Feuerstein's Biotech-Stock Mailbag

It's been awhile since the last Biotech Mailbag, but this week's will be devoted to Dendreon(DNDN Quote)! So warm up those keyboards, I await your hate mail. (Insert sarcastic smirk here.)

Several readers asked about Dendreon's announcement Thursday of a new data analysis that correlates the potency of the prostate cancer vaccine Provenge to overall survival.

Among those was Don. B, who asks, "Do you think the study results from [Thursday] morning saying an increased potency of Provenge ... is just noise? I'm not touting or griping, I read your stuff and respect your views and your note this morning seems to have come out before Dendreon released the data."

Let's address the potency analysis first. Then, I'll recap what I wrote Thursday on our subscription site RealMoney, for those who couldn't read it. That dealt with Congressional hearings on Provenge and the Food and Drug Administration.

I don't think Thursday's study results are noise, but I also don't see the data as new or very compelling, especially for those trying to handicap the interim data analysis expected later this year from the ongoing Provenge phase III study.

I know anything related to Dendreon makes for a good headline -- and gets the momentum traders excited -- but it doesn't take much Googling to easily show that Dendreon has been down this path before.

Take a look at Thursday's press release, titled "Dendreon Presents Data Correlating the Cumulative Potency of Provenge to Overall Survival." Then, compare it to a press release issued by the company on Oct. 27, 2006.

That announcement was titled "Dendreon Presents New Data Correlating Potency of Provenge to Survival in Phase 3 Studies."

Sounds familiar, doesn't it? Read both press releases and you'll be hard-pressed to see much difference. Note that the older announcement was issued before Provenge was filed with the FDA, before the March 2007 advisory panel, and obviously, before the FDA decided against approving Provenge.

It didn't matter much then, and I doubt it will matter much today.

That's because both data analyses somewhat state the obvious: The potency of Provenge, i.e., the vaccine's ability to train the patient's immune system to recognize and kill prostate cancer cells, has a direct impact on the patient's response. In this case, that response is overall survival.

In other words, this analysis tells us something important about the manufacturing of Provenge, but it doesn't really provide an early signal for how well a patient will ultimately respond to the vaccine.

When Dendreon makes Provenge for prostate cancer patients, the company tests the strength of the vaccine by measuring increases in a molecule called CD54. Proper "upregulation" of CD54 tells Dendreon that a batch of Provenge just made is potent and ready to be administered to patients.

This is an important quality-control step in how Provenge is made, and it's one reason why the FDA hasn't really had any significant issues with Dendreon related to the manufacturing or potency of the vaccine.

The data analysis announced Thursday -- and the one released back in October 2006 -- confirm that Provenge must be potent (measured by CD54 upregulation or by another test looking at total nucleated cells, or TNCs) in order for prostate cancer patients to benefit by increased survival.

What these analyses can't predict is which patients will survive longer, or how long they will survive. So there's little value here in terms of trying to predict the outcome of the ongoing IMPACT trial, which will give us a definitive answer about Provenge's efficacy. Interim results from this phase III study are expected in the second half of this year.

1 What would best describe your stance heading into the coming week of trading? Bullish Bearish Neutral 2 Which of these sectors do you think is set to move up in the coming week? --Choose One--Aerospace and DefenseAirlinesAutomobilesBeverages and Food ProductsBiotechnologyCommercial BanksComputers and PeripheralsConsumer NondurablesEnergy Equipment & ServicesHMOs and HospitalsHomebuildingInsuranceIntegrated OilInternet, Software ServicesInvestment Bankers and BrokersMediaMultiline RetailPharmaceuticalsPrecious MetalsSemis, Semi EquipmentTelecom EquipmentTobacco and AlcoholWireless CommunicationsUtilities 3 Which of these sectors do you think is set to move down in the coming week? --Choose One--Aerospace and DefenseAirlinesAutomobilesBeverages and Food ProductsBiotechnologyCommercial BanksComputers and PeripheralsConsumer NondurablesEnergy Equipment & ServicesHMOs and HospitalsHomebuildingInsuranceIntegrated OilInternet, Software ServicesInvestment Bankers and BrokersMediaMultiline RetailPharmaceuticalsPrecious MetalsSemis, Semi EquipmentTelecom EquipmentTobacco and AlcoholWireless CommunicationsUtilities View the results without voting