Dendreon Immune Booster for Prostate Cancer Helps Men Live Longer; Shares Boom

4/14/09Follow @xconomy

[[Updated]] Dendreon has been vindicated. The Seattle biotech company, after living through years of controversy about whether its experimental drug helps prostate cancer patients live longer, said today that a clinical trial of 512 men now shows that the treatment can help prolong life with minimal side effects. Shares skyrocketed by more than $12, rising above $20 a share after the opening bell.

The trial, called Impact, randomly assigned men to get either the company’s experimental immune-boosting therapy, Provenge, or a placebo. The study found that men who took Provenge had a lower risk of death than those in the control group—the company needed to show at least a 22 percent improvement on that measure. Side effects were consistent with what was seen in previous trials—fever and chills that lasted a couple days. Dendreon (NASDAQ: DNDN) will now pull together this new information to update its application with the FDA in the fourth quarter, in the hopes of bringing this new drug to the U.S. market. Full data are expected to be announced at 2:20 pm Central time on April 28 at the American Urological Association meeting in Chicago.

The finding is a watershed moment for the field of cancer immunotherapy, sometimes called cancer vaccines, in which researchers try to stimulate the immune system to fight cancer cells like a virus. If Dendreon can win FDA approval, it will be the first company in this field to do so, after a long list of failures from the past couple of years, at companies like Cell Genesys, Favrille, and Genitope. Dendreon’s new drug will offer a new treatment option for about 30,000 men who die in the U.S. each year from prostate cancer, beyond the standard hormone deprivation and chemotherapy, which have side effects many men want to avoid. It is also a breakthrough moment for the Seattle biotech cluster and for Dendreon. The company was founded in 1992, has spent more than $560 million of investors’ money on R&D, and hopes to make Provenge its first marketed product in the U.S.

“Today is a historic day for patients, our industry, the scientific community, and certainly for Dendreon,” said CEO Mitchell Gold, on a conference call this morning with analysts. In a statement, he added, “The successful outcome from the Phase 3 Impact study provides validation of the long-pursued goal of harnessing the human immune system against a patient’s own cancer.”

Dendreon didn’t provide specifics about the trial outcome in today’s release, such as the magnitude of the survival benefit, or the degree of statistical significance of the finding, which measures how confident statisticians are that the finding isn’t a fluke.

Dendreon offered a few hints about how strong the result was on the conference call this morning. Provenge’s ability to prolong lives for patients was “consistent” with previous trials, and so was the side effect profile, Gold says. (An earlier trial of 127 men showed a median benefit of 4.5 months of extra survival time.) When researchers dug deeper into various subpopulations of patients with less aggressive and more aggressive tumor types, and filtered patients based on other characteristics that might have biased the result, Dendreon still saw an across the board benefit, Gold said.

“The results are unambiguous,” Gold said. “It was a clear hit on the pre-specified endpoint of overall survival.”

The positive finding has multiple implications for Dendreon’s business. It will plan to commercialize the drug by itself in the U.S., building a sales team of about 100 representatives to call on urologists and oncologists, Gold said. It will seek a partner to help commercialize the drug in Europe, he said. Dendreon will wrap up some final remaining questions FDA has about its manufacturing processes at a factory in New Jersey, and get ready to start pumping out commercial product after the FDA completes its six-month review of the company’s amended application. The renewed excitement for its technology, and the support from investors, means that Dendreon will now dust off its ideas for applying it to other forms of cancer, like breast, colon, bladder, and kidney tumors, Gold said. The company plans to discuss those plans in greater detail at an analyst meeting in the summer, he said.

The company hasn’t disclosed what Provenge’s price will be, but it has said in the past that it will be comparable to other biotech drugs, meaning it will likely be tens of thousands of dollars per patient.

Gold had some philosophical moments on the conference call, as he took time to thank the company’s investors for supporting the many years of development for Provenge. “Today reminds us how the U.S. biotech industry can continue to innovate,” he said. “It could not have occurred without access to capital. Exploring new frontiers in medicine is costly and risky.”

As a reminder, Dendreon has worked all those years to develop its active immunotherapy, or cancer vaccine, technology. It doesn’t work like a traditional chemotherapy 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 has generated loads of drama and controversy in its history. Many scientists thought its first bid for FDA approval in 2007 was premature on the basis of a study of 127 men, yet the company passed muster of an expert advisory committee by a 13-4 vote. Then the company was stunned when the FDA rejected the advice of its own committee in May 2007, saying it wanted to first see the results of this ongoing study of more than 500 men. You can read more about the whole saga in this recap we published on April 3.

Many investors have been betting, and hoping, that Dendreon would fail again. More than 19 million shares out of Dendreon’s 98 million shares outstanding were held in a short position at the end of March, according to Nasdaq data. Gold resisted whatever urge he might have for an in-your-face comment to his critics, but he took the opportunity make some very lofty comments.

“The most meaningful science is often the most controversial,” Gold said. He added, “It is my personal hope this will demonstrate the diagnosis of cancer is not hopeless.”

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