Systematic review: the potential influence of mesalazine formulation on maintenance of remission in Crohn's disease.

AIM: To evaluate the effectiveness of pH 6-/pH 7-dependent and controlled-release mesalazines in maintaining medically and surgically induced Crohn's disease remission. METHODS: A systematic search identified 13 randomized controlled trials (RCTs). The rate of symptomatic relapse (Crohn's disease activity index >150, or an increase in baseline by at least 60-100 points) was extracted from each randomized controlled trial. Pooled odds ratios (OR), the number needed to treat (NNT), and percentage therapeutic benefit (absolute risk reduction) were calculated. RESULTS: Treatment with pH 7-dependent mesalazine significantly reduced the risk of relapse in patients with either surgically [OR 0.28; 95% confidence interval (CI) 0.12-0.65; P = 0.0032] or medically induced remission (OR 0.38; 95% CI 0.17-0.85; P = 0.0113). However, treatment with controlled-release mesalazine and pH 6-dependent mesalazine failed to show any significant advantage over placebo. The NNT to maintain surgically or medically induced remission was lowest for pH 7-dependent mesalazine (NNT = 4 and 5, respectively; NNT = 15 and 16 for controlled-release mesalazine and NNT = 11 and 23 for pH 6-dependent mesalazine). Therapeutic benefit was highest for pH 7-dependent mesalazine (surgical = 30.6%, medical = 22.8%). This compared with 6.9% (surgical) and 6.4% (medical) for controlled-release mesalazine, and 9.8% and 4.4%, respectively, for pH 6-dependent mesalazine. CONCLUSION: Further trials of pH 7-dependent mesalazine formulations are warranted in the maintenance of remission in Crohn's disease.