Late-Onset Inflammatory Bowel Disease-Like Syndrome after Ipilimumab Therapy: A Case Report

Antitumor immunotherapy has become a major player in cancer therapy. Ipilimumab is a humanized monoclonal antibody against the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), an important downregulator of T-cell activation. Ipilimumab has demonstrated tumor regression and improvement in overall survival in patients with metastatic melanoma. Unfortunately, immune activation induced by this drug has been associated with several immune-mediated adverse effects, namely diarrhea and colitis.

We report the case of a 71-year-old male patient diagnosed with BRAF wild-type metastatic melanoma treated with three cycles of ipilimumab, after which he developed grade 3 enteritis. The patient improved on treatment with steroids, and ipilimumab was permanently discontinued at this point. Three years later, the patient's diarrhea returned and colonoscopy revealed active chronic colitis with ulceration resembling inflammatory bowel disease. He was started on Asacol (mesalamine). The patient did not report extraintestinal symptoms typically associated with inflammatory bowel disease, nor did he have a personal or family history of bowel disorders. Moreover, his presentation was not typical of inflammatory bowel disease in the elderly.

Our findings suggest a link between ipilimumab-induced grade 3 enteritis and late-onset inflammatory bowel disease-like syndrome. To our knowledge, the case is the first in the literature to report late-onset inflammatory bowel disease-like syndrome years after discontinuation of ipilimumab treatment.