Dendreon stock price surges

NEW YORK (CNNMoney.com) -- Dendreon's stock price surged immediately after the open of Friday trading, following an surprise positive vote from FDA advisors the day before, which favored the experimental prostate cancer treatment Provenge.

Dendreon's (up $8.63 to $13.85, Charts) stock price nearly tripled in the first few minutes of trading, to $14.90 a share.

About 25 percent of Dendreon's stock was sold short prior to the vote, meaning that many investors expected bad news from the FDA on Thursday. Instead, the positive advisory vote gave the stock price its unexpected lift.

An expert panel of advisors to the Food and Drug Administration voted 13-4 in favor of Provenge's approval as a vaccine to treat prostate cancer. This is not a binding vote, but it will be taken into consideration by the FDA when the agency decides whether to approve Provenge. The FDA is expected to make this decision in mid-May.

Jonathan Aschoff, analyst for Brean, Murray, Carret & Co., criticized the vote, saying that Provenge failed two late-stage tests. Despite the panel vote, Aschoff said he doesn't expect the FDA to approve the vaccine without requiring more data from the company. Aschoff expects Dendreon's third late-stage test for Provenge, which is currently ongoing, to fail.

Dendreon is a Seattle-based biotech, an industry where cancer treatment plays an important role. Amgen (down $0.09 to $55.74, Charts) and Genentech (up $0.67 to $82.26, Charts), both based in California, are the industry leaders.

Aschoff does not own stock in Dendreon, though Brean, Murray, Carret & Co. make a market in the company.

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