Abstract
INTRODUCTION: The use of immune checkpoint inhibitors (ICI), such as Cemiplimab, has become prevalent in oncology, providing significant anti-tumor effects. However, these agents can induce severe gastrointestinal inflammation, which may be potentially life-threatening. This case report details an instance of Cemiplimab-induced colitis resulting in hypovolemic shock in a patient with cutaneous squamous cell carcinoma (cSCC). CASE PRESENTATION: An 83-year-old male veteran with a complex history of scalp squamous cell carcinoma, treated initially with excision and radiation, experienced recurrence necessitating Cemiplimab therapy. One year post-initiation, the patient presented with severe diarrhea, leading to hypovolemic shock and acute renal failure. Initial tests ruled out infectious causes. Endoscopic evaluation revealed inflammatory mucosal changes in the sigmoid colon, and histopathology confirmed active colitis. The patient responded well to high-dose prednisone, with rapid improvement in symptoms, leading to a transfer to a lower level of care. CONCLUSION: Cemiplimab, approved for advanced cSCC, fulfills a crucial therapeutic need but is associated with immune-related adverse events, including severe colitis. Management of such cases requires early endoscopy and corticosteroid therapy, which can significantly improve outcomes. This report underscores the importance of vigilant monitoring for gastrointestinal symptoms in patients undergoing ICI therapy and prompt intervention to mitigate severe complications.