Combination Therapy With Infliximab and Azathioprine Is Superior to Monotherapy With Either Agent in Ulcerative Colitis

Abstract

The comparative efficacy and safety of infliximab and azathioprine therapy alone or in combination for ulcerative colitis (UC) have not been evaluated previously. This randomized, double-blind trial evaluated the efficacy and safety of 16 weeks of treatment with infliximab monotherapy, azathioprine monotherapy, or the 2 drugs combined in tumor necrosis factor-a antagonist-naive adults with moderate to severe UC. Patients were assigned randomly to receive intravenous infusions of infliximab 5 mg/kg at weeks 0, 2, 6, and 14 plus daily oral placebo capsules; oral azathioprine 2.5 mg/kg daily plus placebo infusions on the infliximab schedule; or combination therapy with the 2 drugs. Corticosteroid-free clinical remission (primary end point, week 16) was evaluated at weeks 8 and 16. The study was terminated before the enrollment target was reached. A total of 239 patients were included in efficacy analyses. Baseline characteristics were similar between treatment groups. Corticosteroid-free remission at week 16 was achieved by 39.7% (31 of 78) of patients receiving infliximab/azathioprine,compared with 22.1% (17 of 77) receiving infliximab alone(P =.017) and 23.7% (18 of 76) receiving azathioprine alone(P =.032). Mucosal healing at week 16 occurred in 62.8% (49 of 78) of patients receiving infliximab/azathioprine, compared with 54.6% (42 of 77) receiving infliximab (P = .295) and 36.8% (28 of 76) receiving azathioprine (P =.001). Serious infections occurred in 2 patients (1 patient receiving infliximab,and 1 patient receiving azathioprine). Anti–tumor necrosis factor-a–naive patients with moderate to severe UC treated with infliximab plus azathioprine were more likely to achieve corticosteroid-free remission at 16 weeks than those receiving either monotherapy. Combination therapy led to significantly better mucosal healing than azathioprine monotherapy. ClinicalTrials.gov number, NCT00537316.