(157v) A Mechanistic Analysis of Recombinant Adeno-Associated Virus Productivity in Biomanufacturing

Recombinant adeno-associated viruses (rAAVs) are increasingly exploited as one of the most important vectors for in vivo gene therapies, including the lately US FDA-approved rAAV-based gene therapies Luxterna^TM (by Spark Therapeutics) and Zolgensma^TM (by Novartis) ^[1]. With the rapid growth of rAAV, current rAAV manufacturing capacity is insufficient to meet emerging demand and there is a need to improve rAAV manufacturing production to keep pace with the clinical and commercial development ^[2]. To date, several methods have been commonly used in rAAV manufacturing, and are based on cell cultivation and a set of genetic elements provided by either transient transfection or viral vector-based gene delivery, or integration into cell genome ^[3]. A key challenge with current methods is that rAAV production is prone to low yields and a large production of empty capsids. This suboptimal performance is not well understood and remains a hurdle in process productivity. To tackle these challenges, we have formulated a detailed mechanistic analysis to understand rAAV production pathways and find out bottlenecks in producing high quality products. This understanding should form a critical foundation to improve productivity and overcome the production of defective products.

In this presentation, we review the mechanisms involved in the common methods used today for rAAV production and the potential limitations and barriers in the production pathways towards high productivity. We will also review the kinetics of wild-type AAV replication, to underline some of the mechanistic differences in the rAAV production in cell cultivation that correlate with viral productivity. Based on these mechanisms, we discuss some strategies applied in literature where molecular or process designs were used to improve rAAV productivity.

Reference

1. Wang, D., P.W.L. Tai, and G. Gao, Adeno-associated virus vector as a platform for gene therapy delivery. Nat Rev Drug Discov, 2019. 18(5): p. 358-378.
2. van der Loo, J.C. and J.F. Wright, Progress and challenges in viral vector manufacturing. Hum Mol Genet, 2016. 25(R1): p. R42-52.
3. Penaud-Budloo, M., et al., Pharmacology of Recombinant Adeno-associated Virus Production. Mol Ther 2018. 8: p. 166-180.