P1370 - Immune Checkpoint Inhibitor-Induced Ulcerative Gastritis

Olufemi E. Osikoya, MD¹, Gregory Brennan, MD^2
1Medical City Arlington, Arlington, TX; ²Texas Digestive Disease Consultants, Mansfield, TX

Introduction: Pembrolizumab is an immune checkpoint inhibitor that blocks programmed death-1 (PD-1). Immune related adverse events (irAE) developed as a consequence of impaired self tolerance after loss of T-cell inhibition. irAEs frequently affects the gastrointestinal tract, the most common being diarrhea and colitis. Upper GI tract irAE are much rarer, and there are very few reports of isolated gastric involvement as presented in this case.

Case Description/Methods: This is a case of a 71-year-old man with a past medical history of stage IV non-small cell lung cancer who was referred to GI clinic for epigastric abdominal pain. The patient was previously treated with pembrolizumab 6 months prior to presentation. The patient initially did well on treatment but developed epigastric abdominal pain approximately 5 months after starting pembrolizumab. EGD was performed which revealed isolated severe diffuse ulcerations throughout the entire gastric mucosa. Pathology revealed chronic active severe gastritis with surface ulceration. CMV stains were negative. The patient was initially started on 80 mg of prednisone daily and omeprazole 40 mg twice daily. The patient's symptoms resolved, and prednisone was tapered down to 10 mg daily. Repeat EGD was performed 4 months later which showed complete mucosal healing of the stomach.

Discussion: Here we present a case of isolated pembrolizumab induced ulcerative gastritis. Gastroenterologist are encountering irAE more frequently as immune checkpoint inhibitors are becoming standard of care. Isolated upper GI tract involvement remains rare. Early recognition is key to guiding treatment. In this case, the patient responded to a combination of prednisone and PPI. Further studies investigating the prevalence of isolated upper GI irAEs and treatments are warranted.



Disclosures:


Olufemi E. Osikoya, MD¹, Gregory Brennan, MD². P1370 - Immune Checkpoint Inhibitor-Induced Ulcerative Gastritis, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.