Longeveron's Cell Therapy Failed to Help Infants with Severe Congenital Heart Disease; Shares Lost More Than Half Their Value, Putting Funding for the Company's Separate Aging Frailty Program at Risk

Longeveron's Cell Therapy Failed to Help Infants with Severe Congenital Heart Disease; Shares Lost More Than Half Their Value, Putting Funding for the Company's Separate Aging Frailty Program at Risk

On September 16, Longeveron announced that its cell therapy laromestrocel did not improve cardiac function in the phase 2b ELPIS II trial in infants with hypoplastic left heart syndrome. The company's cash reserves were sufficient only through the end of the year. Following the failure, Longeveron announced a review of all strategic options and separately pledged to seek funding for its aging frailty program with the same drug.

In infants with hypoplastic left heart syndrome, a severe congenital defect in which the left side of the heart is underdeveloped, the right ventricle alone takes over the entire work of pumping blood after surgical repair. In the phase 2b ELPIS II trial, 40 such infants received laromestrocel, stem cells derived from healthy donor bone marrow that are intended to suppress inflammation and promote blood vessel growth, injected directly into the heart muscle during open-heart surgery to support the overloaded ventricle. At 12 months, the difference in right ventricular ejection fraction (the proportion of blood the ventricle ejects with each contraction) was −0.7 percentage points, a statistically nonsignificant result. The FDA had warned in advance that ejection fraction alone would not suffice for approval. On more clinically meaningful endpoints, including a 31% reduction in cardiovascular events, the numbers favored laromestrocel, but with a sample of only 40 patients they did not reach statistical significance.

Pediatric cardiac surgeon Sunjay Kaushal of the University of Nevada, Las Vegas wrote in the press release:

There is a significant unmet need to improve the survival of these infants after standard surgery: currently only 50 to 60% survive to adolescence, and about 20% require a heart transplant. ELPIS II provides evidence that stem cells are safe for this application.

Longeveron shares (LGVN, Nasdaq) fell 59% the following day and continued to decline: by the close on September 18, the stock stood at $2.49, giving the company a market capitalization of $7.9 million. ELPIS II was Longeveron's principal asset, the trial whose success the company was counting on to attract investor funding. There was no financial cushion even before the failure: on August 12, Longeveron disclosed in its quarterly filing that $10.1 million in cash would last only through the fourth quarter of 2026 and acknowledged substantial doubt about the company's ability to continue as a going concern.

Longeveron had already been testing the same laromestrocel in a program targeting aging frailty, the decline of physical function in the elderly: in February 2026, a phase 2b trial showed a 63.4-meter improvement over placebo in the walking test. In August, the program was named one of the ten finalists of the XPRIZE Healthspan competition for methods of extending healthy lifespan ($101 million in prizes, approximately 600 applicants) and received $1 million, with the obligation to conduct its own trial within one year.

To stay afloat, Longeveron has hired an investment bank and is discussing next steps for the cardiac program with the FDA. CEO Steven Willard wrote:

The ELPIS II results expand our knowledge of laromestrocel. We see significant potential across multiple indications, particularly in longevity and aging frailty.

The frailty data remain positive, but Longeveron's market capitalization has collapsed to a level where the future of all laromestrocel programs, including the frailty program, depends on whether the company can find new investors for the decisive phase.