Dendreon's Revenge

Updated from March 29

Dendreon(DNDN Quote) wins.

On Thursday afternoon, an advisory panel of the Food and Drug Administration voted 13-4 to support approval of Dendreon's prostate cancer vaccine, Provenge. The event sent shares soaring 255% early Friday.

The positive panel vote came after a day of testimony and presentations from the company and FDA reviewers examining the safety and efficacy of Provenge. If the FDA follows through on the panel's recommendation, Provenge will become the first vaccine, or immunotherapy, ever approved to treat cancer.

The FDA is expected to make its final approval decision by May 15.

Early Friday, shares rose $13.33 to $18.55.

Provenge works by stimulating the patient's own immune system to recognize and kill prostate cancer cells. In a phase III clinical study, patients taking Provenge lived 4.5 months longer than patients given a placebo.

Dendreon shares were halted all day on Thursday but closed Wednesday at $5.22.

There are approximately 232,000 new cases of proatate cancer diagnosed each year in the U.S., making it the most diagnosed cancer in men in this country. More than 30,000 men die from the disease each year, second only to lung cancer.