The hormone treatment, Johnson & Johnson’s Zytiga, when added to a standard steroid therapy doubled the time it takes for the disease to progress in patients treated with the standard therapy alone, said the lead researcher, Dr. Charles Ryan, associate professor of clinical medicine at the UCSF Helen Diller Family Comprehensive Cancer Center.

The U.S. Food and Drug Administration last year approved Zytiga, also known as abiraterone, for use in men whose prostate cancer had spread to other parts of their body and had already been treated with chemotherapy.
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This trial focused on patients whose cancer had metastasized, may have been treated with other hormone therapies but had not yet gone through chemotherapy.
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Prostate cancer, the second most common form of cancer in males after only lung cancer, is diagnosed in about 200,000 men in the United States each year. And while it is generally treatable, the disease kills nearly 30,000 men a year.

Because their disease is often slow-growing, about a third of patients diagnosed with prostate cancer won’t be treated. Another third will undergo successful treatment, which could include surgery, various hormone therapies or chemotherapy.

Still, a third of patients will have recurrent or aggressive disease that may have been caught too late. Ryan said men tend to die when the cancer spreads outside the prostate, mostly to bone, and the patient becomes resistant to hormonal therapy. The cancer cells rely on testosterone to exist, so typically doctors treat patients with testosterone-blocking hormone therapy.

But patients become resistant when the cancer cells develop the ability to make their own hormone and learn to survive even in the face of the testosterone-blocking drugs, giving the disease the ability to progress, Ryan said.

Zytiga is the first FDA-approved drug that can go inside the cancer cell and block it from making its own testosterone.

The trial involved 1,088 men who were being treated by 151 cancer centers in 12 countries. Each was given a low dose of the steroid prednisone, which works to combat the cancer