Long-Term Efficacy and Safety of Multi-Matrix Mesalazine Maintenance Therapy in Pediatric Patients with Ulcerative Colitis.

Purpose: This study aimed to evaluate the efficacy and safety of multi-matrix mesalazine in pediatric patients with ulcerative colitis (UC) in remission. Methods: A multicenter, open-label, uncontrolled study was conducted in Japan, in which multi-matrix mesalazine 40 mg/kg was administered orally once daily for 48 weeks to 23 patients with UC in remission, aged <17 years. The primary endpoint was the nonoccurrence of rectal bleeding based on the Ulcerative Colitis Disease Activity Index (UC-DAI) score. Results: The percentage of patients without rectal bleeding, based on the UC-DAI score in the full analysis set, was 73.9% (two-sided 95% confidence interval [CI]: 51.6%, 89.8%; n=17/23). The lower limit of the two-sided 95% CI exceeded the predetermined threshold of 50%, derived from placebo group data in previous clinical studies involving adult patients with UC. The incidence of adverse events (AEs) and study drug-related AEs was 87.0% (n=20/23) and 13.0% (n=3/23), respectively. No deaths were reported. None of the study drug-related AEs were severe or serious, nor did they lead to discontinuation of the study drug. Conclusion: This study demonstrated the long-term efficacy of multi-matrix mesalazine in pediatric patients with UC in remission in Japan. No noteworthy safety concerns beyond those known to be associated with mesalazine were observed.