Additive effect of probiotics (Mutaflor) on 5-ami- nosalicylic acid therapy in patients with ulcerative colitis

School Background/Aims: In ulcerative colitis (UC) patients, Escherichia coli Nissle 1917 (EcN) is equivalent to mesalazine for preventing disease relapse; however, evidence of the ability of EcN to increase health-related quality of life or induce remission remains scarce. We investigated the efficacy of EcN as an add-on therapy for UC. Methods: In this multicentre, double-blind, randomised, placebo-controlled study, a total of 133 UC patients were ran domly assigned to receive either EcN or placebo once daily for 8 weeks. Inflam matory bowel disease questionnaire (IBDQ) scores (primary end -point) and clinical remis sion and response rates (secondary endpoints) were compared (Clinical trial registration number: NCT04969679). Results: In total, 118 patients (EcN, 58; placebo, 60) com pleted the study. The number of patients reaching the primary endpoint did not differ be tween the EcN and place-bo groups (30 [51.7%] vs. 31 [51.7%]; per-protocol analysis, p = 1.0; intention-to-treat analysis, p = 0.86). However, significantly fewer patients in the EcN group exhibited a decreased IBDQ score (1 [1.7%] vs. 8 [13.3%]; per-protocol analysis, p = 0.03; inten-tion-to-treat analysis, p = 0.02). Moreover, a significantly higher number of patients in the EcN group displayed clinical response at 4 weeks (23 [39.7%] vs. 13 [21.7%], p = 0.04) and endoscopic remission at 8 weeks (26 [46.4%] vs. 16 [27.1%], p = 0.03). Conclusions: Although the number of patients reaching the primary endpoint did not differ between the EcN and placebo groups, EcN was found to be safe and effective in preventing the exacerbation of IBDQ scores and achieving clinical responses and endo-scopic remission in patients with mild-to-moderate UC.