Assessing the Clinical and Endoscopic Efficacy of Extended Treatment Duration with Different Doses of Mesalazine for Mild-to-Moderate Ulcerative Colitis beyond 8 Weeks of Induction.

Introduction: High-strength mesalazine formulations play an important role in providing a convenient option to increase the dose in ulcerative colitis (UC) patients and therefore avoiding the switch to another therapeutic class. Higher doses of mesalazine may be required during periods of remission in order to prevent relapse.

Aim: The aim of the study was to investigate clinical outcomes of three mesalazine maintenance doses adapted for post induction response.

Methods: In this post hoc analysis, 675 UC patients entered an open-label extension study for a total of 38 weeks (including 8-12 week induction period with 3.2 g/day mesalazine). After the induction period, they were separated into three groups: remitters (in clinical and endoscopic remission), responders (decrease in Partial Mayo Clinic Score of ≥2 points and ≥30% from week 0), and nonresponders (failed to achieve endoscopic or clinical response at week 8) and received 1.6 g/day, 3.2 g/day, or 4.8 g/day of mesalazine (using a new 1,600 mg mesalazine tablet), respectively.

Results: 133/202 (65.8%), 108/274 (39.4%), and 59/199 (29.6%) patients achieved clinical and endoscopic remission at week 38 with 1.6 g/day, 3.2 g/day, and 4.8 g/day, respectively. At week 38, 142/202 (70.3%), 93/274 (33.9%), and 61/199 (30.7%) patients achieved clinical remission (stool score of 0 and rectal bleeding score of 0) with 1.6 g/day, 3.2 g/day, and 4.8 g/day, respectively.

Conclusions: Patients partially responding or not responding to an initial induction dose of 3.2 g/day mesalazine could benefit from an extended treatment period at the same dose, or an increase to 4.8 g/day in an attempt to achieve combined clinical and endoscopic remission.