A Multicenter, Randomized Study to Evaluate the Efficacy and Safety of Mesalamine Suppositories 1 g at Bedtime and 500 mg Twice Daily in Patients with Active Mild-to-Moderate Ulcerative Proctitis

BACKGROUND: Ulcerative proctitis (UP) is a prevalent condition associated with increased morbidity and mortality. Topical mesalamine (5-aminosalicylic acid [5-ASA]) inhibits inflammatory processes in UP. METHODS: We evaluated effects of mesalamine 1-g suppository administered QHS compared with 500-mg suppository administered BID on UP activity (e.g., disease extension/mucosal appearance), remission, onset of response, safety and compliance in 97 patients with UP. A 6-week, randomized, multicenter, parallel-group, noninferiority study was conducted (and published) with Disease Activity Index (DAI) at week 6 as the primary efficacy variable and individual components of DAI at week 6 (i.e., stool frequency, rectal bleeding, mucosal appearance, global assessment) as secondary variables. Unreported outcomes were remission (DAI < 3 at weeks 3 and 6), disease extension, and complete response to treatment (DAI = 0; post-hoc, exploratory analysis). RESULTS: DAI values after 6 weeks were significantly reduced (±SD) from 6.6 ± 1.5 to 1.6 ± 2.3 (500-mg BID); and from 6.1 ± 1.5 to 1.3 ± 2.2 (1-g QHS). Mucosal appearance significantly improved from baseline after 3 and 6 weeks of treatment from 1.8 ± 0.5 to 0.8 ± 0.7 and 0.5 ± 0.7 (500-mg BID; P ≤ 0.0062) and from 1.7 ± 0.5 to 0.9 ± 0.5 and 0.4 ± 0.6 (1-g QHS; P ≤ 0.0001), respectively. Remission was comparable (78.3-86.1%); onset of response generally occurred within 3 weeks, and disease extension was reduced (>70%) after 6 weeks in both groups. Mesalamine was well tolerated. Compliance was >96%. CONCLUSIONS: Mesalamine 500-mg BID and 1-g QHS suppositories are safe and effective for patients with UP. Most patients reported significant improvement within 3 weeks and UP remission and reduced disease extension after 6 weeks of treatment. Validity of QHS administration was confirmed.