Seres Therapeutics (MCRB) is sharply higher after the company announced plans to initiate a new SER-109 Phase 2 clinical study (ECOSPOR III) in patients with multiply recurrent Clostridium difficile (C. difficile) infection this morning. The ECOSPOR III study design was finalized following a positive Type B meeting with the FDA.
The company reported disappointing Phase 2 data for SER-109 in July and the stock fell 70% in response.
In January, the company reported that a mis-diagnosis and improper dose size were to blame for the failed Phase 2 results.
Seres plans to initiate a new SER-109 clinical study in ~320 patients with multiply recurrent C. difficile infection. To ensure accurate measurement of C. difficile infection, diagnosis of recurrent C. difficile infection for both study entry and for endpoint analysis will be confirmed by C. difficile cytotoxin assay. The prior trial used a PCR test which management now believes results in incorrectly diagnosing patients with post-C. Diff irritable bowel syndrome who don't actually carry the active disease. Patients in the SER-109 arm will receive a total SER-109 dose, administered over three days, ~10-fold higher than the dose used in the prior ECOSPOR study. ECOSPOR III will evaluate patients for 24 weeks and the primary endpoint will compare the C. difficile recurrence rate in subjects who receive SER-109 verses placebo at up to eight weeks after dosing.
Most importantly, the FDA has agreed that this new trial may qualify as a pivotal study with achievement of a persuasive clinical effect and addressing FDA requirements, including clinical and statistical factors, an adequately sized safety database, and certain CMC parameters. It seems the breakthrough therapy and orphan drug designations along with no safety issues to speak of for SER-109 allowed for some lenience from the FDA.
The company will also report data from Phase 1 trials of SER-262 treating primary C. difficile infection and SER-287 treating ulcerative colitis in the second half of 2017.
Seres Therapeutics is a 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.
The company also reported fourth quarter results this morning.
Even after today's increase, cash, equivalents and investment of $230 million account for nearly half of the company's ~$500 million market cap.
Seres CEO Roger Pomerantz still needs to regain the trust of shareholders after the dismal blunder from last summer.
Roughly 15% of the stock's float was sold short coming in to today.