Dendreon Still Faces Hurdles for Provenge Despite Positive Phase 3 Data

(MoneyWatch)  Dendreon's announcement that its Phase 3 prostate cancer vaccine Provenge "met its primary endpoint of improving overall survival" in the crucial IMPACT trial will likely have the prostate cancer activists dancing in the streets.

But Provenge still faces significant scientific, regulatory and financial hurdles before it validates the massive expectations heaped upon it.

For years, the Provengistas have argued that it is wrong for the FDA to wait for proof of whether the drug works. Cancer-stricken men should have access to the investigational drug, they say, because the alternative is the loss of men's lives.

For the same length of time, the activists have boiled with anger at what they see as media bias against the drug. They reserve a special hatred for Matt Herper of Forbes, whose reporting has been consistently skeptical of the tortured path to FDA approval that Dendreon has trodden.

That's one reason why Dendreon CEO Mitchell H. Gold stuck this statement into his press release yesterday:

"We are immensely grateful to our clinical investigators and the more than 1,000 men with advanced prostate cancer who have participated in our studies over the last decade and whose courage and contribution have significantly advanced the understanding and treatment of prostate cancer and the potential role of cancer immunotherapies."

Such statements usually focus on the stats, not encomiums to the patients in the study.

Here are the hurdles that Dendreon still needs to cross:

Details on April 28 at the American Urological Association's Annual Meeting in Chicago: Tuesday's Dendreon release didn't answer important questions such as how long survival is increased.

A second Phase 3 study: As Pharmawire points out, the FDA is likely to want to see the IMPACT results repeated in order to be sure they are not a fluke:

The only Phase III trial that has [overall survival] as an endpoint is the IMPACT trial, and nothing will settle the question of whether the results can be reproduced, unless another well controlled Phase III trial is conducted.

FDA scrutiny: The FDA will be examining the data closely because of the way that Dendreon got the drug into Phase 3 in the first place -- two Phase 2 trials failed and successful results only emerged when the data from both failed trials were pooled and analyzed retrospectively. The FDA generally doesn't like such retrospective fishing.

The FDA may also want to ask why the IMPACT results were partially unblinded half way through, back in October, an event that some scientists regard as compromising the integrity of the trial. The analysts: Wall Street was mostly wrong on IMPACT, betting that the results, like the midtrial assessment, would be unspectacular. Reuters:

Not one of seven analysts who published a rating on Dendreon's stock recommended buying it ahead of the release of positive results on the prostate cancer vaccine Provenge...

Many analysts are still skeptical, refusing to upgrade their ratings to buy.

The shorts: Some people just have a financial interest in Provenge going belly-up. The WSJ:

Dendreon shares were shorted at an average price of $9.70 a share, meaning shorts are down more than $150 million [on yesterday's news].

... The most noted bear, Brean Murray analyst Jonathan Aschoff, reiterated Tuesday his $1 price target and sell rating on the stock.

Reimbursers: In many ways, this is the worst-case scenario for Dendreon. Even if the FDA approves the drug, what happens if it is so expensive that insurers decline to cover it? Or if its benefits are so marginal that it doesn't pass cost-benefit analyses? The drug could become a financial orphan -- used occasionally by the rich but largely marginal to general prostate cancer treatment.

• See previous coverage of Dendreon:
• Dendreon: Pro-Provenge Activists Heap Abuse on Cancer Drug's Critics
• Vultures Circle Dendreon Even Though Jury Is Still Out on Provenge