Background: Mesalazine preparations are widely used to treat mild to moderately severe ulcerative colitis (UC). We compared once-daily administration of oral mesalazine in patients with quiescent UC with the established 3-times-daily prescription, assessing the efficacy and safety of each method in maintaining remission for 52 weeks.
Methods: This was a double-blind, double-dummy, randomized, multicenter noninferiority study in which 301 patients with quiescent UC were randomly assigned to treatment groups and administered prolonged-release oral mesalazine at doses of 1.5 to 2.25 g/d once daily (QD) or 3 times daily (TID) for 52 weeks. The primary endpoint was whether remission was maintained after 52 weeks of administration or until the time of discontinuation, as represented by the Ulcerative Colitis Disease Activity Index score.
Results: The proportion of patients still in remission after 52 weeks of administration was 79.4% in the QD group and 71.6% in the TID group. The between-group difference was 7.8% (2-tailed 95% confidence interval [CI]: −2.2% to 17.8%), and the noninferiority of QD administration to TID administration was verified with a noninferiority margin of −10%. In the safety analysis, the incidence of adverse events in each group was 72.4% for the QD group and 76.5% for the TID group, showing no statistically significant difference between the 2 groups (P = 0.4305).
Conclusions: This double-blind parallel-group comparison verified for the first time the noninferiority of QD administration of oral mesalazine 1.5 to 2.25 g/d to TID administration in terms of maintaining remission in patients with UC.