– First ever clinical study of a synthetic microbiome therapeutic –

CAMBRIDGE, MA, USA I July 7, 2016 I Seres Therapeutics Inc. (NASDAQ:MCRB), a leading microbiome therapeutics company, announced today that it has initiated a Phase 1b clinical trial evaluating SER-262 in patients with primary Clostridium difficile infection (CDI). SER-262 is an Ecobiotic® rationally-designed, fermented microbiome therapeutic derived by a manufacturing process that does not require human donor material. SER-262 is the first synthetically-derived and designed microbiome therapeutic ever to reach clinical-stage development.

SER-262, an oral capsule, contains a consortium of twelve bacterial strains in spore form. The strains included in SER-262 were selected based on multiple criteria including analysis of human microbiome data, efficacy in animal models of CDI, and bacterial strain level characterization.1 The composition of SER-262 was selected among Seres’ field-leading human microbiome library containing over 14,000 well-characterized strains of bacteria.

The SER-262 Phase 1b study, a 24-week randomized, placebo-controlled, dose escalation study is expected to enroll approximately 60 patients who have experienced a first episode of CDI. The primary endpoint of the study will compare the CDI recurrence rate between the SER-262 and placebo groups at up to 8 weeks after dosing. Approximately 640,000 and 820,000 individuals in U.S. each year experience a primary occurrence of CDI, and about 25 percent will suffer from a subsequent recurrence.

“Advancing SER-262 to the clinic is a landmark event for Seres and the microbiome field in general. The SER-262 program has demonstrated our ability to rapidly develop a new class of synthetic microbiome therapeutics comprised of rationally designed bacterial compositions,” said Roger Pomerantz, M.D., President, Chief Executive Officer and Chairman of Seres. “We intend to continue to utilize our platform technology and unique knowledge of bioinformatics, microbiology, manufacturing and regulatory requirements to develop additional rationally designed microbiome therapeutics for serious diseases in each of our three therapeutic franchises: infectious disease, immunology and metabolic disease.

With the initiation of the SER-262 Phase 1b study in primary CDI, and the ongoing SER-109 Phase 2 study in multiply recurrent CDI, Seres now has ongoing microbiome clinical programs across the entire CDI population. Initial study results from the SER-109 Phase 2 study are expected in mid-2016.

About Seres Therapeutics
Seres Therapeutics, Inc. is a leading microbiome therapeutics platform company developing a novel class of biological drugs that are designed to treat disease by restoring the function of a dysbiotic microbiome, where the natural state of bacterial diversity and function is imbalanced. Seres’ most advanced program, SER-109, has successfully completed a Phase 1b/2 study demonstrating a clinical benefit in patients with recurring Clostridium difficile infection (CDI) and is currently being evaluated in a Phase 2 study in recurring CDI. The FDA has granted SER-109 Orphan Drug, as well as Breakthrough Therapy, designations. Seres’ second clinical candidate, SER-287, is being evaluated in a Phase 1b study in patients with mild-to-moderate ulcerative colitis (UC). For more information, please visit www.serestherapeutics.com. Follow us on Twitter @SeresTx.

About Clostridium Difficile infection
Clostridium Difficile infection (CDI) is one of the top three most urgent antibiotic-resistant bacterial threats in the U.S., according to the Centers for Disease Control. CDI is a rapidly growing problem associated with antibiotic use. It is a leading cause of hospital acquired infection in the U.S. and is responsible for the death of approximately 29,000 Americans each year. The incidence of first occurrence is between approximately 640,000 and 820,000 patients per year in the U.S., and approximately 85,000 to 110,000 CDI patients in the U.S. have more than one recurrence each year.

Reference:
1Wortman JR et al., Design and Evaluation of SER-262: A Fermentation-Derived Microbiome Therapeutic for the Prevention of Recurrence in Patients with Primary Clostridium difficile Infection; poster at ASM Microbe 2016.

SOURCE: Seres Therapeutics