Dendreon prostate-cancer therapy shown to extend patients' survival time
An experimental therapy for prostate cancer extends patients' median survival time by 4.1 months, Seattle biotech firm Dendreon announced Tuesday.
Seattle Times business reporter
It's a small step in curing cancer but a giant leap for a new approach: harnessing the body's own immune system to fight the disease.
An experimental therapy for prostate cancer successfully used that paradigm to extend patients' median survival time by 4.1 months, Seattle biotech firm Dendreon announced Tuesday. After three years, 31.7 percent of the patients receiving the therapy were still alive, compared with 23 percent of those on a placebo.
Results of the 512-person clinical trial for Dendreon's therapy, Provenge, confirmed the findings of a smaller test by prolonging survival without major side effects, the company reported at the American Urological Association annual meeting in Chicago.
"We're really thrilled with the data we have in hand, and it's something we're really looking forward to bringing to patients," said Dendreon CEO Mitchell Gold.
The latest research is important because "for the first time we're seeing a response that shows a survival benefit," said Dr. John Corman, medical director at the Virginia Mason Cancer Institute in Seattle and one of the study's principal investigators. "It's extremely exciting. It's only the first step but a big first step."
For Dendreon, it was a major milestone in a long and bumpy road toward getting the treatment approved by the U.S. Food and Drug Administration.
Patients enrolled in the trial had an advanced form of the disease that proved resistant to other therapy.
Dendreon said side effects in Provenge patients were "chills, fever, and headache," but those symptoms "were primarily low-grade with a short duration of 1-2 days following infusion."
The results were better than the chemotherapy drug, Taxotere, that is used for patients at that stage, and immune therapy doesn't have debilitating side effects.
"The ability to give these patients both increased survival, and possibly improved quality of life, is very important," said Dr. Ira Sharlip, spokesman for the urological association.
However, the treatment did not slow progression of the cancer, which Dendreon said is difficult to measure reliably and doesn't correlate with overall survival.
And the statistics will have to undergo further scrutiny.
"If the data hold up through peer review, primarily through the FDA and the peer-journal process, it would indicate an incremental advance in the management of advanced prostate cancer," said Matthew Rettig, a medical oncologist and associate professor at UCLA's David Geffen School of Medicine.
"The main issue will be the cost of this therapy, and also generating it so that potentially thousands of patients who would want it would get it in a timely fashion," Rettig said. He was not involved in the trials.
As for cost, Gold said only that "the price point is something that will be determined in the future."
"We're fortunate that we began building a commercial-manufacturing facility several years ago in New Jersey. We'll be expanding capacity out of that facility and putting additional facilities on line to address demand."
Cost could be a big factor for insurers and governments that pay for health care.
Four months of survival "is really a fairly modest benefit," Rettig said. "Something like this in England might not even get approved by the government based on cost-benefit analysis."
But for cancer patients like Jim Kiefert, of Olympia, there was no doubt about the benefits.
"Guys in my support group are going, 'I would do that if it gave me one month of survival,' " said Kiefert, who has lived with prostate cancer for 18 years.
"If it meant my granddaughter is going to call me and say you're going to be a great-grandfather. ... Do I want to have those two or three months to see that great-granddaughter? You bet."
David Miller, CEO of Seattle-based Biotech Stock Research, said the results were better than analysts had expected. "We can't see any reason why the FDA wouldn't approve it."
Dendreon will use the new data to amend its license application with the FDA by the fourth quarter. The agency will have six months to review the data and make a decision.
Dendreon's stock started out Tuesday at $22.32. Shortly before the trial results were due to be announced, it dropped more than 45 percent before its trading was halted on the Nasdaq exchange. In after-hours trading, the stock soared to $26.17.
Miller said he did not know why the stock plunged but it may have been caused by rumors before the announcement. The stock price is up almost 400 percent since the start of 2009.
Prostate cancer strikes more than 186,000 men a year and kills more than 28,000, so there's potentially a large population who would fit the target profile of Provenge.
Using blood from a patient, Dendreon mixes white blood cells with a protein commonly found in prostate-cancer cells, aiming to activate the immune system to fight the foreign cells in an approach similar to a vaccine. The blood is then injected back into the patient.
Researchers at Dendreon and elsewhere are testing immune therapy in earlier stages of cancer. "The patient who should truly benefit is going to be a person with a completely intact immune system who doesn't have other medical problems," said Corman, of Virginia Mason.
Doctors are hoping to find a way to cure prostate cancer using a non-radiation approach, he said.
That would be "no different than you taking a mumps, measles and rubella vaccine as a child," he said. "The question is the right amount and the right time to give it."
Kristi Heim: 206-464-2718 or email@example.com
Copyright © 2009 The Seattle Times Company
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