Longeveron stem cell therapy misses goal in infant heart trial, shares slump

Longeveron said on Wednesday that it will review its strategic options after its experimental stem cell therapy failed to achieve the primary goal of a mid-stage trial in infants with a rare congenital heart defect. The company's shares, which had risen 32% so far this year, fell nearly 60% in after-hours trading following the disclosure.

The trial evaluated laromestrocel alongside standard surgery in 40 infants born with hypoplastic left heart syndrome, a severe birth defect in which the left side of the heart is underdeveloped. According to the company, the therapy did not improve how effectively the right side of the heart pumped blood after 12 months when compared with standard care alone.

Longeveron reported no deaths over the 12-month period among infants who received laromestrocel, against one death in the standard-care group. In a subset of patients followed for as long as five years, one death or heart-transplant event occurred among 17 patients in the treatment group, compared with two such events among 21 patients in the standard-care group.

The company said the therapy was safe and well tolerated, with no new safety concerns identified. It plans to examine the data and meet with the U.S. Food and Drug Administration to discuss possible next steps for the program.

Longeveron added that it has begun a process to review all options with the aim of maximizing shareholder value, while taking steps to reduce costs. The company intends to redirect resources toward developing the therapy for longevity and aging-related frailty.