Panel Evaluates Prostate Cancer Vaccine

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An expert panel convenes Thursday to consider a vaccine for men who have advanced prostate cancer. The panel is evaluating the vaccine for the Food and Drug Administration.

The product is called Provenge, made by a company called Dendreon. It's called a vaccine because it stimulates the immune system. But unlike other vaccines that prevent disease, this one is given to help stop disease in someone who is already sick.

David Penson, a urologist at the University of Southern California's medical school, has been studying the drug for the company. He calls it a "personalized medicine."

"The patient's own immune cells — his white blood cells — are taken out and they're given an agent that activates them to attack the patient's prostate cancer cells," Penson explained.

Penson gave the treatment to patients who were part of a clinical trial, giving 147 men three intravenous infusions of the vaccine over a period of a month. Others received a placebo. Penson is bullish on Provenge, but only for the type of men it was tested on.

"These are men who have cancer all over their body which no longer responds to the traditional hormone therapy," he said.

In two studies, there were essentially no side effects. The drug didn't do any better than a placebo in slowing the progression of the cancer, but there did seem to be a difference in survival. Those who got the drug lived an additional four months, on average. But because of problems with the way the studies were designed, FDA analysts suspect that improvement in people who got the drug might not hold up in further research.

Penson is concerned that a "no" vote by the committee could discourage the development of similar drugs. He's faced with desperate patients, and he doesn't want to see drug companies lose interest. He predicts that future efforts will be more effective.

Christopher Saigal, a urologist at UCLA, has no links to the company or the studies. He says because he wants to offer his patients some ray of hope, he's not concerned about the lack of an effect on the progression of the cancer.

"If it doesn't give them that benefit, they haven't incurred a lot in the way of additional illness," Saigal said.

Cost could be an issue, especially for men without full insurance. Several other new cancer drugs that provide a few weeks or months of extra life cost several thousand dollars a month.

Dendreon officials aren't saying how much they might charge for Provenge if it is ultimately approved. The FDA's final decision is due by May 15.


