Randomised Clinical Trial: Once- Vs. Twice-daily Prolonged-release Mesalazine for Active Ulcerative Colitis

Background: Aminosalicylates are first-choice treatment for mild-to-moderately active ulcerative colitis (UC); however, multi-dosing regimens are inconvenient.

Aim: To compare the efficacy and safety of once- (OD) vs. twice- (BD) daily prolonged-release mesalazine (Pentasa, Ferring, Saint-Prex, Switzerland) for active mild-to-moderate UC in a non-inferiority study.

Methods: Eligible patients (n = 206) were randomised to 8 weeks of mesalazine (4 g/day), either OD with two sachets of 2 g mesalazine granules in the morning (n = 102) or BD with one 2 g sachet in the morning and one in the evening (n = 104). Patients also received 4 weeks of mesalazine enema 1 g/day. Disease activity was assessed at randomisation, weeks 4, 8 and 12 using the UC Disease Activity Index (UC-DAI). Clinical and endoscopic remission (primary endpoint) was assessed after 8 weeks. Patients recorded stool frequency and rectal bleeding in a daily diary.

Results: The primary endpoint, non-inferiority in clinical and endoscopic remission with OD vs. BD mesalazine at 8 weeks, was met (intent-to-treat population: 52.1% vs. 41.8%, respectively, 95% confidence interval -3.4, 24.1; P = 0.14). Improvement of UC-DAI score (92% vs. 79%; P = 0.01) and mucosal healing (87.5% vs. 71.1%; P = 0.007) were significantly better, time to remission significantly shorter (26 vs. 28 days; P = 0.04) and safety similar with OD vs. BD dosing.

Conclusions: When combined with mesalazine enema, prolonged-release mesalazine once-daily 4 g is as effective and well tolerated as 2 g twice-daily for inducing remission in patients with mild-to-moderately active ulcerative colitis (Clinicaltrials.gov: NCT00737789).