New Treatment for Melanoma Uses a Form of the Herpes Virus

The American Cancer Society estimates that about 74,000 Americans will be diagnosed with melanoma this year and almost 10,000 will die from this deadliest form of skin cancer. Over the past several years, treatment of advanced cases of melanoma has been transformed as new FDA-approved therapies developed by several different companies have come onto the market. An FDA advisory committee recently approved a therapy that takes a totally novel approach that involves injecting a live attenuated virus directly into regionally or distant metastatic melanoma tumors.

HSV-1 infections cause cold sores and sometimes genital herpes, although infection with human simplex virus 2 is more often the cause of genital herpes. Researchers have characterized the virulence genes of the virus. Talimogene laherparepvec, sometimes shortened to T-VEC, is made by depleting those virulence genes and inserting sequences that generate GM-CSF. It’s believed that removal of the virulence genes decreases the chances that the virus will infect nerve cells and will instead home in on tumor cells. By delivering GM-CSF, the genetically engineered virus enhances tumor antigen presentation to the immune system and induction of immune system attack on the malignancy.

Encouraging durable response results

Talimogene laherparepvec was studied in a randomized, open label phase 3 study to compare the new therapy with GM-CSF injections in subjects with unresectable stage IIIB, IIIC, and IV melanoma. A total of 437 subjects were randomized into the study at 64 study sites. The study was designed to demonstrate an improvement in durable response rate, which was defined as a complete response or partial response maintained for at least six months. Subjects were to receive therapy until Week 24, even if their melanoma was progressing. GM-CSF was used for comparison purposes because at the time that this study was designed, it was also in clinical studies as a treatment for melanoma. It is unclear, though, if GM-CSF by itself has any therapeutic value.

To be enrolled in the study, people had to be age 18 or older, have a histologically confirmed malignant melanoma of the stages listed in the previous paragraph, measurable disease of at least 1 cm, injectable disease (either on the surface of the skin or through the use of ultrasound guidance), ECOG performance of 0 or 1, and a life expectancy greater than four months from date of randomization. The study exclusions included active cerebral disease, any bone metastases, history of secondary cancer unless disease-free for at least five years, open herpetic skin lesions, and primary ocular or mucosal melanoma.

Sourced through Scoop.it from: managedcaremag.com

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