Priority Review for Seres BLA for c.diff Therapy

FDA has accepted for priority review a Seres Therapeutics BLA for its investigational oral microbiome therapeutic SER-109 for preventing recurrent C. difficile infection (rCDI). The agency has set a 4/26/2023 user fee review action target date.

SER-109 comprises purified Firmicutes spores for treating rCDI, which the company says shows promise for improving the current standard of care. The submission is based on data from the company’s Phase 3 development program including ECOSPOR III (NCT03183128) and ECOSPOR IV (NCT03183141) clinical studies. In ECOSPOR III, 88% of patients treated with SER-109 group were free from C. difficile recurrence at eight weeks post-treatment, compared to 60% in those on placebo, it says.

ECOSPOR IV demonstrated a 91% sustained clinical response at eight weeks for those treated with the therapy, and at 24 weeks post-treatment, 86% of subjects treated with SER-109 experienced a sustained clinical response, the company adds.