Topical tacrolimus in the treatment of perianal Crohn's disease: exploratory randomized controlled trial

The aim of this study is to evaluate the efficacy of topical tacrolimus in treating perianal Crohn's disease.

Nineteen patients, stratified into 7 with ulcerating, and 12 with fistulizing, perianal Crohn's disease were randomized to topical tacrolimus 1 mg/g (1 g ointment twice a day [bid]) or placebo for 12 weeks. Sixteen patients had been on, or were currently taking, azathioprine/6-MP, and 6 had received infliximab. The primary outcome in ulcerating disease was global improvement in perianal/anal lesions, as assessed by the attending physician; for fistulas, it was reduction of > or =50% of actively draining fistulas on 2 consecutive visits. Blood tacrolimus levels and adverse events were assessed.

Three of 4 patients treated with topical tacrolimus for ulcerating disease improved compared with none of 3 in the placebo group. Complete healing was not achieved. In fistulizing disease, topical tacrolimus was not beneficial. Two tacrolimus-treated patients developed perianal abscesses, 1 after improvement in fistula drainage. Adverse events were otherwise infrequent and mild. Whole blood tacrolimus levels were detectable in only 2 patients and were low.

These preliminary data suggest that topical tacrolimus is effective and safe in the treatment of perianal or anal ulcerating Crohn's disease. This therapy is unlikely to be beneficial in fistulizing perianal Crohn's disease, although a larger study is required to confirm this.