P2612 - Initial Endoscopic Presentations of Immune Checkpoint Inhibitor Colitis and Their Differential Disease Outcomes

Malek Shatila, MD¹, Andres Rivera, MD², Kian Abdul-Baki, DO³, Linfeng Lu, MD², Kei Takigawa, MD², Carolina Colli Cruz, MD⁴, Raakhi Menon, DO³, Elliot Axel. Baerman, MD², Andrew Sullivan, MD⁵, Tanvi Gupta, MD⁶, Hamza Salim, MD³, Varun Vemulapalli, MD⁶, Irene J. Lee, MD², Ayesha Khan, DO³, Cristina M. Natha, MD⁶, Krishnavathana Varatharajalu, MD¹, Garrett T. Coleman, ⁷, Dan Zhao, MD⁸, Anusha Thomas, MD¹, Yinghong Wang, MD, PhD^8
1The University of Texas MD Anderson Cancer Center, Houston, TX; ²Baylor College of Medicine, Houston, TX; ³University of Texas Medical Branch, Galveston, TX; ⁴MD Anderson Cancer Center, Houston, TX; ⁵University of Texas Health Science Center, Houston, TX; ⁶University of Texas Health, McGovern Medical School, Houston, TX; ⁷University of Texas Medical Branch, John Sealy School of Medicine, Galveston, TX; ⁸University of Texas MD Anderson Cancer Center, Houston, TX

Introduction: Immune-mediated colitis (IMC) is a frustrating toxicity to immune-checkpoint inhibition that frequently necessitates the discontinuation of treatment. While pathophysiologically similar to inflammatory bowel disease, IMC has a unique spectrum of clinical, endoscopic, and histological presentations that are not fully understood. Few studies compare clinical disease characteristics and treatments amongst different IMC presentations. In this study, we aim to compare the differential disease behavior of IMC with normal, histopathologic, or macroscopic endoscopic presentations.

Methods: Immune-mediated colitis (IMC) is a frustrating toxicity to immune-checkpoint inhibition (ICI) that frequently necessitates the discontinuation of treatment. While similar to inflammatory bowel disease, IMC has a unique spectrum of clinical, endoscopic, and histological presentations that are not fully understood. In this study, we aim to compare the differential disease behavior of IMC with normal, histopathologic, or macroscopic endoscopic presentations.

Results: 712 patients met the study criteria, 95 (13.3%) with completely normal endoscopic evaluation, 183 (25.7%) with histopathologic colitis, and 434 (60.9%) with gross endoscopic inflammation. Patients with normal initial endoscopic findings had less severe diarrhea at presentation with lower baseline calprotectin levels (p< 0.05) than those with any inflammatory findings. On multivariate regression controlling for diarrhea grade, we found that these patients were less likely to need selective immunosuppressive therapy (SIT) or IV steroids (p< 0.05) but were more likely to be re-hospitalized for colitis than those with inflammatory findings (p< 0.05). Macroscopic colitis often presented with a higher severity of diarrhea and colitis than histopathologic inflammation only (p< 0.05), and these patients were more likely to require SIT and hospitalization for their colitis, even after controlling for diarrhea and colitis grade (p< 0.05).

Discussion: This is the largest study to date reporting the initial patterns of endoscopic findings among patients with immune-mediated colitis. Patients with normal initial findings may require less aggressive treatment but may need closer monitoring to prevent progression of their colitis. Patients with microscopic colitis typically have a milder disease course than those with macroscopic inflammation. Future studies are needed to further characterize colitis endoscopic subtypes.


Disclosures:


Malek Shatila, MD¹, Andres Rivera, MD², Kian Abdul-Baki, DO³, Linfeng Lu, MD², Kei Takigawa, MD², Carolina Colli Cruz, MD⁴, Raakhi Menon, DO³, Elliot Axel. Baerman, MD², Andrew Sullivan, MD⁵, Tanvi Gupta, MD⁶, Hamza Salim, MD³, Varun Vemulapalli, MD⁶, Irene J. Lee, MD², Ayesha Khan, DO³, Cristina M. Natha, MD⁶, Krishnavathana Varatharajalu, MD¹, Garrett T. Coleman, ⁷, Dan Zhao, MD⁸, Anusha Thomas, MD¹, Yinghong Wang, MD, PhD⁸. P2612 - Initial Endoscopic Presentations of Immune Checkpoint Inhibitor Colitis and Their Differential Disease Outcomes, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.