Randomised clinical trial: evaluation of the efficacy of mesalazine (mesalamine) suppositories in patients with ulcerative colitis and active rectal inflammation -- a placebo-controlled study.

BACKGROUND: Mesalazine suppositories are recommended and widely used as the standard therapy in induction and maintenance of remission for proctitis.

AIM: To evaluate the efficacy of mesalazine suppositories in patients with ulcerative colitis (UC) and rectal inflammation; and in patient groups categorised by the extent of lesions.

METHODS: This study was a phase III multicentre, randomised, double-blind, placebo-controlled, parallel-group study. Mild-to-moderate UC patients with rectal inflammation were randomly assigned either a 1 g mesalazine or placebo suppository. The suppository was administered in the rectum once daily for 4 weeks. The primary efficacy end point was the rate of endoscopic remission (mucosal score of 0 or 1) after 4 weeks.

RESULTS: The endoscopic remission rates after 4 weeks in the mesalazine and placebo suppository groups were 81.5% and 29.7%, respectively, and the superiority of mesalazine to placebo was confirmed (P < 0.0001, chi-squared test). For proctitis, the endoscopic remission rates after 4 weeks were 83.8% and 36.1% in the mesalazine and placebo suppository groups, respectively, and the corresponding rates for all other types of UC were 78.6% and 21.4%, respectively. The superiority of mesalazine to placebo was confirmed in both subgroups (P < 0.0001, Fisher's exact test). The percentage of patients without bleeding was significantly higher in the mesalazine group than the placebo group from Day 3 of treatment (P = 0.0001, Fisher's exact test).

CONCLUSIONS: The effectiveness of mesalazine suppositories in all types of UC patients with rectal inflammation was confirmed for the first time in a double-blind, placebo-controlled, parallel-group study (JapicCTI- 111421).