Open label trial of oral clarithromycin in active Crohn's disease

Background: Crohn's disease seems likely to be due in some way to bacteria. Clarithromycin is a broad spectrum macrolide antibiotic with good penetrat ion into macrophages and may be effective in eradicating the organisms that are presumed to be at the centre of the granulomatous reaction in Crohn's disease. Methods: Twenty-five patients with active Crohn's disease were treated with oral clarithromycin 250 mg b.d. in an open label study. Treatment was for an initial 4-week period, continued to 12 weeks in patients who had shown a partial or complete response. The patients had a median age of 30 years (r ange 17-72), and disease duration of 5 years (range 2 months-28 years); 14 had ileocolonic, four small bowel, seven colonic disease and 10 had previou s resections. Twenty patients were receiving a 5-ASA preparation, 15 cortic osteroids (prednisolone median dose 10 mg range 2-30 mg) and nine azathiopr ine. All patients receiving corticosteroids or azathioprine had been on unc hanged treatment for at least 12 weeks. Results: Median pre-treatment Harvey Bradshaw index (HBI) was 9 (range 5-16 ) and median serum C-reactive protein was 21.5 mg/L (range < 5-117). By 4 w eeks the median HBI had decreased to 5 (range 0-18) (P < 0.001) and median CRP to 17 mg/L (range < 5-157) (P=0.16). Sixteen patients (64%) had at leas t a 3 point fall in HBI and remission (defined as a HBI less than or equal to 4) was achieved in 12 patients (48%). By 12 weeks median HBI was 5 (rang e 0-18) (P < 0.001) and median CRP was 14.5 mg/L (range < 5-157) (P=0.05). Eleven of the 25 patients studied continued on oral clarithromycin after 12 weeks for a median of 28 weeks (range 20-60). Eight (73%) remained in remi ssion on treatment. When treatment with clarithromycin was stopped three re mained in remission and five relapsed after a median of 5 months (range 4-9 ). Two patients withdrew due to non-serious side-effects. Treatment was wel l tolerated in the remaining patients. Conclusion: This open label study has shown an impressive response to clari thromycin in a group of patients with active Crohn's disease, many of whom had been resistant to other therapy. A formal randomized controlled trial o f clarithromycin in active Crohn's disease is needed.