Fecal Transplant Pill Fails Trial

Seres Therapeutics’s microbiome-targeting therapy for recurrent Clostridium difficile infection fails a Phase 2 clinical trial.

Written byJef Akst
| 1 min read

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WIKIMEDIA, CDC, HOLDEMANEarlier this year, Seres Therapeutics published promising data from an early-stage trial for its SER-109, a pill containing bacterial spores isolated from stool samples for patients with recurring Clostridium difficile infections (CDIs). The therapy seemed to be effective. But results announced last week (July 29) from a Phase 2 trial of 89 people with recurrent CDI were less positive: researchers found no significant difference between the treatment and control groups.

“The results were surprising, especially since the [Phase] 1b data was eye-popping,” Roger Pomerantz, the company’s CEO and president, told The Atlantic. “We’re now trying to dissect why there was a difference in the two trials.”

While the results may be a setback for SER-109, microbiome-based drugs still look promising, Diane Hoffman, director of the Law and Health Care Program at the University of Maryland and chair of a working group studying microbial transplants, told BuzzFeed News. “I still think it’s really exciting—maybe we just ruled one thing out,” she said. “I have this theory that there’s something potentially unique about the composition of microorganisms together that produces the beneficial effect. When you deconstruct that, you lose some of that benefit.”

Another company, Minnesota-based Rebiotix, ...

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  • Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf Coast of Tampa and performing behavioral experiments at the Tennessee Aquarium in Chattanooga, she left research to pursue a career in science writing. As The Scientist's managing editor, Jef edited features and oversaw the production of the TS Digest and quarterly print magazine. In 2022, her feature on uterus transplantation earned first place in the trade category of the Awards for Excellence in Health Care Journalism. She is a member of the National Association of Science Writers.

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