Hormone drug slows prostate cancer growth in clinical trial

Johnson & Johnson's drug Zytiga slowed the growth of prostate cancer in a clinical trial of men who hadn't undergone chemotherapy.

Zytiga was approved by US regulators last year to be used in combination with the drug prednisone to treat men with advanced prostate cancer who have previously tried chemotherapy. The company is sponsoring clinical studies of the drug, which is projected to generate about $1 billion in sales this year, for use at earlier stages of the disease.

The drug works by cutting production of testosterone, a hormone that can stimulate cancer cell growth. Additional details from a clinical trial involving 1,088 men with prostate cancer were presented Saturday at the American Society of Clinical Oncology's annual meeting. Patients in the study are still being followed so the results aren't final.

In March, Johnson & Johnson announced the study exceeded study goals. An independent group overseeing the study recommended it be stopped and men in the control arm be offered Zytiga.

J&J said it plans to submit the results to the Food and Drug Administration later this year and other regulators seeking approval for Zytiga use in men before chemotherapy, a larger group of men than which the drug is currently approved.

The study compared men being treated with Zytiga and prednisone compared with men treated with a placebo, or fake drug, and prednisone. Patients whose disease progressed were then offered chemotherapy.

The study was designed to measure progression-free survival, which is a measurement of the time from the start of treatment until the disease gets worse or the patient dies, and overall survival, which is a measurement of time from the start of treatment until death.

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