Introduction High concentration 5-ASA formulations have potential to improve patient adherence and increase therapeutic efficacy in ulcerative colitis (UC). We conducted a multicenter, double-blind, randomised placebo controlled trial to assess the efficacy and safety of an 800 mg Octasa^® tablet for induction of remission.

Methods The trial was conducted at 26 centres in Belarus, India, Turkey and Ukraine from November 2009 to May 2011. Eligible patients had active UC with a minimum disease extent of 15 cm from the anal verge, a modified UC disease activity index (UC-DAI) score of 4–10 with a sigmoidoscopic score of ≥2 and a rectal bleeding score of ≥1. Patients requiring other treatments for UC, those with severe disease or those who had previously failed treatment with >2 g/day of 5-ASA were not eligible. Eligible patients were randomly assigned to receive three Octasa^® 800 mg tablets BID or matching placebo for 10 weeks. At Week 6 and Week 10, the proportion of patients in endoscopic remission, defined by a sigmoidoscopic score of ≤1, was compared by the χ² test. Patients who did not undergo sigmoidoscopy were analysed as not being in endoscopic remission.

Results 281 patients were randomised, 140 received Octasa^® and 141 received placebo. Of the 281 randomised patients, 248 had an evaluable post-randomisation sigmoidoscopy. The baseline characteristics were similar between the treatment groups; the mean age was 42.4 and 40.1 years, disease duration was 54.3 and 51.8 months, UC-DAI was 6.7 and 6.6, respectively for Octasa^® and placebo groups. At Week 6, endoscopic remission was achieved in 45.7% of Octasa^® treated patients vs 24.8% of placebo treated patients (p<0.001; 95% CI of the between group difference, 9.7% to 31.3%). The corresponding values at Week 10 were 52.1% vs 36.9% (p=0.010; 95% CI of the between group difference, 3.6% to 26.3%). The mean decrease in the sigmoidoscopic score at the end of treatment was -0.8±0.8 vs −0.5±0.7 respectively for the Octasa^® and placebo treatment groups (p=0.002). The most frequently occurring adverse events were gastrointestinal disorders. Worsening of UC was reported in 9.3% Octasa^® treated patients and 23.1% placebo treated patients.

Conclusion The 800 mg Octasa^® tablet was safe and more effective than placebo for inducing endoscopic remission in patients with active UC.

Competing interests B Feagan: Grant/Research Support from: Tillotts, Consultant for: Tillotts, U Mittmann: Consultant for: Tillotts, D Gilgen: Employee of: Employee of Tillotts, C Wong: Grant/Research Support from: Tillotts, E Mikhailova: Grant/Research Support from: Tillotts, O Levchenko: Grant/Research Support from: Tillotts, Y Marakhouski: Grant/Research Support from: Tillotts.