Colectomy Incidence Rates in Five-Year Data From the Observational Postmarketing Ulcerative Colitis Study of Originator Infliximab

Background: This analysis of the Observational Postmarketing Ulcerative Colitis Study examined incidence rates of colectomy in patients with ulcerative colitis who received originator infliximab (IFX) or conventional therapies (ConvRx) as per their treating physician.

Methods: Cox proportional hazards models compared time to colectomy for both treatment groups. A secondary analysis examined colectomy incidence rates based on IFX exposure timing (defined by a 90-day window after the last IFX dose date).

Results: Of 2239 patients with data, 1059 enrolled in IFX and 1180 enrolled in ConvRx (including 296 patients who switched to IFX). Patients in the IFX group had more severe disease at baseline vs the ConvRx group (percentage with baseline partial Mayo score 7-9: 46.0% vs 30.5%, respectively). During 5 years of follow-up, 271 patients (12.1% of enrolled patients) had colectomy. Enrollment in the IFX group was associated with a higher risk of colectomy (hazard ratio = 3.12; 95% confidence interval, 2.25-4.34; P < 0.001) compared with enrollment in the ConvRx group. A total of 174 colectomies occurred in the IFX group, but 97 of these colectomies occurred ≥90 days after the last IFX dose date.

Conclusions: Colectomy was reported at a higher rate in the IFX group than in the ConvRx group, although patients in the IFX group had more severe disease at baseline and most of the colectomies occurred after patients had been off of IFX for ≥90 days.