Seres Faces Disappointment with UC Drug, but Has Another in the Pipeline

Rafael Henrique/SOPA Images/LightRocket via Getty

Rafael Henrique/SOPA Images/LightRocket via Getty Images

Seres Therapeutics, the U.S. biotechnology company specializing in microbiome therapeutics, has announced its clinical study on a potential treatment for ulcerative colitis (UC) failed to meet its primary endpoint. The research is currently on Phase II of the trial.

Seres' ECO-RESET trial aimed to assess the safety and efficacy of using SER-287 in patients who have been diagnosed with moderate UC. Over the 10-week study period, which involved induction dosing after vancomycin pre-conditioning, the researchers reportedly did not observe significant efficacy signals. However, they did find that it was generally well-tolerated. Seres said it has decided to close the study's open-label and maintenance portions given the inability to satisfy endpoint goals. 

The research was conducted as a randomized, double blind, and placebo-controlled study with 203 participants across 104 sites in Canada and the U.S. The trial group had two SER-287 cohorts, one a full induction dose and the other a step-down induction dose, while the other served as the control group. 

Clinical remission in participants with mild to moderate UC was defined using a three-component Mayo Score. At the end of the study, the scientists said no clinical differences were observed in all three treatment groups for endoscopic improvement, endoscopic remission, or symptomatic remission. 

"While the efficacy results in this trial did not meet the pre-defined threshold, we believe this data-rich study, including microbiome analyses expected in the second half of 2021, will provide valuable insights to inform continued development of our pipeline, including SER-301, our next generation investigational candidate for UC," said Lisa von Moltke, M.D., Chief Medical Officer at Seres, in a press release. 

Revealing the next steps for the study, chief executive officer Eric Shaff said that the company keeps to its commitment to finding the best treatment for ulcerative colitis. In the same statement, Shaff mentioned that its other ongoing research involving another component, SER-301, remains on track in Phase Ib trials to find a treatment that would reduce intestinal inflammation and boost epithelial barrier strength in adults with UC. 

The SER-301 study is being conducted in Australia and New Zealand. Both SER-287 and SER-301 are common bacteria found in the gut of healthy individuals. 

Despite the setback, the pipeline remains busy and moving for Seres Therapeutics. Earlier in June, the company announced that the U.S. Food and Drug Administration approved its Investigation New Drug (IND) application for SER-155. SER-155 is an oral, cultivated microbiome therapy designed to reduce the incidence of gastrointestinal antibiotic-resistant bacterial infections, bacteremia, and GvHD in immunocompromised individuals, as well as those receiving allogeneic hematopoietic stem cell transplant (HSCT).

Results from the latest ECO-RESET study on SER-287 are being prepared for presentation at a scientific conference soon.

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