Joseph Sleiman, MD, Ravi Shah, MD, Wei Wei, MSc, Pauline Funchain, MD, Jessica Philpott, MD, Roberto Simons-Linares, MD, MS
Cleveland Clinic Foundation, Cleveland, OH
Introduction: Immune checkpoint inhibitors (ICI) have shown efficacy in the treatment of a growing number of cancers resulting in increasing numbers of patients exposed. ICI-related colitis (ICI-colitis) is a common ICI-related adverse event and mimics inflammatory bowel disease (IBD). In this study, we report the rate of colitis in patients with cancer receiving ICI with pre-existing IBD or microscopic colitis (MC).
Methods: We retrospectively reviewed 1672 patients who underwent ICI therapy for cancer at a tertiary center since January 2011. We included patients who had a baseline IBD or MC diagnosis. Demographic data, clinical history of IBD, MC, cancer, ICI treatment, colitis events after ICI therapy and overall survival (OS) were analyzed. OS and time to colitis were estimated by Kaplan-Meier method.
Results: We identified 13 patients who had either IBD or MC. Among 11 IBD patients, 7 (64%) were on chronic therapy. ICIs were mostly PD-1/PD-L1 inhibitors monotherapy (10, 91%). Six (55%) patients developed colitis at a median of 17 (95% CI: 5-NA) weeks after ICI initiation. Imaging and endoscopy were done in 4 (66%) and 3 (50%) of cases, respectively. Ruling out C. difficile infection was performed in 2 (33%) of cases before starting steroid therapy, and laboratory testing (CRP and ESR) was done in 2 (33%) cases. No case had fecal calprotectin, lactoferrin or enteric PCR testing. 4 (80%) and 5 (100%) of 5 patients on steroid regimens had tapers over at least 6 or 4 weeks, respectively. ICIs were resumed in 2 cases. No case diagnosed as IBD flare was re-challenged with ICIs. In contrast, both patients with MC were on chronic treatment with 5-ASA and local steroid. One of the 2 patients with MC developed grade 1 ICI-colitis within 18 weeks and is still receiving ICI therapy. Median follow-up was 25 months (range: 18-29). Median OS was 12 (95% CI: 2-NA) months.
Discussion: In our cohort 50-55% of patients with preexisting inflammatory conditions of the intestines developed colitis while on ICIs. This proportion is higher than reported rates of ICI-induced colitis, which range from 0.5-20% in the general population, to 5.2-20% among patients with autoimmune disorders. Further studies require clarification of risk and identification of means to modify risk in order to allow these patients to benefit from cancer therapy.
Citation: Joseph Sleiman, MD, Ravi Shah, MD, Wei Wei, MSc, Pauline Funchain, MD, Jessica Philpott, MD, Roberto Simons-Linares, MD, MS. P0476 - IMMUNE CHECKPOINT INHIBITOR RELATED COLITIS (ICI-COLITIS) IN PATIENTS WITH PREEXISTING INFLAMMATORY BOWEL DISEASE OR MICROSCOPIC COLITIS. Program No. P0476. ACG 2019 Annual Scientific Meeting Abstracts. San Antonio, Texas: American College of Gastroenterology.