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UCSF Oncologist Led Early Clinical Trials of Provenge

By Jeffrey Norris, UCSF Science Cafe | April 28, 2009

Prostate cancer patients who have advanced disease that no longer responds to hormone-blocking therapy might become the first to benefit from a new type of cancer drug.

With these new immunotherapies, the patients' own immune cells are supercharged to better fight the disease, says a UCSF oncologist who has led some of the first clinical trials on immunotherapies for prostate cancer.

Eric Small, MD, director of investigational therapeutics and leader of the Prostate Cancer Program at the UCSF Helen Diller Family Comprehensive Cancer Center, has helped to design and implement clinical trials on a few different immunotherapies. One may soon be under review for approval by the Food and Drug Administration (FDA). The drug, called sipuleucel-T, is made by Dendreon Corp., a Seattle-based biotech firm. Its brand name is Provenge.

Dendreon earlier announced that new clinical trial data -- to be presented today (April 28) in Chicago at the annual meeting of the American Urological Association (AUA) -- indicate that study patients treated with Provenge survived longer.

"This confirms our earlier results," Small says. "This trial represents the second set of phase III data to demonstrate improved survival with Provenge treatment."

Provenge is made from a patient's own immune cells. The cells are called dendritic cells. Like a bounty hunter displaying a culprit's article of clothing to the hounds, a dendritic cell grabs onto a foreign target molecule, or antigen, and displays it to other cells of the immune system. The cells that detect the antigen target are thereby primed to expand their ranks and to attack any tumor that displays the same antigen.

The dendritic cells are obtained through a process called leukapheresis. The cells are exposed to and attach to an antigen called prostatic acid phosphatase (PAP). PAP normally is found on most prostate cancer cells as well as on normal, noncancerous prostate cells, but not on cells from the body's other tissues.

Read more at Jeffrey Norris, UCSF Science Cafe