Dendreon scored a big win on Thursday when an expert FDA committee voted that Provenge is a safe and "substantially" effective therapy against prostate cancer. The panel voted unanimously on the therapy's safety and 13-4 in favor of its efficacy. Investors cheered the news by almost immediately tripling the value of the company's stock. If the FDA now goes on to approve the drug--which is widely expected--Provenge would be Dendreon's first approved product on the market. Analysts peg it as a blockbuster worth more than a billion dollars a year in sales.
The FDA's vote marks their interest and endorsement of immunotherapy. Antigenics, Cell Genesys and Medarex, and others, work in immunotherapy and could see their fortunes rise alongside Dendreon's. Provenge, like a number of immunotherapies in the pipeline, spurs the body's immune system to kill prostate cancer cells by engineering a patient's white cells to recognize them and go on the attack. Perhaps what's most remarkable about the panel's decision is that Provenge failed to hit its primary goal of delaying disease progression in Phase III. Researchers said that it could take weeks for the therapy to charge the immune system, accounting for the data.
Several analysts noted that the FDA took a new tack in its approval when it reworded the question it was asked on efficacy. Instead of determining if the data established efficacy, they determined that there was "substantial" evidence that it worked. One of the trials showed that there was a four month survival benefit for patients in the study. There's an ongoing trial on survival benefit that will finish in 2010. By focusing on "substantial" evidence of efficacy, the panel may have hit upon a new standard for cancer drugs that could affect the chances of a wide number of therapies in the pipeline.
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