Clinical and endosonographic effect of ciprofloxacin on the treatment of perianal fistulae in Crohn's disease with infliximab: A double-blind placebo-controlled study

Background: Ciprofloxacin is effective in perianal Crohn's disease but after treatment discontinuation symptoms reoccur. Infliximab is effective but requires maintenance therapy. Aim: To evaluate the effect of combined ciprofloxacin and infliximab in perianal Crohn's disease. Methods: A double-blind placebo-controlled study was conducted. Patients were randomly assigned to receive 500-mg ciprofloxacin twice daily or a placebo for 12 weeks. All patients received 5-mg/kg infliximab in week 6, 8 and 12 and were followed for 18 weeks. Primary end-point was clinical response, defined as a 50% or greater reduction from baseline in the number of draining fistulae. Secondary end-points were the change in Perianal Disease Activity Index and hydrogen peroxide enhanced three-dimensional endoanal ultrasonography findings. Analysis was by intention-to-treat. Results: Twenty-four patients were included but two discontinued treatment. At week 18, response was 73% (eight of 11) in the ciprofloxacin group and 39% (five of 13) in the placebo group (P = 0.12). Using logistic regression analysis patients treated with ciprofloxacin tended to respond better (OR = 2.37, CI: 0.94-5.98, P = 0.07). The Perianal Disease Activity Index score only improved (P = 0.008) in the ciprofloxacin group. Three-dimensional endoanal ultrasonography improved in three patients with a clinical response. Conclusions: A combination of ciprofloxacin and infliximab tended to be more effective than infliximab alone.