Efficacy and Safety Evaluation of Intravenous MiSaver Stem Cell Therapy in Recent Acute Myocardial Infarction: A Retrospective Phase IIa Study

Abstract Background: Despite advancements in cardiovascular treatments, acute myocardial infarction (AMI) remains a significant health challenge. We aimed to explore the potential of stem cell therapy to improve left ventricular function post-AMI through an open-label, dose-escalating trial. The study aimed to assess the safety and feasibility of intravenous infusion of MiSaver, a prefabricated product of ABO matched allogeneic umbilical cord blood stem cells (USC), in patients following recent AMI. Methods: Participants were enrolled in cohorts of five, receiving escalating dosages of USC (0.5x10^7, 1.6x10^7, and 5.0x10^7 cells/kg). Infusions were administered 2-5 days post-AMI onset. Due to recruitment challenges during the COVID-19 pandemic, this retrospective analysis was conducted using completed low and middle dosage groups and a control group comprising 20 eligible participants meeting similar inclusion criteria. Results: The primary analysis focused on safety and adverse events (AEs) over a 12-month observational period in the treatment group. The treatment was well-tolerated, with no AEs directly attributed to MiSaver. Initial analysis of nine participants showed statistically significant improvements in left ventricular ejection fraction (LVEF) from baseline to 12 months post-treatment compared to the control group (p<0.05); however, significance was lost upon inclusion of participant 10. This participant drew attention to the analysis and exhibited unique characteristics, namely the highest body mass index (BMI) and the youngest age among all participants. Conclusion: This study suggests the potential of MiSaver in enhancing left ventricular function post-AMI. Notably, participants without morbid obesity showed significant recovery in LVEF, suggesting the exclusion of individuals with high BMI in future trials. Larger cohorts and controlled placebo studies are warranted to validate these findings and address trial limitations.