Zytiga approved for metastatic prostate cancer

Today the FDA approved Zytiga (abiraterone) to treat metastatic hormone-resistant prostate cancer. The approval is for patients who have received prior Taxotere (docetaxel).We wrote on Zytiga back in the Winter issue with "Promise for Prostate" when we covered up-and-coming treatments for prostate cancer. Provenge (sipuleucel-T), a vaccine that stimulates a patient's own immune system to fight cancer, had just been approved and another therapy, Jevtana (cabazitaxel), had been approved at near record speed by the FDA.For a disease that hasn't had many new treatment options in nearly 10 years, it is impressive that prostate cancer patients with advanced disease now have three new treatment options. And even more interesting, they all work differently.Provenge is a vaccine--the first therapeutic cancer vaccine to have been approved. Jevtana is a form of chemotherapy called a taxane, the same class as Taxol (paclitaxel) and Taxotere. Zytiga is a hormone therapy that inhibits a protein called CYP17A1, which helps in producing testosterone.Results of a phase 3 study were presented this past October at the annual meeting of the European Society of Medical Oncology in Milan. The international trial randomly assigned 1,195 men to receive either Zytiga and prednisone or prednisone alone. The addition of Zytiga improved median survival from 10.9 months to 14.8 months--a 36 percent increase. The drug also slowed time to disease progression from 6.6 months to 10.2 months. About 38 percent of patients experienced a drop in prostate-specific antigen (PSA) of at least 50 percent from baseline compared with 10 percent on prednisone alone. Side effects included fluid retention, low potassium levels, liver function abnormalities and cardiac disorders.Zytiga had been granted priority review back in late December, which means the FDA would review within six months. The FDA approved Zytiga well before the June 20 deadline.