Dendreon Immune-Booster for Prostate Cancer Extends Survival 4.1 Months

[[Updated with analyst comment 2:25 pm Eastern]] Dendreon’s immune-stimulating therapy for prostate cancer, called Provenge, was able to improve median survival time by 4.1 months, and lowered the risk of death by 22.5 percent, according to long-awaited clinical trial results presented today. Side effects were consistent with previous trials, involving fever and chills that lasted for a couple days after injections.

The findings came from a study of 512 men, called Impact, and the announcement was made today at the American Urological Association’s annual meeting in Chicago. Dendreon (NASDAQ: DNDN) management is planning a conference call and webcast for 5:30 pm Eastern time//2:30 pm Pacific to discuss the findings in detail with the investment community.

CEO Mitchell Gold advised investors a couple weeks ago that the data was “unambiguous” and consistent with previous studies. Today’s key statistical figure, the so-called p-value, supported this comment with a reading of 0.032. That meets the FDA’s threshold for confidence that the finding wasn’t a statistical fluke. The results are also consistent with a previous trial of 127 men, called 9901, which showed that Provenge was able to boost survival by a median time of 4.5 months. Dendreon tried to win approval from the FDA to market the drug based on that earlier data, but the agency said it needed more proof from this ongoing study first.

“These results confirm the clinical value of Provenge to prolong survival in patients with advanced prostate cancer. Moreover, it validates the longstanding but elusive aspiration to harness a patient’s own immune system to fight cancer,” said Philip Kantoff, head of the prostate cancer program and chief of the division of solid tumor oncology at the Dana-Farber Cancer Institute and Harvard Medical School and a principal investigator of the IMPACT study, in a Dendreon statement.

“Today’s results confirm the potential for Provenge in prostate cancer and validate the potential of our pipeline of active cellular immunotherapy product candidates that may help patients who are diagnosed with other cancers,” said Mitchell Gold, Dendreon’s CEO, in a statement.

The data from the Impact study showed that men who were randomly assigned to get Provenge lived a median time of 25.8 months, compared with 21.7 months for those who got a placebo treatment. After three years of follow-up, almost one-third of Provenge patients (31.7 percent) were still alive, compared with almost one-fourth of placebo patients (23 percent).

As a reminder, Dendreon has worked for years to develop its active immunotherapy, or cancer vaccine, technology. It doesn’t work like a traditional chemotherapy, or even a targeted antibody drug that’s supposed to seek out cancer cells and spare healthy ones. Instead, Provenge is designed to trigger the body’s natural immune defenses to recognize cancer cells as foreign invaders, like a virus, and kill them.

Dendreon’s approach requires blood to be drawn from a patient, and some white blood cells vital to the immune system, called dendritic cells, to be separated in a lab. The cells are shipped to the company and incubated with a genetically engineered protein found on prostate cancer cells, called PAP. This process is supposed to “teach” the immune system to recognize cells with this marker as foreign and fight them, and is sort of like waving a red flag in front of a bull. These newly revved-up white blood cells are shipped back in cold storage from the Dendreon factory to the clinic, and re-infused into the patient, giving them new ability to fight off the cancer.

Dendreon, founded in 1992, has spent more than $560 million in investors’ money to build up this amount of evidence to support Provenge as a new treatment for prostate cancer. About 30,000 men die of the disease each year in the U.S. Dendreon has said it plans to incorporate the new findings into an amended FDA application, which it hopes to turn in during the fourth quarter of this year, in hopes it can start selling Provenge as its first marketed product in 2010.

Shares of Dendreon surged 14 percent earlier in the day in anticipation of the news, then crashed by 45 percent until trading was halted at 1:27 pm Eastern time, about a half-hour before the announcement. Dendreon’s last trade was at $11.81 before the announcement.

“Given these data, we see absolutely no reason why Provenge should not receive approval from the FDA,” said David Miller, CEO of Biotech Stock Research, in a note to clients. In referring to the fast drop in shares, he added: “We have no idea what the hell that’s about, because the data are clearly good.” Earlier in the day on CNBC, Miller said any improvement in median survival time of more than 4 months will be considered a “home run.”

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6 responses to “Dendreon Immune-Booster for Prostate Cancer Extends Survival 4.1 Months”

  1. Bob says:

    “median survival time of more than 4 months will be considered a “home run”… sounds like your garden-variety stock analyst. Xconomy did not include any caveat whether Mr. Miller owns Dendreon stock…

    We need better outcomes measures and metrics. 4.1 survival increase months over a 5 or 10 year disease? and at what cost?

    p-values of 0.05 and below are better… 0.032 is still in the gray-zone of statistical significance that placebo is sufficiently different from Provenge.

    The 0.032 value with a *lower* survival rate increase than the previous study (median 4.1 months to 4.5 months) makes this result-set stay on the fence.