Predictors of response to infliximab in patients with fistulizing Crohn's disease.

Objective: To evaluate the efficacy and toxicity of infliximab for the treatment of fistulizing Crohn's disease.
Methods: Consecutive patients with fistulizing Crohn's disease receiving infliximab were prospectively enrolled. Partial response was defined as a reduction of 50% or more from base-line in the number of draining fistulae. Complete response was defined as the closure of all fistulae. The influence of different variables on the efficacy of infliximab was evaluated.
Results: 108 patients were included. The disease was inflammatory plus fistulizing in 18% and only fistulizing in 82%. After the third infusion of infliximab the response was partial in 26% and complete in 57%. Response (%) rates (partial/complete) depending on fistula location were: enterocutaneous (25/68%), perianal (35/60%), rectovaginal (36/64%), and enterovesical (20/40%). None of the studied variables (including concomitant immunosuppressive therapy) correlated with efficacy of infliximab in the multivariate analysis. Incidence of adverse effects (21%) depending on the dose of infliximab was: first dose (5.6%), second (7.4%), and third (11.1%).
Conclusions: Infliximab is an efficacious treatment for fistulizing Crohn's disease. Partial response was achieved in approximately one third of the patients, and complete response in more than half. No studied variable was predictive of response. Adverse effects were relatively infrequent and mild.