Seres : Phase 3 Study Shows SER-109 Associated With Reduction Of ARGs In Patients With Recurrent CDI


(RTTNews) – Seres Therapeutics Inc.’s (MCRB) SER-109, an investigational oral microbiome therapeutic for recurrent C. difficile infection or rCDI, was associated with significantly greater reduction of antimicrobial resistance genes or ARGs compared to placebo, with the reduction observed both rapidly (by Week 1) and sustained through Week 8 of the study, as per data from its phase 3 ECOSPOR III study.

The data support a potential role for microbiome therapeutics in rapid decolonization of antibiotic resistant bacteria, the company said in a statement.

Seres expects to file a Biologics License Application (BLA) with the U.S. Food and Drug Administration in mid-2022.

The SER-109 ECOSPOR III Phase 3 study was a multicenter, randomized, placebo-controlled study. Previously reported data indicated that the study achieved its primary endpoint at eight weeks and demonstrated a sustained clinical response rate of approximately 88% at eight weeks post-treatment. SER-109 resulted in a 27% absolute reduction of recurrence of C. difficile infection compared to placebo at eight weeks post-treatment, which is a relative risk reduction of 68%.

In May 2021, Seres presented 24-week clinical data from the study that demonstrated significantly reduced recurrence rates compared to placebo over 24 weeks (21.3% vs. 47.3%, respectively). SER-109 was observed to be well tolerated, with no treatment-related serious adverse events observed in the active arm and an adverse event profile comparable to placebo.