Cardiac-targeted rAAV5-S100A1 gene therapy protects against adverse remodeling and contractile dysfunction in post-ischemic hearts

Summary Toxicity by recombinant adeno-associated viruses (rAAV) in clinical gene therapy trials (e.g., by rAAV9-mediated fatal liver failure) significantly impairs translation of preclinical rAAV-based cardiac gene therapies employing these vectors. For rAAV5 - a capsid that has shown long-term safety in clinical trials - our translational study demonstrates effective transduction of the left ventricle (LV) of healthy pigs via catheter-based retrograde intravenous delivery (CRID) by means of luciferase reporter gene biodistribution analyses. Combination of rAAV5 with the cardioprotective human gene S100A1 ( hS100A1 ) prevents LV myocardial infarct (MI) enlargement and improves LV systolic contractile performance in a porcine model of post-MI chronic cardiac dysfunction. Use of a cardiac-biased promoter ensured the cardiac-directed expression of the therapeutic human transgene without signs of clinical toxicity. The beneficial effects of rAAV5- hS100A1 were linked to an attenuated activity of post-MI inflammatory gene networks and this was further validated in a murine model. These novel data together with proven scalable producibility and low pre-existing immunity against rAAV5 in humans may collectively advance clinical translation of rAAV5- hS100A1 as a gene therapy medicinal product (GTMP) for a common cardiovascular disease, such as chronic heart failure (CHF). Highlights Recent fatal adverse events in recombinant adeno-associated virus (AAV)-based clinical gene therapy trials advise the use of rAAV serotypes with proven long-term clinical safety, such as rAAV5, for the pre-clinical development and clinical translation of rAAV-based cardiac gene therapy medicinal products. In a biodistribution and therapeutic proof-of-concept study in farm pigs, rAAV5 was identified as an effective viral vector for cardiac gene transfer and gene therapy for post-ischemic cardiac dysfunction when applied by a standardized cardiac-targeted catheter-based route of administration with the luciferase reporter and cardioprotective human gene S100A1 ( hS100A1 ), respectively. A systems biology analysis linked the novel finding of mitigated inflammatory and activated cardioprotective gene network activities in rAAV5- hS100A1 treated postischemic myocardium with improved study left ventricular ejection fraction and prevention of myocardial infarct extension, respectively, which warrants further mechanistic molecular studies. Since rAAV5 has been recently approved for clinical use in a non-cardiac indication and cardiac-targeted S100A1 gene therapy has been effective in numerous pre-clinical animal models of acute and chronic cardiac dysfunction, our translational data support an expedited developmental path for rAAV5- hS100A1 throughout investigational new drug-enabling studies towards a first-in-human clinical trial for post-myocardial infarction heart failure.