Yesterday, in after-hours trade Amgen (AMGN) announced that it had received FDA approval for its skin cancer drug known as IMLYGIC. This is an injection immunotherapy drug that helps stimulate the immune system to target and kill cancerous cells. In this case Amgen has received approval for use of IMLYGIC for melanoma - skin cancer. 

IMLYGIC is a modified oncolytic viral therapy that treats local parts of the skin of recurrent melanoma.More specifically IMLYGIC is composed of the herpes simplex virus type 1.  Recurrent in the fact that the melanoma continues to appear even after an initial surgery is performed on the patient. This drug is the first oncolytic viral therapy to be approved by the FDA based on a therapeutic benefit in a pivotal study. 

Amgen states that this drug will be available on the market within one week, and that treatment would cost around $65,000. This approval was made possible to a late-stage phase 3 study known as the OPTiM study. In this study patients achieved durable response rates that met on the primary endpoint of the study compared to a control. 

Durable response rates are classified as those where patients received either a complete response to therapy or a partial response to therapy for six months or longer. In addition to this approval, IMLYGIC received a positive response from European drug reviewers for possible approval in Europe. If all goes well IMLYGIC could also be approved in the European Union as well after its final review from regulatory authorities there.