FDA Panel OKs New Prostate Cancer Drug
Agency Will Consider Recommendation to Approve Provenge for Advanced Prostate Cancer
March 29, 2007 -- A new immune system treatment for advanced prostate cancer
is safe and effective enough to begin U.S. sales, a panel of FDA advisors
Many experts said they were uneasy about backing the vaccine-like treatment,
known as Provenge, because it showed only slight evidence that it prolongs the
lives of men with the disease. But most agreed to recommend approval anyway,
citing the scant options available to patients, many of whom are facing a
"I wish we all could have voted ‘maybe’ on this, but I don’t think we
can," said Farshid Guilak, PhD, a professor of surgery at Duke University
who was a member of the panel.
New Treatment Class
Dendreon Corp., the biotech firm that makes Provenge, touted the treatment
as the first cellular therapy against cancer. To undergo treatment, patients
have immune cells removed and treated with immune agents.
The cells are then reintroduced into the body with chemical programming
that, in theory, allows them to mount an immune response against cancer
Men with advanced prostate cancer often undergo hormone treatment used to
block the action of testosterone and related hormones. The treatment can cause
disturbing side effects, including breast enlargement and sexual
A pair of studies suggested Provenge may slow by one to two weeks the
progression of prostate cancer in men who have cancer that does not respond to
Men who used the treatment also showed some evidence of living longer than
those who took a placebo. In one trial, men who got active treatment lived an
average of 3.3 months longer. In another, they lived four and a half months
Experts criticized the studies for enrolling only roughly 100 to 130
patients, a relatively small number that can limit scientists' ability to
But most said they support Provenge anyway, given the limited choices for
men with advanced disease.
"If we can buy them a couple of minutes or a couple of months or a
couple of years, then it's our obligation to do that," said Robert J.
Samuels, a member of the panel who said he was diagnosed with prostate cancer
13 years ago. "We understand it’s a risk. But it’s a risk most of us are
willing to take."
Dendreon argued their studies showed the product has benefit. "Even
though small, you can take the results with a great deal of confidence,"
said Mark Froelich, the company’s vice president for clinical affairs.
The company is conducting a third study to test whether it improves survival
in more than 400 patients. Experts said the results of that trial should have a
heavy bearing on whether the FDA decides to approve Provenge.