Insight Into the Degradation Pathways of an AAV9.

The use of recombinant adeno-associated virus (AAV) vectors is a popular choice for in vivo gene therapy, with hundreds of ongoing clinical trials targeting various genetic diseases. However, due to limited material availability and the complexity of AAV structure, there is a critical lack of comprehensive studies on AAV degradation pathways. In this study, we intended to elucidate the degradation pathways for a model AAV9 with GFP as the transgene under relevant stressed conditions. We assessed a diverse set of critical quality attributes and examined the overall impact of various stresses on transgene expression. This assessment revealed various degradation mechanisms of AAV9 and demonstrated the potential risk of a base formulation in causing AAV9 instability and potency loss under thermal stress at 25 and 40 °C while maintaining stability under freeze-thaw stress, interfacial stress due to membrane filtration, and short-term storage of up to 4 weeks at 5 °C.