Longeveron, a clinical-stage biotechnology company developing cellular therapies for rare paediatric and chronic aging-related conditions, has announced topline results from its Phase2Ib ELPIS II clinical trial evaluating investigational stem cell therapy laromestrocel as an adjunct to Stage 2 palliative surgery in infants with Hypoplastic Left Heart Syndrome (HLHS).

The trial enrolled 40 infants with HLHS and did not meet its primary efficacy endpoint of change from baseline in Right Ventricular Ejection Fraction (RVEF) at month 12. In the intent-to-treat population, the least-squares mean difference between the laromestrocel and control groups was -0.7 percentage points.

Although the study did not demonstrate a significant improvement in RVEF, Longeveron said it is continuing to analyse exploratory clinical endpoints and plans to discuss the findings with the US Food and Drug Administration (FDA) to determine potential next steps for the HLHS development programme.

In as-treated analyses, exploratory outcomes indicated that no deaths occurred among patients who received laromestrocel during the 12-month period, compared with one death in the control group.

During long-term follow-up of transplant-free survival, extending up to five years across all patients, one event was reported among 17 patients in the laromestrocel arm, compared with two events among 21 patients in the standard-of-care arm.

The company noted that these exploratory findings require further analysis and should not be interpreted as evidence of confirmed treatment efficacy.

Laromestrocel demonstrated a safety and tolerability profile that Longeveron said was consistent with its previous clinical experience. Across the company’s clinical development programmes, 644 participants have received the therapy to date.

In ELPIS II, Treatment-Emergent Adverse Events (TEAEs) were reported in 94.1 percent of laromestrocel-treated participants and 100 percent of control participants. Treatment-emergent serious adverse events (TE-SAEs) occurred in 64.7 percent of participants in the laromestrocel group, compared with 71.4 percent in the control group.

No new safety signals were identified, and investigators did not assess any TEAEs or TE-SAEs as related to laromestrocel.

Laromestrocel has received five designations from the US FDA and has demonstrated initial positive findings in aging-related frailty studies. Results from clinical trials in this area have also been published in Cell Stem Cell, and the therapy was selected as a finalist in the XPRIZE Healthspan global competition.

Longeveron is conducting additional analyses of the complete ELPIS II dataset and intends to meet with the FDA to discuss the findings and potential development pathways for HLHS. The agency had previously indicated its willingness to meet with the company following completion of the study.

Separately, Longeveron has initiated a review of strategic options with the stated objective of maximising shareholder value. The company plans to engage an investment bank as a strategic adviser and intends to implement cash-conservation measures to contain costs.

HLHS is a rare congenital heart defect in which the left side of the heart, including the left ventricle, is underdeveloped. This limits the heart’s ability to pump sufficient blood to the body and creates a life-threatening condition.