Mesalamine once daily is more effective than twice daily in patients with quiescent ulcerative colitis.

Background & Aims: Oral mesalamine (5-aminosalicylate) is the current standard of care for mild-to-moderate ulcerative colitis. We investigated the efficacy and safety of once daily administration of prolonged-release mesalamine granules in maintenance of remission in patients with quiescent ulcerative colitis, compared with the well established twice daily dosing regimen.

Methods: In this multicenter, randomized, single blind, noninferiority trial, 362 patients with quiescent ulcerative colitis were randomly assigned (1:1) to groups that were given oral mesalamine 2 g, once daily, or 1 g, twice daily, for 12 months. The primary objective was to compare remission rates at 1 year, based on the ulcerative colitis disease activity index score, using Kaplan-Meier methodology.

Results: At 1 year, 70.9% of the group given 2 g mesalamine once daily remained in remission vs 58.9% of the group given 1 g mesalamine twice daily; this difference was statistically significant (P = .024), indicating the increased efficacy of once daily, compared with twice daily, dosing. Self-reported adherence to therapy, measured by visual analog scale score after 4, 8, and 12 months, was significantly greater in the group given 2 g mesalamine once daily, compared with twice daily, at all but 1 study visit (P < .05). Compliance measured by medication taken was not significantly different between the groups. The difference between the 2 groups in overall incidence of adverse events was not statistically significant (P = .23).

Conclusions: Patients with ulcerative colitis given prolonged-release oral mesalamine 2 g once daily had better remission rates, acceptability, and self-reported adherence to therapy compared with patients given oral mesalamine 1 g twice daily.