How are biologics being used in targeted gene therapy?

Targeted gene therapy involves the delivery of genetic material to specific cell types in specific locations in order to alter their function or render them susceptible to other substances (i.e., prodrugs). In cases of rare genetic disorders caused by mutations, gene therapy can be used to replace defectives gene with functional copies. Here, the vector – usually a virus – used to deliver the genetic material is critical, as poor vector selection/design can lead to issues such as immunogenicity and mutagenesis.¹ 

Targeted gene therapy has also been linked with immune-mediated inflammatory diseases and other chronic conditions, but features most prominent in anti-cancer research because of the indiscriminate nature of existing therapeutic approaches such as radiotherapy and chemotherapy.^2,3 Genes selected for targeted delivery typically encode enzymes designed to convert non-toxic prodrugs into cytotoxic agents, and are usually delivered via viral vectors.^2,3

References:
(1) L. Andrews et al., “A snapshot of biologic drug development: Challenges and opportunities,” Hum Exp Toxicol, 34(12):1279-1285, 2015.
(2) I.H. Tarner et al., “Targeted gene therapy: frontiers in the development of 'smart drugs',” Trends Biotechnol, 22(6):304-310, 2004.
(3) V.V. Padma, “An overview of targeted cancer therapy,” Biomedicine (Taipei), 5(4):19, 2015.