Sipuleucel-T (Provenge)

The patient's white blood cells are collected in a procedure similar to blood donation (leukapheresis). In the laboratory, the antigen-presenting cells among them are cultured with a protein that couples a prostate cancer antigen — prostatic acid phosphatase (PAP), found on most prostate cancer cells — to an immune-stimulating factor (GM-CSF). The activated cells are then returned to the patient by infusion; a full course consists of three such cycles, roughly two weeks apart. Back in the body, the activated cells act as instructors: they present the prostate antigen to T cells and prompt them to seek out and attack cancer cells that carry it. Typical side effects are flu-like — fever, chills, fatigue, muscle and joint aches; the NCI also lists rare but serious events, including severe allergic reactions and stroke.