After decades of research, the first vaccine to treat cancer has won approval from the Food and Drug Administration. In a milestone decision, the FDA today approved Provenge (sipuleucel-T) for men with metastatic prostate cancer that is resistant to hormonal therapy.Provenge uses the patient's own immune cells to activate the body's immune response to seek out and destroy cancer cells. (View an illustration of how Provenge works.)This was the second try for Provenge, after the FDA chose not to approve the vaccine in 2007, despite a unanimous vote in favor of approval by a panel that advises the FDA. Dendreon, the maker of Provenge, later submitted more data.According to the FDA, the approval was based on results from a phase 3 trial showing Provenge extended overall survival by 4.1 months in men with metastatic hormone-refractory prostate cancer. The median overall survival--meaning some patients lived a longer period of time, and some lived shorter--reached 25.8 months for patients receiving Provenge, compared with 21.7 months for those not receiving the vaccine. Common side effects of Provenge include chills, fever, and headaches during the intravenous administration.Dendreon has not announced how much the vaccine will cost.Check out "Getting Personal" from the Spring 2010 issue of CURE for more about Provenge and other vaccines to treat cancer.