Future research should probe if similar findings occur in larger cohorts or for longer monitoring periods, especially as more time passes since the updated guidance.