JX-594 is an oncolytic virus is designed to target and destroy cancer cells.[1] It is also known as Pexa-Vec,[2] INN pexastimogene devacirepvec[3]) and was constructed in Dr. Edmund Lattime's lab at Thomas Jefferson University, tested in clinical trials on melanoma patients, and licensed and further developed by SillaJen.
JX-594 is a modified Copenhagen[4] strain (or Wyeth strain[3]) vaccinia poxvirus engineered by addition of the GM-CSF gene and deletion of the thymidine kinase gene which limits viral replication to cells with high levels of thymidine kinase, typically seen in cancer cells with a mutated RAS or p53 gene.[5] The virus also has the LacZ gene insertion under control of the p7.5 promoter.[3] The virus kills the infected/cancer cells by lysis and also expresses GM-CSF which may help initiate an anti-tumour immune response.[6][7] [8]
It has orphan drug designation from US Food and Drug Administration and EUMA[clarification needed] for the treatment of hepatocellular carcinoma (liver cancer).[2]
In clinical trials doses have been administered by intratumoral or intravenous injection.[3]