Maintenance treatment of ulcerative proctitis with mesalazine suppositories: a double-blind placebo-controlled trial

Objectives: A multicenter double-blind placebo-controlled clinical study was conducted to evaluate the efficacy and tolerability of two different therapeutic schedules of mesalazine suppositories in patients with ulcerative proctitis. Methods: From 1990 to 1993, 111 patients with ulcerative proctisis in remission, limited to the rectum (≤ 15 cm from anus), were enrolled. After obtaining informed consent, patients were randomized to three treatment groups: 500 mg mesalazine b.i.d. (36 patients), 500 mg mesalazine u.i.d. (40 patients), and placebo (35 patients). The treatment lasted 1 yr. Follow-up consisted of periodic clinical, endoscopic, and histological assessments. An endoscopic score > 1 according to the Baron scale defined relapse occurence. The three groups were homogeneous as regards main demographic, diagnostic, and prognostic features. Results: The cumulative relapse rates at 12 months were 10% (95% confidence interval [CI]: 0–21) in the mesalazine b.i.d. group, 32% (95% CI: 16–49) in the mesalazine u.i.d. group, and 47% (95% CI: 29–65) in the placebo group. The comparison between the mesalazine b.i.d. group and the mesalazine u.i.d. group cumulative relapse rates gave a p value of 0.0334, whereas the corresponding comparison between the mesalazine b.i.d. group and the placebo group gave a p value of 0.007 (log-rank test). The dose-response relationship was statistically significant (p = 0.008 by Cox analysis). Two patients in the mesalazine b.i.d. group, two patients in the mesalazine u.i.d. group, and one patient in the placebo group withdrew from the study due to nonserious adverse events; four, three, and four patients per group, respectively, dropped out because of poor compliance. Two patients in the mesalazine u.i.d. group and two in the placebo group were lost to follow-up. Conclusions: The results of this study confirm the therapeutic efficacy of mesalazine suppositories in the maintenance treatment of ulcerative proctitis. According to our experience the most effective therapeutic schedule is 500 mg mesalazine b.i.d.