Seres Therapeutics Ditches Its SER-301 Phase 1b Second Study In Ulcerative Colitis

In its SEC filing, Seres Therapeutics Inc MCRB disclosed it would not move forward with the planned SER-301 Phase 1b second study cohort.
In its Q4 earnings release, Seres said that SER-301 was safe to proceed to the placebo-controlled second cohort in a Phase Ib trial even though outcome data from the 15 patients indicated none of them had achieved clinical remission after 10 weeks of treatment.
The Company plans to continue research activities evaluating ulcerative colitis based on SER-287 and SER-301 trial data.
"Clinical data suggest the potential for biomarker-based patient selection," Seres revealed in the presentation.
In March, the Company said SER-301 led to improvements in endoscopic, stool frequency, and rectal bleeding sub-scores for some patients.
Seres plots for a mid-year approval request for its C. difficile therapeutic, SER-109.
Related: Seres Therapeutics' Oral Microbiome Candidate Shows Meaningful Improvements In Difficile Infection.
In a Phase 2b study last year, Seres said SER-287 did not improve clinical remission rates compared to placebo.
Price Action: MCRB shares are down 0.69% at $7.21 during the market session on the last check Thursday.