- The FDA has approved Imlygic (talimogene laherparepvec), an oncolytic immunotherapy that uses a genetically modified strain of the herpes virus. It is the first-ever viral oncolytic.
- Imlygic is approved for the treatment of inoperable melanoma.
- Amgen plans to launch Imlygic within a week.
Although the exact mechanism of action is unknown, this is how it works: Imlygic is a genetically modified herpes simplex virus type 1 that is designed to replicate within tumors and produce the immunostimulatory protein granulocyte-macrophage colony-stimulating factor (GM-CSF). Imlygic must be injected directly into the lesions, which ruptures the tumors and introduces antigens.
In clinical studies, 16.3% of Imlygic-treated patients had a durable response rate compared with 2.1% of patients treated with standard of care. This is a significant response, considering how difficult advanced melanoma is to treat.
At this point, the viral oncolytic approach seems to only work on surface lesions, but Amgen is collaborating with other companies to explore the use of Imlygic with other immunotherapies, such as Merck's Keytruda (pembrolizumab), in solid tumors---in this case head and neck cancers. In addition, Roche is studying atezolizumab in combination with Imlygic for treatment of breast cancer.
It seems there are many opportunities ahead to use Imlygic as a starting point for making viral cancer immunotherapy part of the standard of care.