Once daily versus conventional dosing of pH-dependent mesalamine long-term to maintain quiescent ulcerative colitis: Preliminary results from a randomized trial.

Background And Aims: Multiple studies have demonstrated the efficacy of aminosalicylates in maintaining remission in ulcerative colitis (UC). A newer formulation of mesalamine can be administered once daily. We aimed to examine the efficacy and tolerability of pH-dependent mesalamine for long-term maintenance, and compare the rates of medication consumption between groups over a prolonged period.

Methods: Subjects whose UC had been quiescent for at least 4 months, and who had been receiving mesalamine for maintenance only, were randomized to once daily or conventional dosing for 12 months. Disease activity and medication consumption was assessed every 3 months. The primary endpoint was the percentage of those with quiescent disease at 12 months.

Results: We enrolled 20 patients, 12 to once daily and 8 to conventional dosing. Six of the 12 patients (50%) in the once daily group compared with 5 of the 8 patients (62.5%) in the conventional group experienced a flare (p = 0.31). Only 5 of the 12 (42%) patients in the once daily group were adherent compared with 3 of 8 patients (37.5%) in the conventional dosing group (p = NS). Median amount consumed in the once daily group was 63% (range 0%-100%) and in the conventional group 55% (range 0%-100%), (p > 0.5). None of the adherent subjects in the once daily group experienced a flare, while 6 out of 7 (86%) who were non-adherent experienced a flare (p < 0.01). In the conventional dosing group, 1 in 3 adherent patients (33%) experienced a flare compared with 4 out of 5 (80%) in the non-adherent group (p < 0.01).

Conclusion: Adherence, rather than medication regimen, appeared to be important in disease outcome at 12 months.