Immune-mediated colitis after resumption of immune checkpoint inhibitor therapy

2577 Background: Immune checkpoint inhibitor (ICI) therapy is often suspended because of immune-mediated diarrhea and colitis (IMDC). We examined the recurrence rate and risk factors for IMDC after ICI resumption. Methods: This retrospective multicenter study examined patients who resumed ICI therapy after improvement of IMDC between 1/2010 and 11/2018. Univariate and multivariate logistic regression analyses assessed the association of clinical covariates and IMDC recurrence. Results: Of the 167 patients in our analysis, 32 resumed an anti-CTLA-4 agent and 135 an anti-PD-1/L1 agent. The median duration from IMDC to restart of ICI treatment was 49 days (IQR, 23-136). IMDC recurred in 57 (34%) patients overall (44% of those resuming an anti–CTLA-4 and 32% resuming an anti–PD-1/L1 agent); 47 of these patients (82%) required immunosuppressive therapy for recurrent IMDC (Table). The median duration from ICI resumption to IMDC recurrence was 53 days (IQR 22-138). On multivariate logistic regression, patients who received anti-PD-1/L1 therapy at initial IMDC had a higher risk of IMDC recurrence (odds ratio [OR], 3.45, 95%CI, 1.59-7.69; P