Biogen, Roche, Takeda, and Vertex Pharmaceuticals have exited the AAV capsid field. Meanwhile, Pfizer has completely abandoned all work in gene therapy.
This is very unfortunate for the neurodegenerative disease field, where many familial cases could, in theory, be cured with such technologies.
Many gene therapies have received regulatory approval. Most of these approaches use adeno-associated viruses (AAVs) and lentiviruses for gene delivery, in vivo and ex vivo, respectively.
The scientific foundation is solid (we understand how to design vectors and deliver genetic payloads), but industrialization faces many bottlenecks. Manufacturing costs per patient remain very high—hundreds of thousands of dollars.
Since gene therapies primarily target rare diseases, the patient populations are small. Companies cannot rely solely on scaling to lower costs. After the initial cohort is treated, the market shrinks dramatically.
While academia can demonstrate that gene therapies work on a small scale, industry needs to prove that these therapies are reliable, scalable, safe, and financially sustainable—much higher standards. This explains why many promising academic results lead to companies retreating when confronted with the challenges of large-scale production and commercialization.
Alternatives such as mRNA, antisense therapies (ASO), and protein drugs offer different balances of feasibility, durability, safety, and economic viability.