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Seres Therapeutics Shares Go Parabolic on Positive Topline Data from Phase 3 C.Diff Trial

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Seres Therapeutics shares traded 350% higher setting a new 52-week high after the firm reported positive topline results from its SER-109 Phase 3 ECOSPOR III study in recurrent C. difficile infection.

Seres Therapeutics Inc. (MCRB:NASDAQ) today reported "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)."

Seres Therapeutics advised that the trial results demonstrated that SER-109 resulted in an absolute decrease of 30.2% in the proportion of patients who experienced a recurrence in CDI within eight weeks of administration versus placebo and noted that this was a highly statistically significant result. The firm noted that in the study only 11.1% of patients administered SER-109 experienced a CDI recurrence, compared to 41.3% of placebo patients.

The company additionally stated that as the efficacy results in the study exceeded the statistical threshold previously determined in consultation with the U.S. Food and Drug Administration (FDA), it believes that this might possibly allow this single clinical study to meet the efficacy requirements for a Biologics License Application (BLA). Thus, the company indicated that it intends to immediately request a Breakthrough Therapy designation meeting with the FDA to verify the requirements necessary to submit a BLA for requesting regulatory approval of SER-109.

Seres Therapeutics' President and CEO Eric D. Shaff commented, "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...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 company's Chief Medical Officer Lisa von Moltke, M.D., FCP, added, "Based on these highly positive SER-109 ECOSPOR III results, we believe that this novel microbiome therapeutic candidate could potentially provide a much-needed effective oral treatment option for the approximately 170,000 patients in the U.S. that suffer from recurrent CDI annually."

Mark Wilcox, M.D., Professor of Medical Microbiology, University of Leeds, remarked, "Recurrent C. difficile infection is a serious disease that devastates patients' quality of life, and in many severe cases may result in a patient's death. Today's treatment options have important shortcomings related to efficacy, safety and route of administration, and novel approaches that target the root causes of the disease are urgently needed. The SER-109 Phase 3 results are highly impressive and represent an exceptional advance in the fight against this disease. I believe that SER-109 has the potential to fundamentally transform the treatment of recurrent C. difficile infection."

The company advised that the ECOSPOR III study is a multicenter, randomized study that enrolled 182 patients with multiply recurrent CDI. The primary endpoint objective in the study was the proportion of patients with recurrent CDI at up to eight weeks following administration of SER-109 or placebo and the firm indicated that SER-109 met the study's primary endpoint with a significantly lower recurrence rate of 11.1% in SER-109 patients compared to 41.3% in placebo patients after eight weeks.

The firm stated that "SER-109 is an investigational, oral, biologically-derived microbiome therapeutic that is designed to reduce recurrence of CDI, enabling patients to achieve a sustained clinical response by breaking the vicious cycle of CDI recurrence and restoring the diversity of the gastrointestinal microbiome." The company noted that ER-109 was previously granted both Breakthrough Therapy designation and Orphan Drug designation for the treatment of CDI by the U.S. FDA.

The company explained that according to the Centers for Disease Control and Prevention, CDI is one of the top three most urgent antibiotic-resistant bacterial threats in the U.S. and is a leading cause of hospital-acquired infection in the U.S. and results in approximately 20,000 American deaths yearly.

Seres Therapeutics is based in Cambridge, Mass., and is microbiome therapeutics platform company focused on developing novel multifunctional bacterial consortia designed to functionally interact with host cells and tissues to treat disease. The firm noted that its SER-109 program achieved the first-ever positive pivotal clinical results for a targeted microbiome drug candidate being advanced for the treatment of recurrent CDI. In addition to the SER-109 program, the company also is working on several other drug candidates including SER-287, which is currently being evaluated in a Phase 2b study in patients with active mild-to-moderate ulcerative colitis, SER-401 in a Phase 1b study in patients with metastatic melanoma, SER-301 for ulcerative colitis and SER-155 to prevent mortality due to gastrointestinal infections, bacteremia and graft versus host disease.

Seres Therapeutics started off the day with a market capitalization of around $353.8 million with approximately 76.26 million shares outstanding and a short interest of about 10.6%. MCRB shares opened more than 330% higher today at $20.13 (+$15.49, +338.84%) over Friday's $4.64 closing price and reached a new 52-week high price this morning of $33.00. The stock has traded today between $18.00 and $33.00 per share and is currently trading at $20.93 (+$16.29, +351.08%).


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