Long-term Combination Therapy with Infliximab Plus Azathioprine Predicts Sustained Steroid-free Clinical Benefit in Steroid-dependent Ulcerative Colitis

Background: Infliximab (IFX) has demonstrated effectiveness for inducing 12-month steroid-free clinical remission in patients with steroid-dependent ulcerative colitis (UC), but long-term data are lacking. The aim of the study was to describe the long-term outcome of IFX treatment in steroid-dependent UC and investigate if predictors of sustained clinical response and colectomy could be identified. Methods: Consecutive patients with steroid-dependent UC treated with IFX were studied. The coprimary prespecified outcomes were sustained clinical response in patients who achieved clinical remission or response after IFX induction and colectomy-free survival. Secondary analyses were addressed to look for predictors of sustained clinical response and colectomy. Results: After induction, 76% (96/126) of patients achieved clinical benefit. The median duration of follow-up on IFX maintenance therapy was 41.5 months (interquartile range, 26-45). Sixty-four percent (46/96) of patients had sustained clinical response at median follow-up. Colectomy-free survival was 77% at median follow-up. Combination therapy of IFX with thiopurines was an independent predictor of sustained clinical response (P < 0.0001; hazard ratio [HR], 3.98; 95% confidence interval [CI], 1.73-9.14). Independent predictors of colectomy were Mayo endoscopic subscore of 3 at baseline (P = 0.04; HR, 2.77; 95% CI, 1.09-7.05) and high C-reactive protein after induction (P = 0.001; HR, 5.65; 95% CI, 2.03-15.7). Thiopurine naive status (P = 0.025; HR, 0.34; 95% CI, 0.13-0.87) was protective from colectomy. Conclusions: Long-term IFX treatment is effective in inducing sustained clinical response in patients with steroid-dependent UC. Combination therapy is predictive of sustained clinical response in the long-term. Patients with more severe endoscopic lesions at baseline and high C-reactive protein after induction are at higher risk of colectomy. Conversely, thiopurine naive status is protective from colectomy.