Talimogene laherparapvec (Imlygic) is the first FDA-approved oncolytic virus therapy. The agent is indicated for the treatment of melanoma lesions in the skin and lymph nodes that cannot be removed surgically.

Melanoma is a type of skin cancer, which is the most common type of cancer in the United States. The National Cancer Institute estimates melanoma will be diagnosed in approximately 74 000 Americans and nearly 10 000 patients will die of the disease in 2015. Melanoma is most often caused by exposure to ultraviolet (UV) light and is the most common cause of skin cancer-related deaths.

“Melanoma is a serious disease that can advance and spread to other parts of the body, where it becomes difficult to treat,” said Karen Midthun, MD, director of the FDA Center for Biologics Evaluation and Research.

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Talimogene laherparapvec is a genetically modified live oncolytic herpes virus therapy indicated for the treatment of melanoma lesions that cannot be surgically removed. Its mechanism of action is to replicate inside cancer cells, causing the cells to rupture and die.

Talimogene laherparapvec is administered as a series of injections directly into the melanoma lesions. Treatment begins with an initial injection, with a second dose administered 3 weeks later.

Consequent doses are administered every 2 weeks for at least 6 months, unless the patient requires other treatment or until the patient has no more injectable lesions to treat.

A multicenter study of 436 patients with unresectable metastatic melanoma was conducted to evaluate safety and efficacy. Study participants received the oncolytic virus therapy or a comparator therapy for at least 6 months or until no injectable lesions remained.

A decrease in size of the skin and lymph nodes lesions was seen in 16.1% of participants who received the therapy, compared with 2.1% of participants receiving the comparator therapy.

Talimogene laherparapvec, however, did not improve overall survival or have an effect on melanoma metastasis to the brain, bone, liver, lungs, or other internal organs.

Side effects most commonly reported by study participants included fatigue, chills, fever, nausea, flu-like symptoms, and pain at the injection site. This therapy is a modified live oncolytic herpes virus therapy therefore herpes virus infection can occur. It is contraindicated in persons with a suppressed immune system and pregnant women.


1. US Food and Drug Administration. FDA approves first-of-its-kind product for the treatment of melanoma [press release]. FDA Web site. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm469571.htm. Accessed October 28, 2015.