Microbiotica raises £36M to test gut-bacteria capsule in ulcerative colitis
U.K. microbiome company Microbiotica has raised £36 million (€43 million), the first close of a Series C round led by the British Business Bank, to take its ulcerative colitis drug MB310 into Phase 2.
Why it matters: Many people with ulcerative colitis do not reach or stay in remission on existing drugs. Microbiotica designed MB310, a once-daily capsule of eight live gut bacterial strains, to deliver lasting remission without suppressing the immune system.
- “We believe Microbiotica is emerging as a world leader in the development of microbiome therapeutics,” said Carmine Circelli, senior investment director for life sciences at the British Business Bank, in a press release.
Follow the money: The British Business Bank is the U.K. government’s economic development bank. The Series C also attracted Tencent, IP Group, Cambridge Innovation Capital, Flerie Invest and Seventure Partners, with all existing Series B investors participating.
- Microbiotica previously raised £50 million (€59 million) in 2022 to bring its microbiome treatments into clinical development. Existing investors added undisclosed funding in 2024 to see its clinical trials through. In February, Microbiotica put its equity raised at more than £62 million (€73 million) and said it would explore partnering and financing options during 2026.
Zoom in: Microbiotica reported in February that 12 of 19 patients on MB310 reached clinical remission, against three of 10 on placebo, in COMPOSER-1, a Phase 1b study of 29 adults with mild-to-moderate disease.
- Patients took the capsules or placebo once a day for 12 weeks on top of their usual treatment, at sites in the U.K., Austria, Bulgaria, Poland and Spain.
- MB310’s strains began taking hold in patients’ guts as early as the first week, and all eight persisted through three months of follow-up.
- The strains were picked from a fecal-transplant study run with the University of Adelaide: bacteria that colonized patients’ guts and were associated with clinical response.
Reality check: MB310’s evidence is early, a European rival is a stage ahead, and two others failed in Phase 2.
- COMPOSER-1 was built mainly to test safety, its primary objective, which it met.
- Its remission figures come from the partial Mayo score, which rates stool frequency, rectal bleeding and a doctor’s overall assessment but leaves out endoscopic findings.
- Belgium’s MRM Health, which raised €55 million in 2025, is recruiting about 204 patients in Europe and the U.S. for a Phase 2b of MH002, its six-strain bacterial mix, with first results due in the fourth quarter of 2027.
- Vedanta Biosciences’ VE202, also a defined bacterial mix, missed its main efficacy goal, an improvement seen on endoscopy, in a 114-patient Phase 2 in August 2025.
- Seres Therapeutics’ SER-287, made from donor-derived bacteria, missed its main goal, clinical remission, in a 203-patient Phase 2b in July 2021, although its bacteria took hold in patients’ guts.
What’s next: In February, Microbiotica said it was planning a Phase 2/3 testing MB310 alongside anti-inflammatory or immune-modulating drugs given to induce remission. The randomized, double-blind, placebo-controlled Phase 2 it now plans will test whether a remission signal from 29 patients, scored without endoscopy, holds up at the stage where VE202 and SER-287 failed.
