The Efficacy of Early Treatment in Immune Checkpoint Inhibitor-Related Colitis: Clinical Outcomes in a Retrospective Case Series

BACKGROUND: New immunotherapy using immune checkpoint inhibitors plays a critical role in cancer treatment. Immune checkpoint inhibitor-related colitis (irAE-colitis) occurs in approximately 1–20% of cancer patients treated with immune checkpoint inhibitors. There are limited data on the outcomes of optimal treatment in patients with irAE-colitis. The aim of this report was to clarify treatment outcomes for patients with irAE-colitis in our facilities.

METHODS: Of 676 patients who received immune checkpoint inhibitors at our hospital and related facilities, nine patients who developed irAE-colitis were included. We defined effectiveness as follows: a decrease of 3 points or more in a Mayo endoscopic sub-score, 0 or 1 points in a rectal bleeding score and 2 points or more in a Mayo clinical score.

RESULTS: The male-to-female ratio was five to four. There were five cases of lung cancer, one case of renal cancer, one of head and neck cancer, one of melanoma, and one of gastric cancer. The immune checkpoint inhibitors pembrolizumab and nivolumab, which are anti-PD-1 antibodies, were used in six and three cases, respectively. The drugs used after onset are as follows. One case was mesalazine, six were steroids, one was infliximab, and one was cyclosporine. The effective rate of steroids was 84% (5/6 cases), of which two cases relapsed during steroid tapering. However, both cases improved with steroid re-administration. For one case where steroids were ineffective, we used infliximab. Although the patient’s condition improved temporarily, we encountered secondary failure and changed to cyclosporine, which was effective. One case died before treatment intervention due to severe diarrhea. Immune checkpoint inhibitors were discontinued in all cases. At the time of writing, six patients are still alive after improvement of abdominal symptoms.

CONCLUSION(S): Steroid therapy was quite effective for the treatment of irAE-colitis, although early relapse occurred in some cases. Prospective studies are required to define the optimal management of irAE-colitis in order to maintain positive long-term outcomes.