New CEO axes 30% of Seres’ workforce to refocus on ‘high priority’ late-stage efforts

Seres Therapeutics has cut about 30% of its workforce and said goodbye to its chief scientific officer as it narrows its clinical efforts. It will instead focus on what it described as its “highest-priority” late-stage microbiome programs for ulcerative colitis and C. difficile infections, as well as a planned immuno-oncology study.

The moves come less than a month after the company announced that its chief financial officer, Eric Shaff, would take over as CEO, and that Seres would look more toward immunological indications as it entered its “next phase of development.” Before that, Seres had brought on AstraZeneca’s immuno-oncology combination program leader, Kevin Horgan, last October to serve as its new chief medical officer and head up its changing pipeline.

This week, the Cambridge, Massachusetts-based biotech said it eliminated about 30 employee positions, plus additional contractors, mostly in research, manufacturing and administrative roles.

The company’s departing CSO, David Cook, will continue to provide immuno-oncology consulting work for the company going forward. He will be succeeded by Seres’ head of discovery and microbiome R&D, Matthew Henn, who joined Seres in 2012 after serving as director of viral genomics and assistant director of the Genome Sequencing Center for Infectious Diseases at the Broad Institute of MIT and Harvard University.

For the near-term, the company will work to complete its recently launched phase 2b study of its SER-287 asset in ulcerative colitis—as well as continuing enrollment in its ongoing phase 3 study of SER-109 for preventing recurrent C. difficile infections.

That trial’s planned recruitment of 320 patients has been slowed, Seres says, because of widespread use of fecal microbiota transplants as an unapproved treatment for C. difficile infections—although the company is considering amending the study’s design to expedite the results.

It will also keep working on a phase 1b study in collaboration with the Parker Institute for Cancer Immunotherapy and MD Anderson Cancer Center, evaluating its SER-401 as a checkpoint inhibitor therapy booster in patients with metastatic melanoma. Seres said it would also continue its preclinical efforts for SER-301, another microbiome candidate for ulcerative colitis.

The company’s release makes no mention as to the fate of its SER-262 phase 1b C. diff program, or its preclinical work on SER-155 for the prevention of infections and graft-versus-host disease following stem cell or solid organ transplants, and Seres did not respond to a request for comment.