Rationally designed chimeric AAV capsids for enhanced immune evasion, cellular uptake, and transduction efficiency

Unmet Need

Adeno-associated virus (AAV) vectors are a leading platform for in vivo gene therapy, yet their clinical potential is limited by key biological barriers. Pre-existing immunity to common AAV serotypes diminishes vector efficacy and prevents redosing, while inefficient cellular uptake and suboptimal trafficking to the nucleus constrain transgene expression. There is an urgent need for next-generation AAV vectors with enhanced immune evasion, improved cellular entry, and more efficient intracellular trafficking to enable durable and effective gene delivery, particularly for systemic therapies targeting tissues such as cardiac and skeletal muscle.

Technology

Duke inventors have developed a novel AAV vector improvement platform capable of enhancing immune evasion and intracellular trafficking. This is intended to improve patient outcomes by increasing AAV vector potency at both initial and subsequent dosing. Specifically, a library-based approach was utilized to evaluate a diverse panel of rationally engineered and naturally occurring phospholipase A2 (PLA2) enzymatic domains, yielding optimized capsid sequences from non-mammalian parvoviruses compatible with the VP1u region of AAV9. This innovative approach to AAV capsid design has produced variants that exhibit enhanced intracellular trafficking and nuclear entry while preserving the natural tissue-targeting properties of AAV serotypes such as AAV8, AAV9, and AAV5. This has been demonstrated in human cells and mice, where the engineered vectors achieved superior gene transfer to key tissues—heart, skeletal muscle, and liver—even in the presence of pre-existing neutralizing antibodies. Increased immune evasion is critical to achieving sustained transduction and supports the potential for vector redosing, overcoming a major barrier to durable gene therapy. The engineered PLA2 domain also demonstrated compatibility across multiple AAV serotypes, providing flexibility for diverse therapeutic applications.

Other Applications

This technology could also be applied to research settings, including boosting transfection efficiency in hard-to-transfect cell types or serving as a tool to study general mechanisms of post-entry trafficking. Insights from this platform may further inform the development of non-AAV delivery modalities, including biologics and lipid nanoparticles, by enabling strategies to improve intracellular delivery and trafficking.

Advantages

• Increased AAV potency at both initial and subsequent dosing.
• Enables transduction despite pre-existing neutralizing antibodies, supporting redosing.
• Improves intracellular trafficking and nuclear entry without altering receptor binding – preserves natural tissue-targeting characteristics of distinct AAV serotypes.
• Compatible across multiple AAV serotypes for broader therapeutic applications.