December 11, 2012 | by Tami Dennis
The Food and Drug Administration (FDA) this week approved use of the drug Zytiga, which reduces the production of testosterone, as a front-line therapy for late-stage, castration-resistant prostate cancer. The drug had previously been approved only after use of a chemotherapy drug.
Such advances may lack the impact of a cure, but the fight against cancer is likely to be made in incremental stages, says one City of Hope expert.
“You’re not going to have penicillin for this – it’s not going to happen,” said Cy Stein, M.D., Ph.D., deputy director for clinical research at City of Hope’s comprehensive cancer center and the Arthur and Rosalie Kaplan Chair and Professor of the Department of Medical Oncology and Therapeutics Research.
In this case, Zytiga received its approval for expanded use under an FDA program that offers faster review of drugs that could be significant advances or that could provide treatment for which there’s no good alternative.
The FDA had first approved Zytiga in April 2011 for use after treatment with docetaxel, a chemotherapy drug.
Zytiga itself is significant because of the way prostate cancer develops. Because testosterone causes prostate tumors to grow, drugs or surgery are used to reduce testosterone production or block its effects. But for some men – those with what’s known as castration-resistant prostate cancer – the tumors continue to grow. For those men, Zytiga appears to help.
In a clinical trial of Zytiga, or abiraterone acetate, 1,088 men who had not received chemotherapy were given either Zytiga or a placebo plus prednisone. The men who received Zytiga had a median overall survival of 35.3 months, compared to survival of 30.1 months for men who received a placebo.
“If you get another and another [life-extending drug], and you start to piece them together, you’re going to add years to people’s lives — good years,” Stein said in a recent interview.
In the aforementioned clinical trial, Zytiga also was linked to longer time without further tumor growth, known as radiographic progression-free survival, or rPFS.
“Today’s approval demonstrates the benefit of further evaluating a drug in an earlier disease setting and provides patients and health-care providers the option of using Zytiga earlier in the course of treatment,” said Richard Pazdur, M.D., director of the FDA’s Office of Oncology Drug Products in an announcement of the approval.