The stock was at $9.50 on Thursday, down 54%. It has slumped 61% in the last six months.
At issue is a “Phase 2b ECO-RESET study evaluating SER-287 in patients with mild-to-moderate ulcerative colitis (UC),” Seres Therapeutics said in a statement Thursday.
“The study did not meet its primary endpoint of improving clinical remission rates compared to placebo. Both dosing regimens of SER-287 were generally well tolerated,” the company added.
The company also said that "given the lack of a clinical efficacy signal identified in ECO-RESET, the company has decided to close the open label and maintenance portions of the study."
“While these outcomes were not what we, nor the UC community, were hoping for, we remain committed to leading the creation of a new class of medicines designed to impact how diseases like ulcerative colitis are treated,” said Seres Chief Executive Eric Shaff.
“We are well resourced and continue to prepare for SER-109 commercialization, in collaboration with Nestlé Health Science NESTLE, and we are excited about advancing the development of our SER-301 and SER-155 investigational candidates as well as our earlier stage pipeline,” he added.