GM-CSF  is secreted or released when the cancer cell bursts, attracting dendritic cells to the site, which pick up the tumor antigens, process them, and then present them on their surface to cytotoxic (killer) T cells which in turn sets off an immune response. Composition
Talimogene laherparepvec is a biopharmaceutical drug; it is an oncolytic herpes virus that was created by genetically engineering a strain of herpes simplex virus 1 (HSV-1) taken from a person infected with the virus, rather than a laboratory strain. Both copies of the viral gene coding for ICP34.5 were deleted and replaced with the gene coding for human GM-CSF, and the gene coding for ICP47 was removed. In wild herpes virus, ICP47 suppresses the immune response to the virus; it was removed because the drug was designed with the intention of activating the immune system. History
The first oncolytic virus to be approved by a regulatory agency was a genetically modified adenovirus named H101 by Shanghai Sunway Biotech. It gained regulatory approval in 2005 from Chinas State Food and Drug Administration (SFDA) for the treatment of head and neck cancer. Talimogene laherparepvec is the worlds first approved oncolytic immunotherapy, i.e. it was also designed to provide systemic anti-tumor effects through the induction of an anti-tumor immune response. Talimogene laherparepvec was created and initially developed by BioVex, Inc. under the brand OncoVEXGM-CSF. Development was continued by Amgen, which acquired BioVex in 2011.
Talimogene laherparepvec, sold under the brand name Imlygic, is a biopharmaceutical medication used to treat melanoma that cannot be operated on; it is injected directly into a subset of lesions which generates a systemic immune response against the recipients cancer. The final four year analysis from the pivotal phase 3 study upon which TVEC was approved by the FDA showed a 31.5% response rate with a 16.9% complete response (CR) rate. There was also a substantial and statistically significant survival benefit in patients with earlier metastatic disease (stages IIIb-IVM1a) and in patients who hadnt received prior systemic treatment for melanoma. The earlier stage group had a reduction in the risk of death of approximately 50% with one in four patients appearing to have met, or be close to be reaching, the medical definition of cure. Real world use of talimogene laherparepvec have shown response rates of up to 88.5% with CR rates of up to 61.5%.Around half of people treated with talimogene laherparepvec in clinical trials experienced fatigue and chills; around 40% had fever, around 35% had nausea, and around 30% had flu-like symptoms as well as pain at the injection site. The reactions were mild to moderate in severity; 2% of people had severe reactions and these were generally cellulitis.Talimogene laherparepvec is a genetically engineered herpes virus (an oncolytic herpes virus). Two genes were removed – one that shuts down an individual cells defenses, and another that helps the virus evade the immune system – and a gene for human GM-CSF was added.