To the surprise of many short-sellers and negative analysts, an FDA advisory committee last month gave Dendreon (NASDAQ:DNDN) a positive response on the company's experimental prostate-cancer therapy, called Provenge. This event didn't mark the primary endpoint of the trials, and there was some controversy over the data analyses, but the endorsement should be a sign of more good news to come.

While we're waiting on the FDA's May 15 deadline for its decision on Provenge, we can say in the meantime that Dendreon at least a good speculative bet. The data shows a survival benefit in two previous trials in prostate-cancer patients.

The advisory committee had been asked whether submitted data established that Provenge was reasonably safe and whether there was substantial evidence that it was effective. The Advisory Committee voted 17 to 0 in favor of its safety of Provenge and 13 to 4 for its efficacy.

Most recently, Bank of America analyst William Ho put the odds of approval of Provenge at 66%, with a $29 price target for Dendreon, based on interviews with FDA panel members and others in the industry. I am inclined to agree that the FDA is likely to approve Provenge, with the only condition being that post-marketing clinical data will need to be submitted and analyzed from an ongoing phase 3 trial of the drug.

The FDA will be under pressure to approve Provenge based on the positive recommendations. Some questions arose about a possible risk of strokes, but Provenge's unanimous safety endorsement from the advisory committee amounts to a pretty clean bill of health. Given the survival benefit and a desperate need for additional cancer therapies, the FDA may just give Provenge the benefit of the doubt and approve it for marketing -- even despite some controversial supporting data.

Dendreon is worth a look for those willing to risk some of their speculative money on what could be at least a double upon approval, given that short interest in the company is currently up to more than 40% of the total shares outstanding. However, the massive short interest also highlights the tremendous risk in Dendreon -- and that's why it is only appropriate as a speculative investment.

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Fool contributor Mike Havrilla, R.Ph., B.S., Pharm.D., is a Rite Aid pharmacist who lives and works in the small town of Portage, Pa. He welcomes your feedback and comments.