Similar pharmacokinetics of three dosing regimens comprising two oral delayed-release mesalamine formulations in healthy adult volunteers: Randomised, open-label, parallel-group study

Abstract

Aims: Mesalamine is the first-line therapy for treating mild-to-moderate ulcerative colitis. Multiple mesalamine formulations are available, with similar safety and efficacy profiles. Mesalamine is commonly administered as divided dosing, although once-daily dosing may provide benefits for patients. We evaluated the pharmacokinetics of three dosing regimens of two oral delayed-release mesalamine formulations in healthy adult volunteers. Methods: A randomised, open-label, parallel-group study of mesalamine pharmacokinetics following Lialda 2 × 1.2 g once daily (QD) (dose A), Asacol 6 × 400 mg QD (dose B), or Asacol 2 × 400 mg three times daily (TID) (dose C) over 7 days. Assessments included 5-aminosalicylic acid (5-ASA) and N-acetyl 5-aminosalicylic acid (N-Ac-5-ASA, primary metabolite) pharmacokinetics (Ae(%), AUC0-24 and Cmax), safety and tolerability. Results: All enrolled volunteers (n = 37) completed the study. Steady state was achieved for all treatments by day 4. Ratios (95% CI) of means for steady-state AUC0-24 (dose A vs B 90.3% [39.8, 204.8], dose A vs C 123.5% [55.3, 275.7], dose B vs C 136.8% [61.3, 305.5]) and Cmax (dose A vs B 106.0% [46.4, 242.2], dose A vs C 133.0% [59.1, 299.0], dose B vs C 125.5% [55.8, 282.1]) were similar for all 5-ASA treatments. Mean urinary excretion of 5-ASA plus N-Ac-5-ASA was comparable between treatments (dose A 21.3%, dose B 20.2%, dose C 17.9%). All treatment regimens were well tolerated; no safety issues were observed. Conclusions: Plasma and urine pharmacokinetics for Asacol TID, Asacol QD, and Lialda QD are similar, suggesting similar daily systemic exposures can be obtained with either TID or QD dosing. NCT00751699.