It appears as though Dendreon put out some long-awaited good news on the Provenge therapeutic prostate cancer vaccine.
The vaccine intended for men with advanced prostate cancer “met” its primary endpoint of overall survival in the 512-patient IMPACT study, according to the company. The primary endpoint was a 22% reduction in risk of death compared to placebo, according to previous disclosures.
“The magnitude of the survival difference observed in the intent to treat population resulted in the study successfully achieving the pre-specified level of statistical significance defined by the study's design,” the company said in a statement.
“Survival is the gold standard outcome for oncology clinical trials, and overall survival was the primary endpoint of the IMPACT trial. The positive results from this landmark study provide confirmatory evidence demonstrating that treatment with PROVENGE may prolong survival,” according to Dendreon CEO Mitchell Gold.
That’s essentially all the public will get until April 28 when the full study is released at the American Urological Association meeting in Chicago.
Despite the lack of real clarity, investors made some big bets on the results. Volume went from 12,775,310 shares on April 13 to 65,410,443 shares at close on April 14. The stock went from $7.30 a share to $16.99—and reached a high of $22.10—over the same period, according to Google Finance.
Based on our conversations over time with a number of people familiar with this therapy, we’re withholding judgment on the approvability of Provenge until the full results are out and we can understand why a drug that missed it’s primary endpoint twice, hit it a third time.
Let’s just say the burden of proof on Dendreon will be quite high.
Provenge represents the first in a new class of active cellular immunotherapies that “engage the patient's own immune system against cancer,” in the company’s own words.
Dendreon says that because the study results meet the criteria of a special protocol assessment agreement with FDA, the company will file an amended BLA in the last three months of the year to gain market approval.
“The successful outcome from the Phase 3 IMPACT study provides validation of the long-pursued goal of harnessing the human immune system against a patient’s own cancer,” Gold said in the statement.
It’s statements like this from company CEOs of high profile therapies that always raise a red flag to us. We’ve seen and heard far too many stories that are similar to Provenge where a combination of hopes and dreams and fevered market speculation can sometimes lead in exactly the wrong direction. Those experiences are cause for caution when trying to bet on FDA approval of the cancer vaccine.
Remember, in October 2008, the IMPACT study interim results showed the vaccine failed to meet the primary endpoint of overall survival—Provenge demonstrated a 20% reduction in risk of death but was short of the 22% mark.
If after the details of the study and the data are released, and the results are compelling, it will be a great victory for Dendreon, its CEO Gold, and a motivated and mobilized patient advocacy community intent on seeing the therapeutic vaccine get to market.
But we’ll have to wait until April 28 at least. In reality, we’ll have to wait for FDA to comb through the data before we know for sure. And until then, we’re managing expectations.
