Phase II learnings set up microbiome play Seres for Phase III success

Seres parlayed lessons learned from the failed Phase II trial of SER-109 to treat recurrent C. difficile infection into a Phase III win through improved patient selection and higher dosing.

Seres Therapeutics Inc. (NASDAQ:MCRB) added nearly $1.3 billion in market cap on Monday after the company announced topline data from the Phase III ECOSPOR III trial of SER-109 to treat recurrent C. difficile infection (CDI). The 182-patient study met the primary endpoint of an absolute reduction in the proportion of patients experiencing a recurrence of CDI within eight weeks vs. placebo (11.1%  vs. 41.3%; p<0.001)...