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Review looms for cancer vaccine Government's documents, analysts, short-sellers cast cloud over Dendreon's experimental prostate cancer treatment. By Aaron Smith, CNNMoney.com staff writer March 28 2007: 2:14 PM EDT
NEW YORK (CNNMoney.com) -- Provenge, an experimental prostate cancer treatment from the drug company Dendreon, could have a rough time winning over Food and Drug Administration advisors on Thursday, analysts say. A panel of FDA experts is expected to vote on whether they consider Provenge good enough for the agency's approval. The result of this vote is taken as advice by the FDA at a later time, when it decides whether to approve the treatment. But some analysts are concerned about what they've read in FDA documents, which seem to demonstrate a negative sentiment towards the drug. Provenge is an experimental vaccine that would be used as a treatment rather than a preventative like most other vaccines. FDA documents note that two late-stage studies of the vaccine failed to meet their goals in slowing the progression of prostate cancer. There has been some indication that the drug might increase survival time, but the FDA documents said it was hard to determine whether that was the result of chance or if the drug had demonstrable success against prostate cancer. About one-fourth of investors holding Dendreon (up $0.53 to $5.15, Charts ) stock have cast a black cloud over the company by selling the stock short. "I don't think this vaccine gets approved ever," said Jonathan Aschoff, analyst for Brean, Murray, Carret & Co., who rates the company a "sell." Aschoff projects that the stock price will be "cut in half" following a negative vote from FDA analysts. Aschoff said he is particularly concerned about the incidence of strokes in Provenge patients during late-stage trials. Another analyst, Maged Shenouda of UBS, referred to these strokes as "a potential safety signal" and therefore reason for concern. "Given these comments [from the FDA documents,] as well as our view that Provenge lacks compelling efficacy evidence, we continue to believe that the FDA will require additional trial data before final approval," wrote Shenouda in a published note. But Thomas Farrington, a prostate cancer survivor as well as president and founder of the Prostate Health Education Network, hopes that the FDA approves Provenge because of the data showing that it might prolong survival. Farrington, who plans to speak on behalf of the vaccine at the FDA panel, also supports Provenge because it would be a new type of immunotherapy - a vaccine used as a cancer treatment - which might lead to other types of treatment. I certainly hope the FDA sees the wisdom of this drug as a potential break-through," said Farrington. "Immunotherapy might be the magic bullet for which we're hopeful." Seattle-based Dendreon is a biotech, an area of drug development that is heavily involved in cancer treatments. Amgen (down $0.18 to $56.03, Charts ) and Genentech (down $0.39 to $82.16, Charts ), the two biggest biotechs in the world, are also focused on cancer treatments. A Dendreon spokesman did not return a phone message this morning. Companies generally don't comment prior to FDA advisory votes. The analysts quoted in this story do not own shares of company stocks mentioned here, though UBS and Brean, Murray, Carret & Co. make a market in Dendreon.
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Update 03/28:
A Radical Attack On Prostate Cancer
Matthew Herper , 03.28.07, 11:45 AM ET Seattle-based biotech Dendreon is hoping to get U.S. approval for the first cancer drug that would train the body to fight off cancer on its own, with few side effects. But researchers, statisticians and Wall Street analysts are fiercely debating whether there is enough data about this radical new treatment. Dendreon's (nasdaq: DNDN - news - people ) Provenge is a so-called cancer vaccine. Researchers prefer the term immunotherapy because it would treat, not prevent, cancer. A personalized drug, composed of human immune system cells, is created for each patient; the idea is to give the immune system the tools it needs to fight off the disease. On Thursday, a panel of experts convened by the Food and Drug Administration will debate whether the drug is ready to be marketed. The FDA often follows the recommendation of such panels, but it doesn't have to. Already, briefing documents have been posted saying that the drug seems very safe--although there is a worry of stroke--and reviewing the arguments about whether or not it is effective at prolonging patients' lives. Why is there any question at all? When researchers run a clinical study, they define a specific goal. For instance, that drug will extend life over a prespecified time or prevent tumors from growing compared to a placebo. The whole study is designed around this goal. If the trial falls short, its results can only be used to generate new questions, not to draw scientific conclusions. Provenge has failed in both of its main studies--but it seems to help patients live longer. The clinical trials tested the drug in a relatively small number of cases, with only 127 men in the main study who showed a benefit. But survival was extended four months for patients with metastatic prostate cancer. Statistical rules aside, Provenge fans say, survival is awfully hard to fake, and desperate metastatic prostate cancer patients who would get Provenge have only one drug, the chemotherapy Taxotere, at their disposal. The Taxotere drug, made by Sanofi-Aventis (nyse: SNY - news - people ), has many unpleasant and dangerous side effects. The data has convinced some who were skeptical that Provenge may have merit. Philip Kantoff, a urological oncologist at Harvard Medical School and the Dana Farber Cancer Institute, is conducting a big clinical trial that should firmly establish whether and how much Provenge helps patients. He has consulted with Dendreon. For a long time, he was one of Provenge's doubters. "I thought the concept was too simplistic for belief," Kantoff says. "I didn't think it had a snowball's chance in hell of working." But the data showing the drug increases survival has made him cautiously optimistic. "I'm still skeptical, but I think there's something going on here," he says. His doubts rest mainly on the fact that results were small. "If this were a much larger study, to me this would be a slam dunk." Kantoff says that if the drug were approved, he would probably prescribe it. So far Provenge seems mostly to cause flu-like symptoms, but FDA reviewers note there may also be an increased risk of stroke. If the medicine is fairly safe and might be effective, why not offer it to patients? David Penson, a urologist at USC's Keck School of Medicine, has also gone from being a doubter to an investigator in a Provenge clinical trial and a consultant for Dendreon (he says he has received less than $10,000 in fees). "When they first released their data, they had to massage some data to show a clinical difference," he says. Dendreon's first study showed efficacy only in less-sick patients. Colleagues convinced Penson to give Provenge a try in clinical trials, and he was impressed. He remembers one patient, a doctor, who went from being wasted and fatigued from his metastatic prostate cancer to being able to play golf again. Patients don't care if a drug meets the original primary endpoint of Dendreon's study, an improvement in X-rays, says Penson. "All they care about is living longer." This is the argument at the heart of the case for Provenge. Neal Shore, medical director of the Carolina Research Center, says rejecting Provenge now would be "grossly unfair to the patients who have no other options but to enter clinical trials." Shore argues that "a lot of people will end up dying" before bigger clinical trials could show a benefit. But there are other issues at play. Once a drug is approved, other medicines can get on the market by proving they are better. If an ineffective drug slips through, that could open the door to other less effective medicines. Another worry is that the benefit of Provenge might be real but less robust than it appears. Because larger issues are at play, this is exactly the kind of situation in which the FDA might go against the decision of an advisory panel. Even if Dendreon has a great day on Thursday, the company won't be home free.
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Update 03/28:
FDA Questions Dendreon Vaccine
Tuesday March 27, 4:55 pm ET FDA Documents Raise Questions About Dendreon's Evidence in Support of Prostate Cancer Vaccine WASHINGTON (AP) -- Federal drug regulators on Tuesday released documents that raise questions about the effectiveness of Dendreon Corp.'s experimental prostate cancer vaccine. The Food and Drug Administration posted briefing documents on Dendreon's Provenge to its Web site ahead of a Thursday meeting at which outside experts will vote on the safety and effectiveness of the vaccine. FDA is not required to follow the panel's recommendations, though it often does. Dendreon's main evidence for the effectiveness of Provenge is a study showing that men with prostate cancer who received the vaccine lived about four and a half months longer than those who did not. However, the FDA said this study, and another conducted by Dendreon, failed to meet certain effectiveness targets. Agency staff also said, though, that the two studies taken together provide some evidence to support use of the vaccine. The agency plans to ask the outside experts to discuss the persuasiveness of the company's data. Shares of Dendreon Corp. rose 8 cents, or 1.8 percent, to close at $4.62 on the Nasdaq Stock Market.
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Update 03/30:
March 29, 2007, 5:05 pm Experts Favor Dendreon’s Cancer Vaccine Posted by Jacob Goldstein An FDA advisory committee just voted in favor of Provenge, the experimental vaccine developed by Dendreon , the Seattle-based biotech company, to treat advanced prostate cancer. The case was something of a nail-biter — Dendreon’s stock surged 40% this week, despite the publication on Wednesday of FDA documents that showed Provenge failed to meet the endpoints in two clinical studies (most importantly, the drug did not slow the spread of cancer in patients). But the agency did note that the studies suggested the drug extended life by about four months. The panel voted unanimously that the treatment was safe. The FDA had also asked the panel to vote on whether it was effective. But the panel was apparently uncomfortable answering that question, because the trials of the drug failed to show effectiveness, but did appear to extend life, according to Jennifer Corbett-Dooren, who covered the meeting for Dow Jones. So the panel, in what seems an odd parsing of words, decided instead to vote on whether there was “substantial evidence” of the drug’s efficacy — a vote that went 13-4 in favor of the drug. The panel also said the company needs to complete a larger study of the therapeutic vaccine, which has already begun. The FDA is not bound by the vote, but it usually follows the advice of its committees.
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Update 03/30:
March 30, 2007, 4:21 pm Q&A: Dendreon’s Vaccine for Prostate Cancer Patients Posted by Jacob Goldstein An FDA advisory committee yesterday voted 13-4 in favor of Provenge, an experimental treatment for advanced prostate cancer. The vote was hotly anticipated by cancer patients and investors in Dendreon, the Seattle-based biotech company whose future is pegged to Provenge. Shares in the company rose more than 100% today. Provenge commands special attention because it’s a vaccine, derived from a patient’s own cells, that mobilizes the immune system to attack cancer. But what would Provenge mean for men with prostate cancer? To find out, we called Simon Hall , director of the Deane Prostate Health and Research center at the Mount Sinai School of Medicine in New York, and an investigator on a trial of Provenge. (Hall told the Health Blog he has no financial ties to Dendreon.) Here are the highlights of our conversation. Q: If the FDA approves Provenge, how would it fit in with current treatment ?
A: The vast majority of patients are diagnosed with localized disease, which is treated with surgery or radiation. About a third of those patients will have a recurrence — if they live long enough, they’ll have metastatic disease and have hormone treatment. For the vast majority of those patients, that will buy them several years where their disease is under control. But then the cells will adapt and start to grow anyway. I would estimate between 29,000 and 40,000 men are in this boat. The only treatment that has ever been shown to have any advantage for these patients was taxotere [a chemotherapy drug from Sanofi-Aventis], shown to extend life by 3 months. But the bottom line is patients don’t want chemotherapy. The reality will be that when the patients get to this point, they’re probably going to do the vaccine. I think there will be a huge demand. I’ve had a lot of my own patients calling me and saying, “Can I get the vaccine?” Q: Any idea how much Provenge will cost? Will the price influence who gets it?
A: It’s going to be a very expensive, boutique-type agent. Different from drugs or even vaccines that are in the pipeline, this one is custom made for each individual patient with their own cells. A lot of times we use drugs off label; I don’t think it will happen in this case because of the expense. The rumor is it will cost $20,000 per infusion. And the way the trials have been done, it’s been three infusions per patient. Q: The clinical studies failed to meet their goals, but suggested the vaccine prolongs survival for four months. Is that significant?
A: You set up a study and you say my primary endpoint is time to progression, and my secondary endpoint is delaying time to pain. They failed on that. They were disappointed, and I’m sure they had statisticians come in and say, “How can we carve up the data and get something out of the study? And they were like, “Holy cow, at 36 months, only 10% of those on placebo were still alive, but you’ve got a third of those on Provenge still alive.” Q: Do you think the FDA will follow the committee’s advice?
It’s hard to guess. Would they approve a drug based on one very small study that was sort of done backwards? A committee looks at it and votes 13-4 to approve. I don’t know what they will do. Will they approve? Or will they say, “Listen, you’ve got this other big study that’s going on and maybe we should wait a year and see what that says.” Q: What’s the bottom line for Provenge?
We need it. There’s little toxicity. If the larger study validates the first study, or clinical experience validates it, it will be a step forward for men with prostate cancer, and for this whole idea of using the immune system to fight cancer. Bonus: We’d been wondering all week how to say “Provenge.” Like revenge? Or French-style, like melange? Hall says it’s like revenge, but the accent is on the first syllable — PROvenge.
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DNDN:
This call was made
on 03/28/07
@ $5.14
| Rating: |
$5.14 (03/28/07)
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| Closed: |
04/12/2007
@ $16.96
(-229.96%
in
15 days)
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| Target: |
$4.00
(-22.18%)
in Three months
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Agree
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