Prostate Cancer Vaccine Meets Goal

April 14, 2009 -- Provenge, an experimental treatment vaccine for advanced prostate cancer, met researchers' goal in a key trial needed for FDA approval.

That news comes from Dendreon, the company that makes Provenge.

"We believe this is truly a breakthrough for the prostate cancer community and a testament to the promise of the field of cancer immunotherapies," Dendreon's president and chief executive officer Mitchell Gold, MD, said in a conference call today.

Provenge is a biologic drug given by infusion to spur the immune system to fight advanced prostate cancer that doesn't respond to anti-androgen treatment.

In 2007, an FDA advisory panel recommended that the FDA approve Provenge. But instead, the FDA requested more information about whether Provenge prolongs survival.

That request led to a new study of 512 men with advanced prostate cancer. Those men had metastatic, androgen-independent prostate cancer, meaning their cancer had spread and wasn't responding to anti-androgen treatment.

In that study, overall survival was significantly better for men taking Provenge than those taking a placebo.

The study's results were "unambiguous" and "very consistent" with previous Provenge trials, Gold says.

Dendreon plans to submit the study's results to the FDA in the fourth quarter of 2009; after that, the FDA will have six months to review the material, Gold says.

"This data supports Provenge being used as front-line treatment in men with metastatic, androgen-independent prostate cancer," says Gold, who notes that no new side effects from Provenge stood out in the study. In previous trials, the most common side effects in men taking Provenge were chills, fever, headache, fatigue, shortness of breath, vomiting, and tremor, mainly at a low level and for one to two days following infusion.

Gold says that those men would first have surgery or some form of local therapy, then anti-androgen therapy if their cancer recurred, and if their PSA levels rose after that, "Provenge would come into play as a potential treatment option for them."

In men with prostate cancer, PSA (prostate-specific androgen) levels are used to gauge the success of prostate cancer treatment.

Dendreon isn't releasing any further details of the study until April 28, when the findings will be presented at the American Urological Association's annual meeting in Chicago.

The technology used to make Provenge may also prove useful against other forms of cancer, Gold says.

American Cancer Society Responds

The American Cancer Society released a statement about today's Provenge news. The statement comes from Otis W. Brawley, MD, chief medical officer at the American Cancer Society.

Dendreon's announcement about the new Provenge study "is reason for optimism about a vaccine that has generated controversy for several years," Brawley says. "We have to respect the scientific process, an important part of which is a full disclosure and careful review and discussion of the data, which the company says will not be released until an upcoming medical meeting."

"One of the most important questions we'll be looking at will be the magnitude of the survival advantage; how much longer the men taking the vaccine lived compared to those on standard therapy," Brawley continues. "As with any new therapy, it will take a detailed analysis to fully understand the impact of this potential new treatment for patients with advanced prostate cancer. We look forward to the presentation of the study at the upcoming meeting."