Dendreon shares jump ahead of Provenge data

NEW YORK, April 3 (Reuters) - Shares of Dendreon Corp (DNDN.O) jumped 38 percent on Friday as investors looked ahead to long-awaited data on the company's experimental Provenge vaccine to treat advanced prostate cancer.

A spokeswoman for the U.S. biotechnology company, Katherine Stueland, said she knew of no clear reason for the stock gains. But she noted that the American Urological Association on Friday had reserved a time slot at one of its upcoming scientific meetings for Provenge researchers to present findings from a late-stage trial of the product.

"We don't know whether we'll definitely be releasing the data there," said Stueland, who noted that the urological group had invited it to make a "late-breaker" presentation on April 28 at its meeting in Chicago.

Late-breaker presentations at medical meetings usually involve high-profile studies, or ones of particular interest to healthcare professionals. However, selection of studies as a late breaker is no indication whether the data will be positive or negative.

Stueland reaffirmed that Dendreon expects to release the Provenge data by the end of the month, even if the urological group's meeting is not the chosen forum.

The study includes more than 500 men with late-stage prostate cancer who have not benefited from drugs that sharply lower testosterone -- the male sex hormone which fuels progression of the cancer.

If the trial succeeds, the vaccine could become the first approved cancer immunotherapy, meaning a drug to fight cancer by stimulating the immune system to attack cancer cells.

Shares of Dendreon closed up $1.65 to $5.99 on the Nasdaq. (Reporting by Ransdell Pierson; editing by Carol Bishopric)