April 29, 2009
Prostate Cancer Treatment Extends Patients Life
According to a report released on Tuesday, a new approach to fighting prostate cancer extended the lives of men suffering from the disease.
The treatment, Dendreon Corp's Provenge vaccine, trains the immune system to fight tumors.
Although Provenge is called a "vaccine," it treats the disease rather than preventing it.
The therapy is the first successful attempt to improve survival in late-stage testing. Doctors have been working towards this goal for decades.
"There have been a lot of false starts, but this is a real start," said Dr. Paul Schellhammer, an urologist at Eastern Virginia Medical School, and leader of the study.
Results were reported Tuesday at an American Urological Association conference in Chicago.
Dendreon paid for the study, and Schellhammer owns stock in the company.
Dendreon shares still fell 45.2 percent, despite the news.
The new therapy extended men's lives four months, one month longer than that offered by Taxotere, whose chemotherapy treatment is the only remedy for men in this situation.
Doctors hope for greater benefit if they give the drug to patients earlier in the course of their disease.
Provenge must still be approved by the federal Food and Drug Administration.
Two years ago, the FDA delayed a decision on the drug, asking for more proof of safety and effectiveness.
The new study involved 521 men suffering from cancer who were no longer responsive to standard hormone treatments.
Two-thirds of the men were given a customized treatment of Provenge, while the other third were given a dummy treatment.
To create the customized treatments, doctors collected blood cells from each patient to help their immune systems recognize cancer as a threat.
They are then mixed with a protein found on most prostate cancer cells.
The resulting "vaccine" is then given back to the patients as three installments two weeks apart.
The median survival rate was 26 months for those given Provenge, while the control group had a survival rate of 22 months.
Previous studies had raised concerns over whether Provenge caused strokes or other brain-related issues. The study found no such problems, but four men given Provenge did suffer from non-fatal lung clots.
According to Dr. Ira Sharlip, a urologist from the University of California in San Francisco and a spokesman for the urological association, improving survival "is the gold standard" for any treatment.
Dr. Otis Brawley, chief medical officer for the American Cancer Society, said the FDA was correct in asking for further evidence.
Thomas Robbins, 74, of Forest City, N.C., was diagnosed in 2002 with prostate cancer that was growing despite hormone treatment.
"They wanted to give me chemo," said Robbins. Instead, he decided to enroll in the Provenge study instead.
"Did it help me? I can't 100 percent guarantee, but I think it did," he told the Associated Press.
Advocacy groups were also excited over the results of the study.
"For the first time, we have real clinical validation that cancer can be fought by stimulating the body's immune system," said Scott Riccio, founder of Accelerate Progress. "Hundreds of thousands of men fighting prostate cancer will now have real hope that a safe and effective new option will be available to them in their fight for life."
Prostate cancer, the most common non-skin cancer in American men, caused 28,660 deaths last year.
On the Net:
- Dendreon Corp
- Eastern Virginia Medical School
- American Urological Association
- University of California in San Francisco
- American Cancer Society