Dendreon stock dropped 27 percent yesterday on frenzied trading after the company released a confusing batch of clinical findings for its experimental prostate-cancer drug, Provenge...

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Dendreon stock dropped 27 percent yesterday on frenzied trading after the company released a confusing batch of clinical findings for its experimental prostate-cancer drug, Provenge.

The news was unsettling for Dendreon and cancer patients tracking the drug’s progress. One year ago, the Seattle company made a national splash when it showed its next-generation prostate-cancer fighter could extend patients’ lives longer than any other drug, with minimal side effects.

At first glance, yesterday’s news clearly dampened that enthusiasm. The biotech company said that in a 98-patient trial, it was unable to show Provenge could reach its primary goal of significantly slowing prostate cancer.

What alarmed investors more, though, was that the failure spanned all varieties of patients, including ones with moderate-to-slow-growing tumors. That subset had been expected to benefit, because such patients benefited in an earlier study.

On the flip side, Dendreon said the results confirmed an important earlier finding. A follow-up analysis of the trial after 30 months confirmed Provenge was able to extend lives.

Dendreon would not, however, release detailed statistics to back up that assertion.


Located: Seattle

CEO: Mitchell Gold

Employees: 220

Lead drug candidate: Provenge, for prostate cancer

And it did not explain the apparent contradiction between extending life and the inability to slow progress of the disease.

The company said it prefers to release more details at a medical meeting, where they can have a larger impact.

Dendreon Chief Executive Mitchell Gold tried to downplay the failure, while accentuating Provenge’s survival edge.

“Survival is the most meaningful [goal],” he said in a phone interview before a presentation yesterday to investors at the JP Morgan Healthcare conference in San Francisco.

Several people with experience analyzing biotech stocks were bewildered. It’s uncommon for a drug to fail to slow a disease yet prolong lives.

“Today’s news certainly adds complexity,” said Mark Monane of Needham & Co.

“People are confused, and they want answers,” said David Miller of Biotech Monthly, a Seattle-based trade publication.

“It’s a head-scratcher,” said Paul Latta of McAdams Wright Ragen.

Some investors actually had forgotten the trial at issue, because it was halted in 2002.

The trial was stopped because Dendreon believed it would have a better chance to succeed with a fresh trial focused solely on the subset of patients who were benefiting from the drug. It began a 275-patient trial, which is currently enrolling only those type of patients.

Because the stopped trial had enrolled some of the sickest patients, it wasn’t necessarily expected to reach the main goal of slowing the disease.

But some analysts were alarmed it was unable to confirm what has become an article of faith — that Provenge slows the disease in patients who are less sick.

Provenge could be in trouble if it can’t slow the disease in those patients. Monane, an analyst who downgraded Dendreon from “strong buy” to “buy” yesterday, said in a report he’s worried the ongoing trial might not succeed after all.

“We believe the clinical-trial risk associated with the ongoing trial has increased,” he wrote.

Dr. John Corman, a prostate-cancer specialist at Virginia Mason Medical Center in Seattle who has participated in the Provenge trials, said the results were confusing, but that he believes survival is the most meaningful clinical goal.

Corman said he’ll remain an advocate of Provenge as long as it appears to extend lives.

Monique Greer, a Dendreon spokeswoman, said that even if Provenge is unable to slow the disease in the ongoing trial, it could still win regulatory approval if it delays onset of disease-related pain or extends survival.

Miller, who owns shares in Dendreon, said the company could rebound next month when it presents a more detailed picture of Provenge’s survival edge at a medical meeting.

Later in the year, when the final 36-month survival analysis of the 98-patient trial ripens, the company could have a stronger case for Provenge being approved.

“I would hope that a company who has demonstrated a statistically significant survival advantage in two pivotal clinical trials for cancer would get an approval,” Miller said.

Luke Timmerman: 206-515-5644 or