Open label trial of clarithromycin therapy in Japanese patients with Crohn's disease

The pathogenesis of Crohn's disease is unclear, but many studies suggest that luminal bacteria play an important role in chronic intestinal inflammation in patients with this condition. Clarithromycin is a macrolide antibiotic with immunomodulatory activity. The aim of this study was to evaluate the effect of clarithromycin therapy in Japanese patients with Crohn's disease.

Fourteen patients with active Crohn's disease (12 with ileocolonic, one with colonic, one with small bowel type) were treated with oral clarithromycin 200 mg twice daily for 4 weeks. Patients who showed a clinical response within 4 weeks continued the therapy for up to 24 weeks. Four patients also received azathioprine. Clinical activity was assessed with the Crohn's Disease Activity Index (CDAI) at entry and at 4, 12, and 24 weeks after starting clarithromycin.

The mean CDAI score at entry was 343.5. Within 4 weeks, eight (57.1%) of the 14 patients showed clinical improvement, and five (35.7%) of the eight patients achieved remission. All of those eight patients continued clarithromycin therapy after 4 weeks, and six (42.9%) were in clinical remission at 12 weeks. Of the 14 total patients, four (28.6%) continued clarithromycin for more than 24 weeks, and have remained in remission. Patients who received azathioprine concomitantly had a better response to clarithromycin therapy. No severe side-effects were observed during the study period.

This open label study showed encouraging results of clarithromycin therapy in Japanese patients with active Crohn's disease.