Chasing Seres, Vedanta bags $107M to run phase 3 C. diff trial of stool-free microbiome therapy

Vedanta Biosciences has found investors willing to bankroll its phase 3 microbiome clinical trial. While a funding freeze recently forced Finch Therapeutics to fold its rival program, Vedanta has reeled in $106.5 million to challenge Seres Therapeutics’ near-approval SER-109 for an infectious disease opportunity. 

Massachusetts-based Vedanta stands somewhat apart from other microbiome drug developers. Seres’ SER-109 and Finch’s CP101 are oral microbiome therapeutics derived from donor stools. Vedanta makes its treatments by growing sets of bacteria from clonal cell banks using scalable fermentation processes, an approach that it has long argued is a more rational, controllable approach.

The latest financing round positions Vedanta to find out whether that idea holds up in the crucible of a phase 3 trial. Using the money, the biotech plans to kick off a pivotal trial of VE303 for the treatment of recurrent C. difficile infection (CDI) in the third quarter.

Vedanta hailed the trial as the “first pivotal phase 3 study of a therapeutic candidate based on a defined bacterial consortium,” but it is nonetheless trailing a candidate based on a similar idea, namely Seres’ SER-109. Seres and Nestlé Health Science are expected to learn whether the FDA will approve SER-109 in CDI on Wednesday.

The timeline, with SER-109 potentially coming to market before VE303 is in phase 3, puts Vedanta at a disadvantage, but the biotech and its backers are betting that its differentiated approval will enable it to come from behind. In a phase 2 clinical trial, Vedanta saw a 13.8% rate of CDI recurrence at Week 8 in recipients of the high dose of VE303. In Seres’ phase 3, 12% of patients had recurrent CDI at week eight.

A syndicate co-led by new investors AXA IM Alts and the AMR Action Fund has come together to find out how VE303 holds up in phase 3. Existing investors including the Bill & Melinda Gates Foundation chipped in cash, as did new backers like K2 HealthVentures and Korea Investment Partners.

The size of the round leaves Vedanta with enough cash to take VE303 into phase 3 while advancing a second asset, VE202, into a phase 2 study in ulcerative colitis. Vedanta expects to start the midphase trial in the second quarter.

Editor's note: This article was updated at 3:30 pm ET to accurately reflect Seres' phase 3 recurrence rate. A previous version of this story listed a recurrence rate from an open-label trial.