Key Takeaways:
- Intramyocardial autologous bone marrow cell therapy was safe in patients with ischemic HFrEF but did not meet its primary efficacy outcome using the 6-minute walk test.
- Exploratory analyses indicated meaningful clinical improvements, particularly in patients with higher baseline NT-proBNP levels, highlighting a potentially beneficial role for targeted cell therapy in this subgroup.
The CardiAMP-HF trial (NCT02438306), a double-blind randomized controlled study, evaluated the safety and efficacy of intramyocardially delivered autologous bone marrow mononuclear cells (MNCs) in patients with ischemic heart failure with reduced ejection fraction (HFrEF). Results presented at the American College of Cardiology’s Annual Scientific Session (ACC.25) indicated the therapy was safe, but the study was paused by the data safety monitoring board at interim analysis and stopped by the sponsor as the trial was unlikely to meet its primary efficacy endpoint and due to slow enrollment during the COVID-19 pandemic.
The trial randomized 115 symptomatic but stable patients (NYHA Class II-III, LVEF 20-40%) with ischemic cardiomyopathy and favorable bone marrow cell characteristics, as determined by a pre-treatment assay, to either active MNC therapy (n=74) or a sham control procedure (n=41). The therapy involved harvesting, processing, and intramyocardial injection of approximately 200 million autologous cells into specific heart regions identified via echocardiography.
At two years, the primary composite endpoint—a hierarchical analysis combining mortality, left ventricular assist device implantation and heart transplant, non-fatal major adverse cardiovascular events (MACE), and changes in 6MWT distance—did not significantly differ between the groups (win ratio=1.01, p=0.954). However, post-hoc analyses using a modified primary endpoint with quality of life (Minnesota Living with Heart Failure Questionnaire) replacing the 6MWT revealed stronger trends toward clinical benefit (win ratio=1.39; p=0.140 overall, p=0.020 among patients with elevated NT-proBNP >500 pg/mL at baseline). Patients with higher NT-proBNP experienced an 86% relative risk reduction in mortality.
The therapy demonstrated a favorable safety profile, with no device- or procedure-related deaths or major adverse events at 30 days. Three patients developed pericardial effusions, all drained successfully.
Dr. Amish Raval, the study’s lead investigator, concluded: “While the primary endpoint was not met, additional analyses showed encouraging clinical improvements, especially in patients with elevated NT-proBNP. These results suggest autologous cell therapy may benefit a targeted subset of patients with ischemic HFrEF.”