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P480 Efficacy of switching to pH-dependent release formulation of mesalazine at 3.6 g/day from time-dependent release formulation of mesalazine at 4.0 g/day in patients with Ulcerative Colitis

S. Motoya*, H. Tanaka, M. Miyakawa, R. Sakemi, M. Nasuno, A. Imamura

Sapporo Kosei General Hospital, IBD Center, Sapporo, Japan


In Japan, two different mesalazine formulations, namely pH-dependent release formulation at 3.6 g/day (pH-3.6 g) and time-dependent release formulation at 4.0 g/day (Time-4.0 g) can be administered for high-dose mesalazine treatment of ulcerative colitis (UC). However there are few reports on the efficacy of switching to pH-3.6 g in UC patients who do not sufficiently respond to Time-4.0 g. The aim of this study was to analyze the efficacy of switching to pH-3.6 g in UC patients treated with Time-4.0 g.


Retrospective data was collected from active UC patients who switched to pH-3.6 g because of an insufficient response to Time-4.0 g between January 2010 and November 2013 at the IBD Center, Sapporo Kosei General Hospital, Japan. We excluded patients with a Lichtiger's clinical activity index (CAI) score of ≤ 4 and those who received additional medical treatments within 4 weeks before switching to pH-3.6 g. The efficacy switching to pH-3.6 g was evaluated by the decrease in scores on the CAI. The CAI scores were calculated at baseline, 4 weeks and 8 weeks. Remission was defined as a decrease in the CAI scores to ≤ 4. Prognostic factors related to the remission rate at 8 weeks were evaluated using univariate analysis.


Of the 46 patients (mean age, 40.4 years), 27 were females. The mean duration of the disease was 8.9 years, and the mean CAI score was 6.0 at baseline. Eighteen patients had total colitis, 21 had left-sided colitis and 7 had proctitis-type colitis. Concomitant treatment with both immunomodulators (azathioprine or 6-mercaptopurine) and local mesalazine was administered in 10 patients. Previous treatment included administration of prednisolone in 10 patients. The CAI score at 4 weeks from baseline significantly decreased from 6.0 ± 1.3 to 4.8 ± 2.6 (P = 0.001). The remission rate at 4 and 8 weeks were 50% for both. No significant prognostic factor related to the remission rate at 8 weeks was identified in univariate analysis. However, remission rate tended to decrease for patients previously treated with prednisolone (36%). In addition, the remission rate of the 10 patients to whom local mesalazine was administered was high (70%).


Switching to pH-3.6 g in UC patients not sufficiently responding to Time-4.0 g is effective and should be attempted even if local mesalazine is administered. However, switching to pH-3.6 g from Time-4.0 g may have little effect on UC patients previously treated with prednisolone.