Seres Therapeutics, Inc. (NASDAQ: MCRB) stock has skyrocketed more than 350% after the a microbiome therapeutics platform company announced positive topline results from the pivotal Phase 3 ECOSPOR III study evaluating its investigational oral microbiome therapeutic SER-109 for recurrent C. difficile infection (CDI). The study showed that SER-109 administration resulted in a highly statistically significant absolute decrease of 30.2% in the proportion of patients who experienced a recurrence in CDI within eight weeks of administration versus placebo, the study’s primary endpoint. 11.1% of patients administered SER-109 experienced a CDI recurrence, versus 41.3% of placebo patients.
The study results were equally compelling when characterized by the alternative metric of sustained clinical response, where 88.9% of patients in the SER-109 arm achieved this objective.
“We are extremely pleased with these highly clinically meaningful SER-109 Phase 3 study results, greatly exceeding the statistical threshold provided by the FDA. Based on our prior discussions with the FDA, we believe this trial should provide the efficacy basis for submitting an application for product approval. We look forward to meeting with the FDA as soon as possible to discuss the regulatory path forward with the goal of bringing SER-109 to patients as a first-in-class microbiome therapeutic,” said Eric D. Shaff, President and Chief Executive Officer of Seres. “Our results represent the first-ever positive pivotal clinical study results for a targeted microbiome drug candidate. We believe these Phase 3 data provide strong validation for our underlying microbiome therapeutics platform, which has been the scientific basis for the Company, as well as persuasive clinical evidence supporting our other active pipeline programs.”
The study’s efficacy results exceeded the statistical threshold previously provided in consultation with the U.S. Food and Drug Administration (FDA) that could allow this single clinical study to fulfill efficacy requirements for a Biologics License Application (BLA). The SER-109 safety results were favorable, with an adverse event profile comparable to placebo.