Efficacy of Bifidobacterium breve Fermented Milk in Maintaining Remission of Ulcerative Colitis

Background: Fermented milk products containing Bifidobacterium breve strain Yakult (BFM) may improve clinical status in ulcerative colitis (UC) patients. Aims: To assess efficacy of BFM in maintaining remission in Japanese patients with quiescent UC. Methods: This double-blind study (B-FLORA) enrolled 195 patients with quiescent UC, randomized to receive one pack of BFM fermented milk per day [Bifidobacterium breve strain Yakult (10 billion bacteria) and Lactobacillus acidophilus (1 billion bacteria)] (n = 98) or matching placebo (n = 97) for 48 weeks. The primary efficacy endpoint was relapse-free survival (relapse: rectal bleeding score ≥ 2 on Sutherland disease activity index scale for 3 consecutive days and/or initiation of remission induction therapy for worsening of UC). Results: An interim analysis was conducted after inclusion and follow-up of one-third of patients for the first phase of the study (n = 195). Relapse-free survival was not significantly different between the BFM and placebo groups (P = 0.643; hazard ratio 1.16; 95% CI 0.63–2.14, log-rank test), nor was the incidence of relapse. Therefore, the study was discontinued for lack of efficacy. An exploratory analysis of fecal samples from a subgroup of patients revealed no effects of either study beverage on intestinal microbiota, but there was a significant decrease in Bifidobacterium species before relapse, regardless of treatment group. Three mild adverse events occurred for which a causal relationship with the study beverage could not be ruled out (placebo: abdominal bloating and stress in one patient; BFM: body odor in one patient). Conclusions: BFM had no effect on time to relapse in UC patients compared with placebo. Study Registration: UMIN000007593.