Topical beclometasone dipropionate in the management of immune checkpoint inhibitor-induced microscopic colitis

Immune checkpoint inhibitors (ICPis) have revolutionised survival outcomes for cancer patients by bolstering anti-tumour immunity. However, immune activation also occurs in non-cancer tissue, and a significant proportion of patients develop immune-mediated colitis, which can be fatal if not promptly recognised and managed. Diagnosis is often made by inflammation observed during lower gastrointestinal endoscopy. Little is known about microscopic inflammation (histological findings of inflammation in the absence of overt mucosal injury). Management strategies beyond the use of systemic corticosteroids, which incur a high burden of deleterious side effects, have not been extensively explored. We describe the cases of two cancer patients with ICPi-induced colitis who had isolated histoloigical features of colitis in the absence of macroscopic disease. Sustained clinical and histological remission was induced with the topical steroid preparation, beclometasone dipropionate (Clipper), with no adverse effects.