The noninferiority of pH-dependent release mesalamine (Asacol) once daily (QD) to 3 times daily (TID) administration was investigated.
This was a phase 3, multicenter, randomized, double-blind, parallel-group, active-control study, with dynamic and stochastic allocation using central registration. Patients with ulcerative colitis in remission (a bloody stool score of 0, and an ulcerative colitis disease activity index of ≤2), received the study drug (Asacol 2.4 g/d) for 48 weeks. The primary efficacy endpoint of the nonrecurrence rate was assessed on the full analysis set. The noninferiority margin was 10%.
Six hundred and four subjects were eligible and were allocated; 603 subjects received the study drug. The full analysis set comprised 602 subjects (QD: 301, TID: 301). Nonrecurrence rates were 88.4% in the QD and 89.6% in the TID. The difference between nonrecurrence rates was -1.3% (95% confidence interval: -6.2, 3.7), confirming noninferiority. No differences in the safety profile were observed between the two treatment groups. On post hoc analysis by integrating the QD and the TID, nonrecurrence rate with a mucosal appearance score of 0 at determination of eligibility was significantly higher than the score of 1. The mean compliance rates were 97.7% in the QD and 98.1% in the TID.
QD dosing with Asacol is as effective and safe as TID for maintenance of remission in patients with ulcerative colitis. Additionally, this study indicated that maintaining a good mucosal state is the key for longer maintenance of remission.