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The U.S. Food and Drug Administration has approved the use of Imlygic (talimogene laherparevec, also known as T-VEC) for the treatment of patients with melanoma lesions in the skin and lymph nodes. This approval is the FDA's first for an oncolytic virus therapy.

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Imlygic is a genetically modified live oncolytic herpes virus therapy that is intended to treat melanoma lesions that cannot be removed completely by surgery.


The therapy is injected directly into melanoma lesions, increasing selectivity for cancer cells and secreting cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) to promote an immune response. The virus invades both cancerous and healthy cells, but is unable to replicate in healthy cells, leaving them unharmed.


"Imlygic offers a two-pronged approach for the treatment of metastatic melanoma," Lisa H. Butterfield, PhD, Professor of Medicine at the University of Pittsburgh and Vice President of the Society for Immunotherapy of Cancer, said in a news release. "The combination of the virus with GM-CSF increases the drug's cancer-killing effect while activating the immune system to kill melanoma cells-even those that are distant from the treated tumor.


"Imlygic also offers simple administration; it can be injected in an office visit and importantly, has no serious side effects," she said.



After the initial injection of the therapy, a second dose is administered three weeks later, followed by additional doses every two weeks for at least six months, unless other treatment is required or until there are no remaining injectable lesions to treat.


Safety and Efficacy

The safety and efficacy for Imlygic were evaluated in a multicenter study of 436 patients with metastatic melanoma that could not be surgically removed. The participants' melanoma lesions in the skin and lymph nodes were treated with Imlygic or a comparator therapy for at least six months, or until there were no remaining injectable lesions.


Skin and lymph node lesions shrank in 16.3 percent of the patients who received Imlygic, with the response lasting at least six months compared with 2.1 percent of the study participants receiving the comparator therapy.


Imlygic has not, however, been shown to increase overall survival or to have an effect on melanoma that has spread to the brain, bone, liver, lungs, or other internal organs, a news release from the FDA noted.


"This is another possible way of treating a patient's recurrent unresectable melanoma with minimal side effects through a different avenue," the trial's principal investigator Jonathan Zager, MD, FACS, Chair of Graduate Medical Education, a surgical oncologist and Senior Member in the Departments of Cutaneous Oncology and Sarcoma and Director of Regional Therapies at the Donald A. Adam Comprehensive Melanoma Research Center of Excellence, all at Moffitt Cancer Center, said in a news release.


"It is very well tolerated and in the randomized Phase III trial, was shown to significantly improve the durable response rate as well as overall response rates over GM-CSF alone."


The most common side effects for patients treated with Imlygic were fatigue, chills, fever, nausea, flu-like symptoms, and pain at the injection site. The most common grade three or higher adverse reaction was cellulitis. Because Imlygic is a modified live oncolytic herpes virus therapy, herpes virus infection can also occur. Therefore, Imlygic should not be given to individuals with suppressed immune systems or who are pregnant, the FDA also noted.



The average weekly cost of Imlygic therapy is estimated to be $65,000, according to a news release from the drug's manufacturer, Amgen Inc.


"Amgen intends to work with the health care community to implement a program that helps limit the average cost of Imlygic therapy to $65,000 for eligible participating institutions," the news release also noted.


Clinical Quick Facts: Imlygic

Drug: Imlygic (talimogene laherparevec, T-VEC)


Approved Indication: Treatment of patients with melanoma lesions in the skin and lymph nodes


Serious Side Effects: Cellulitis


Common Side Effects: Fatigue, chills, fever, nausea, flu-like symptoms, and pain at the injection site