FDA Panel Backs Prostate Cancer Vaccine

Studies show it extends life of patients with metastatic disease by several months.

By E.J. Mundell and Steven Reinberg
HealthDay Reporters
Thursday, March 29, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

THURSDAY, March 29 (Healthday News) -- A U.S. Food and Drug Administration advisory panel voted Thursday to support approval of Provenge, a vaccine aimed at extending survival for patients with deadly metastatic prostate cancer.

The FDA panel voted unanimously that the vaccine was "reasonably safe," noting that while it failed to meet some study endpoints, it did extend patient survival, according to published reports.

The panel then voted 13-to-4 to say there was substantial evidence to show the vaccine was effective for treating advanced prostate cancer that no longer responds to standard hormone treatment.

The FDA does not have to follow the advice of its advisory panels, but it typically does. The agency is expected to make its final decision by May 15.

Hopes have been high for the vaccine, which researchers said was the first ever shown to have an impact on cancer patients' survival. Those claims were based on a three-year study, released early in 2005, of 127 men with advanced, metastatic prostate cancer.

The trial found that patients infused with Provenge experienced an average 18 percent increase in survival, compared to those on a placebo. That worked out to 4.5 months of extra survival -- 25.9 months for those receiving Provenge vs. 22 months for those not taking the vaccine.

Provenge was developed by Seattle-based Dendreon.

"The concept behind the vaccine is to try to stimulate the patient's own immune system to recognize the prostate cancer cells and keeps them in check," said Dr. Simon Hall, a prostate cancer specialist at Mount Sinai Medical Center in New York City who worked on the trials for the vaccine.

In one phase III trial, men who had metastatic prostate cancer were three to four times more likely to be alive three years after vaccination, Hall said.

"However, the intent of that trial was not to show survival," Hall said. "The intent was to see if you could get patients to delay pain or new lesions in their bones. But they found it had no effect on that."