Why Gene Therapies Must Go Virus-Free

Gene therapies have made spectacular progress in delivering new cures for previously intractable disease, but they remain the world’s most expensive treatments. Now companies are replacing the virus in gene therapies with new delivery technologies that promise not only to overcome the limitations of viral vectors but to slash production costs too.

Virus-based vectors — particularly those based on adeno-associated virus (AAV) and lentiviruses — have dominated the first wave of gene therapies to gain regulatory approval. But their widespread deployment in dozens of clinical trials has exposed their limitations. To provide a viable alternative, non-viral technologies need to satisfy certain well-defined requisites. They must accommodate a large payload and deliver it to specific organs, lack immunogenicity to allow redosing, and have a high safety margin and low production costs. Although most are still preclinical, the field is gaining momentum.