Severe terminal ileitis induced by single-agent nivolumab administered every four weeks

Introduction: Use of immune checkpoint inhibitors has expanded to a variety of malignancies including hepatocellular carcinoma, where nivolumab and pembrolizumab have shown durable responses in approximately a sixth of patients.

Case report: We report herein a patient with metastatic hepatocellular carcinoma who achieved a durable response to the second-line agent nivolumab administered intravenous 240 mg every two weeks. After 18 months of therapy, nivolumab schedule was changed to intravenous 480 mg every four weeks, per patient's request and for convenience of administration. Four days after this change, the patient developed severe terminal ileitis.Management and outcome: This condition was managed in hospital with intravenous steroids. The patient improved clinically and was discharged on an oral steroid taper. A month later, nivolumab was reinstated at 200 mg intravenous infusions every two weeks, without any re-occurrence of terminal ileitis to date as of six months after the probable drug reaction.

Discussion: To our knowledge, this is the first report of terminal ileitis with nivolumab administered every four weeks. As postmarketing evaluation of nivolumab continues, similar side effects may be observed. Prompt diagnosis and steroid therapy in these cases are imperative to ensure a favorable outcome. Resuming immunotherapy once the adverse event has resolved appears to be a safe option.