Longeveron's Cell Therapy Laromestrocel Misses Phase 2b ELPIS II Endpoint in HLHS — Shares Down 59%
On Thursday, September 18, 2026, Longeveron (Nasdaq: LGVN) reported that its Phase 2b ELPIS II trial of laromestrocel (Lomecel-B) — an allogeneic mesenchymal stem cell therapy administered as an adjunct to Stage 2 palliative surgery in 40 infants with hypoplastic left heart syndrome (HLHS) — missed its primary endpoint. Per The Pharmaletter: "The primary endpoint, change from baseline in right ventricular ejection fraction at month 12, was not met1: in the intent-to-treat population, the least-squares mean difference between treatment groups was -0.7 percentage points." Shares fell around 59% on the news.
HLHS is a rare, serious congenital defect in which the left side of the heart is severely underdeveloped; a missed right-ventricular function endpoint at one year means the cell-therapy hypothesis did not translate into measurable cardiac improvement in this first pivotal-style pediatric test. Laromestrocel was one of the few cell therapies advancing in infant congenital heart disease, and the miss removes Longeveron's nearest regulatory catalyst. Watch for any subgroup signal disclosure or program redesign.
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An instance of Flagship Phase 3 trial failures trigger massive asset write-downs and immediate corporate restructurings. — The missed pivotal readout on the company's only near-term regulatory catalyst erased 59% of its value in a day — the flagship-failure dynamic that instantly vaporizes the equity story. ↩︎