FDA OKs Vaccine Therapy for Prostate Cancer

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Vaccine Called Provenge Works by Revamping Immune System to Recognize Cancer

A new treatment for prostate cancer offers new hope to men.

Earlier clinical trials of the vaccine, called Provenge, showed that the

therapy could extend life by four to five months in men with advanced

prostate cancer. But in 2007, the FDA asked for more research since studies

curiously showed that Provenge seemed to extend life without slowing the

progression of cancer.

" This is real big step, " said Dr. Penson, a researcher on the original

Provenge studies and a professor of urologic surgery at Vanderbilt

University in Nashville, Tenn. " You're using your body's own immune system

to fight the cancer. In the future we hope it will make treatment more

effective with few side effects. "

Rather than obliterate new cells in the body as chemotherapy does, Provenge

works by boosting the patient's own immune system.

Provenge Takes Intriguing Approach to Cancer

" It's not a miracle, but it's amazing that the immune system can still wake

up even when a man has prostate cancer throughout his body, " said Dr.

Simons, president and CEO of the Prostate Cancer Foundation.

" In 1993 if you told someone that you could wake up the immune system to

fight prostate cancer, they would have laughed you out of the room, " said

Simons.

About 18 years ago, Simons said scientists discovered that cells in our

immune system called dendritic cells act as detectives that hunt down and

identify potential invaders like cancer. The dendritic cells then " awake " or

activate other cells in the immune system such at T-cells or B-cells to seek

and destroy the cancer invaders.

Simons said it wasn't until 2000 that researchers believed the immune system

of a person with severe prostate cancer could " wake up " and start to

recognize the cancer as a disease.

Provenge works unlike other vaccines in which a standard dose is

manufactured and distributed to doctors.

Men who are candidates for the vaccine must give a blood samples. The white

blood cells are isolated, shipped to a specialized lab, and treated in a way

that " trains " the white blood cells to recognize and attack cancer.

Small Steps Towards Extending Lives

Penson said a study of 500 men with metastasized, hormone-resistant prostate

cancer confirmed the earlier finding that Provenge extends life by an

average of four months. Men at that stage of prostate cancer usually have

only one treatment option left -- a drug called Docetaxel, which has a " fair

number " of side effects compared to Provenge.

" It has a survival benefit over placebo from three to four months, " said

Penson. " You know people look at me and say you know three to four months

you're not curing anybody... but for someone who'd have 18 more months to

live, you get 20 percent more life. "

Several more months of life might not be considered a " home run, " but the

method of treatment and the small step in a new direction has prostate

cancer advocates and other cancer researchers excited.

" All of us want to see home runs, but the reality is we don't have something

like that, " said Dr. Nina Bhardwaj, director of the Tumor Vaccine Program at

New York University Langone Medical Center in New York City. " Even in cancer

when new chemo drugs are coming out if you can improve survival by four to

six months, it's a big step. "

" This represents a small but significant improvement and supports approaches

that use of cell-based vaccines to treat cancer, " said Bhardwaj.

However, as Bhardwaj predicted, cell-based vaccines like Provenge will be

expensive. Patients have to pay for the expensive process of extracting the

blood, the processing of the blood and the transport of all the samples.

" Being individualized therapy like that makes it expensive -- just like the

bone marrow transplant, " said Bhardwaj.

A spokesman from Dendreon, the company that makes Provenge said the company

" has not yet set the price, however we expect it will be similar to other

novel biologics that prolong survival. "

Other " novel biologics " run from $50,000-$100,000 for a course of treatment.

However experts still see Provenge as a door to more research for various

forms of cancer.

" We can now look forward to additional studies of this approach in breast

cancer and melanoma, and eventually in other diseases, " Dr. Otis Brawley,

chief medical officer for the American Cancer Society said in a statement.

" Many experts feel the real impact of this immunotherapy approach may be

more significant for cancer overall than for prostate cancer alone. "