Background: Crohn’s disease has been linked to adherent strains of E.coli. They exist in the lumen, as a biofilm or as intracellular bacteria. An ideal antibiotic would be effective in all compartments, which is not the case for quinalones and metronidazole. Azithromycin is active in all three compartments and induces apoptosis of T-cells. We evaluated the efficacy of azithromycin for induction of remission.
Methods: This was a single blinded multinational randomized controlled trial. Patients with 10 ≤ PCDAI ≤ 40 were randomized to azithromycin and metronidazole (Group 1) or to metronidazole alone (Group 2) for 8 weeks. Failures in group 2 could receive open label azithromycin. The primary endpoint was ITT response or remission (PCDAI ≤10) at week 8.
Results: 73 patients (mean age 13.82 ± 3.10 SD) were enrolled, 35 ( Group 1) and 38 ( Group 2). The response rates were 62% (22/35) in group 1 and 44% (17/38) in Group 2 (p=0.16).Remission rates were 62% in Group 1, and 42% in Group 2, (p=0.10). Among 11 patients in the open label group failing therapy from Group 2, treatment with azithromycin led to remission in 9/11(81.8%).
Conclusions: Adding azithromycin to metronidazole led to superior remission rates and induced remission in metronidazole failures; however this did not reach statistical significance. Antibiotic therapy in Crohn`s disease seems to act as an all or none response, since there were no differences between remission rates and response rates, suggesting that sensitivity to antibiotics and not the immunomodulatory properties might be the important predictor of response.
