Nivolumab shows promising efficacy against metastatic melanoma. However, immune-related adverse events are of great concern. We herein report a case of persistent colitis that developed during nivolumab monotherapy and nivolumab readministration. An 82-year-old Japanese woman with recurrent melanoma developed Grade 3 colitis after 6 cycles of nivolumab. She was treated with corticosteroid for 28 days. Follow-up by computed tomography and colonoscopy after corticosteroid treatment revealed persistent pancolitis. Her symptoms ameliorated spontaneously in two months. Given the amelioration, nivolumab was restarted and resulted in the maintenance of stable disease for 21 months without recurrence of colitis. Even in cases of persistent colitis over several months, nivolumab readministration should be considered.
Keywords: PD-1 inhibitor; colitis; immune-related adverse event; melanoma; readministration.