Combining infliximab with 6-mercaptopurine/azathioprine for fistula therapy in Crohn's disease.

OBJECTIVES: Fistulas occur in about one third of patients with Crohn's disease and rarely heal spontaneously. Conventional medical and surgical therapy often fails. The anti-TNF-alpha antibody infliximab offers a novel therapeutic option. By this approach, closure of fistulas was reported in 45% of cases. However, after discontinuation of therapy, most fistulas recurred. Azathioprine and 6-mercaptopurine (6-MP) are effective drugs in Crohn's disease and lead to closure of fistulas in 30-40% of cases. Thus, the aim of this study was to evaluate the combination of infliximab with 6-mercaptopurine/azathioprine as therapy for fistulas in patients with Crohn's disease.

METHODS: A total of 16 patients (mean age 37 yr) with Crohn's fistulas resistant to conventional measures were treated with a combination of three or four infusions of infliximab and long term 6-MP/azathioprine. In all, 13 patients had perianal fistulas, two had abdominal fistulas, and one patient had both perianal and recto-vaginal fistulas. Therapy success was defined as complete closure of fistulas for a minimum observation period of 6 months after fistula closure.

RESULTS: In 12 (75%) of the 16 patients, we observed complete closure of the fistulas that persisted for >6 months (median follow-up 10 months, range 6-11 months). The median time to complete closure of fistulas was 14 days (range 2-36 days). In four patients, therapy success was not achieved.

CONCLUSION: Our pilot study reveals that concomitant and long term 6-MP/azathioprine therapy could prolong the effect of an initial infliximab therapy on fistula closure in patients with Crohn's disease. These data prompt larger controlled trials.