Provenge Uses Body's Immune System to Fight Prostate Cancer

April 26, 2010— -- The FDA appears poised to approve a revolutionary new vaccine that could extend the life of prostate cancer patients with far fewer of the harsh side effects of traditional treatments such as surgery, radiation and chemotherapy.

The vaccine, known as Provenge, was developed by Seattle-based Dendreon Corp. It stimulates the body's own immune system to fight cancer cells.

Even though studies show relatively modest benefits to users -- men with advanced prostate cancer who took Provenge lived 4½ months longer, according to early clinical trials -- some men gained an extra two or three years of life after the treatment, and the only side effects were mild flu-like symptoms.

Initial trials were performed only on men whose prostate cancer was at an advanced stage. The hope is that the drug eventually will show promise in patients with earlier stages of prostate cancer.

In 2006, 203,415 men developed prostate cancer, and 28,372 of them died from the disease, according to statistics from the U.S. Centers for Disease Control and Prevention.

The science behind the vaccine could also have applications for other kinds of cancers.

How It Works

Doctors remove patients' own white blood cells, treat them so they respond aggressively to cancerous tumors, then put the treated cells back into the patients' blood.

The treated white blood cells then look for and destroy cancer cells, Dr. Richard Besser, ABC News' senior health and medical editor, said today on "Good Morning America."

Other cells would remain untouched.

Although this represents a major shift in the fight against cancer, the mainstays of cancer treatment remain the same: surgery, radiation and chemotherapy. Besser said Provenge wouldn't be a cure, nor would it replace traditional treatments. But it would be another option, he said.

The worst side effects experienced by trial participants so far have been a few fevers and chills -- easily treated with over-the-counter medications.

Provenge May Hold Hope for Treating Other Cancers

Doctors have been trying for more than 100 years to use the immune system to battle cancer, Besser said. Provenge may be the first in what many hope is a new line of cancer treatments that use the body's own immune system to destroy cancer.

Many cancer patients were disappointed when the FDA failed to approve the treatment in 2007, even though the agency's own advisory panel had voted overwhelmingly in favor of it.

"This technology is innovative and exciting," Dr. E. Roy Berger, a prostate cancer specialist at John T. Mather Memorial Hospital in Port Jefferson, N.Y., told ABC News in 2007.

The drug won't come cheap. Reports say one course of Provenge treatment may cost as much as $75,000, Besser said.

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