The FDA has approved Zytiga (abiraterone acetate) in combination with prednisone for use in patients with late-stage (metastatic) castration-resistant prostate cancer who have received prior docetaxel. The pill was given the green light ahead of its regulatory goal date of June 20, 2011, under the FDA’s priority review program, which provides for an expedited 6-month review for agents that may offer major advances in treatment or provide a treatment when no adequate therapy exists.
Zytiga (marketed by Centocor Ortho Biotech, Inc, Horsham, Pennsylvania) targets the cytochrome P450 17A1 (CYP17A1) protein, involved in testosterone production. Zytiga reduces the production of testosterone, which stimulates the growth of cancer cells. In a clinical study of 1,195 men with late-stage castration-resistant prostate cancer who had previously undergone docetaxel chemotherapy, median overall survival for those receiving the Zytiga-and-prednisone combination once daily was 14.8 months, compared with 10.9 months for men receiving placebo and prednisone twice daily.
The most commonly reported side effects in the Zytiga group included joint swelling or discomfort, low blood levels of potassium, fluid retention (usually in the legs and feet), muscle discomfort, hot flashes, diarrhea, urinary tract infection (UTI), cough, hypertension, heartbeat disorders, urinary frequency, increased nighttime urination, upset stomach or indigestion, and upper respiratory tract infection (URI) (www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm253055.htm).