The Impact study itself has been through a circuitous history. It was started in June 2003, and originally aimed to enroll patients with terminal prostate cancer who have moderate -to-less aggressive tumor types, as measured by a standardized “Gleason” scoring system. It was designed that way because earlier trials had suggested that Provenge didn’t work for patients with the most aggressive Gleason-rated tumors, so weeding them out would give the drug a better shot, Urdal says. The study also was primarily designed to see whether Provenge could slow down the spread of tumors, instead of waiting a longer time for data on whether it helped men live longer—the gold standard for cancer drugs.
Then in 2005, more data rolled in from the previous clinical trials suggesting that Provenge actually did extend lives, for all kinds of patients, regardless of Gleason score. So in November of that year, Dendreon agreed to an overhaul of the Impact trial, at the request of the FDA, Urdal says.
The changes were big. The new protocol called for Dendreon to enroll patients with all types of Gleason tumor scores. It switched the main goal of the study from the squishier and more debatable point of slowing tumor progression, to the more definitive measurement of survival time. It boosted total enrollment to 500 patients. And, it started allowing a slightly sicker kind of patient with bone pain into the study.
This October, then, the trial is designed to take an interim look after a certain number of deaths among the 500 men have occurred, which Dendreon hasn’t disclosed. Since it’s an early peek based on a small set of data, the analysis has to show Provenge patients are living longer than those on placebo, and demonstrate it with a higher degree of statistical certainty than normal to assure regulators that it isn’t a result of chance. If the interim analysis doesn’t clear that bar, then Dendreon expects it will have to wait for 304 patients in the trial to die, so it can do the final survival analysis.
The analogy I used in my conversation with Urdal, which he agreed is a good way to think about it, is that an interim analysis is like taking a look at the standings half way through the football season, seeing an undefeated team, and saying it looks like they will win the Super Bowl. The final analysis is confirmation that they can hoist the Vince Lombardi trophy.
Right now, Dendreon’s contract research organization is in the middle of its season. It’s double-checking patient records to make sure no mistakes are made. By October, it will have collected the data and sent it to an independent monitoring committee. That group of experts will then make a recommendation to Dendreon on whether it should declare victory now and ship off a fresh new application to the FDA, or whether it should wait for the full analysis before it sends in its application.
Urdal doesn’t sound like he’s sweating the interim analysis. If the statistics don’t show the survival benefit the company needs right away, “then we’ll just have to wait another year.”
Of course, Dendreon is naturally working on a fallback plan in case the interim analysis fails to show a clear enough survival advantage. It is developing Provenge for earlier stages of prostate cancer, and it has other drugs on the back burner designed to use the same technique for breast, kidney, and colon cancers. Another drug discovered internally, trp-p8, is being prepared to enter clinical trials, Urdal says.
So is the interim analysis really a make-or-break moment for Dendreon? Not really, says David Miller, president of Biotech Stock Research, a Seattle-based equity research firm that covers the company. “It’s clear that (CFO) Greg Schiffman has financially positioned them in a way that they won’t get in financial trouble if the interim analysis doesn’t pan out,” Miller says.
Either way, Dendreon bulls and bears are certainly going to rev up their engines between now and October in hopes they can ride the shares up past $20 again, or short them down to something a whole lot lower than its closing price yesterday of $5.69.
