Efficacy of anti-TNF therapies in refractory severe microscopic colitis.

BACKGROUND: Refractory microscopic colitis is a rare condition with an unknown rate of occurrence. The efficacy of anti-tumor necrosis factor (TNF) therapy for microscopic colitis has never been reported. Aims 1) To report the frequency of refractory microscopic colitis in the database of the participant hospitals. 2) To describe the therapeutic response to anti-TNF therapy among the refractory cases.

METHODS: Patients with a histological diagnosis of collagenous colitis and lymphocytic colitis were identified through the Department of Pathology database and the IBD practice database. Patients refractory to medical treatment and with severe symptoms were offered anti-TNF therapy.

RESULTS: Five of 372 MC patients (1.3%; 95% CI, 0.6 to 3.1) presented with severe symptoms refractory to standard medical therapies. One patient was denied therapy from her insurance carrier. The other 4 received infliximab therapy. The response was excellent after one dose experiencing a 60-90% decrease in bowel movements. Three patients were switched to adalimumab (2 allergic reactions and 1 early loss of response to infliximab). Long-term clinical remission (more than 1 year) was achieved in three cases (2 with adalimumab and 1 with infliximab). One patient on adalimumab had an early loss of response and was referred for colectomy.

CONCLUSIONS: Microscopic colitis with severe symptoms refractory to standard medical therapy including immunosuppressives is uncommon. In this setting, anti-TNF therapies may be a good option to avoid colectomy.