Finally, on Monday, Dendreon announced that it completed its Food and Drug Administration (FDA) application for the approval of Provenge (sipuleucel-T).
Provenge is designed as a vaccine that stimulates the body’s own immune system to fight prostate cancer. It is a different type of vaccine from what most of us knows as it is given as an actual treatment rather than as a preventive measure.
Although I opened this post saying “finally,” I was only expressing my frustration. I have grown very impatient waiting for the next round with the FDA, now we are finally moving a head. In reality, the completion of the application for approval is ahead of the company’s prior stated timeline for 2010, but it has not been soon enough for my liking.
Since the initial application for the approval of Provenge, Dendreon has developed positive data supporting the ability of the vaccine to extend survival for men with metastatic prostate cancer, the FDA’s gold standard. This most recent trial enrolled 512 men who were randomized 2:1 to receive provenge or placebo.
The trial participants were followed with bone scans to monitor disease progression. On progression, patient were treated at the discretion of their physicians, but the patients who had been randomized to receive placebo were eligible to receive a frozen version of sipuleucel-T based on their cells at the time of original extraction.
The results of this trial are as follows:
• The average age of patients receiving provenge was 72 years compared to 70 years for patients receiving placebo
• The average PSA level of patients receiving provenge was 51.7 ng/ml as compared to 47.2 ng/ml for patients receiving placebo.
• Median overall survival for patients receiving provenge was 25.8 months.
• Median overall survival for patients receiving placebo was 21.7 months.
• There was a 4.1 month increase in overall survival for patients treated with provenge.
• 31.7 percent of provenge patients were alive at 3 years as compared to 23.0 percent of placebo patients.
There is no question that provenge provided a statistically and clinically significant survival benefit compared to placebo. Even though we are still talking about a life extension in terms of months, this survival benefit is twice as long as that offered by docetaxel in the studies that led to approval of that drug for a similar population of patients.
As opposed to docetaxel, the most common side effects of provenge reported in this trial were flue like symptoms similar to those shown in prior studies of this treatment: chills in 54.1 percent of patients, pyrexia (fever) in 29.3 percent, and headache in 16 percent. Most of these side effects occurred within 2 days of each of the three rounds of drug infusion.
It is my personal opinion that Provenge has met all the criteria for approval set by the FDA in 2007. We need to monitor the FDA process and make sure that many of us turn out to support the vaccine’s approval when the approval hearing is held.
Joel T Nowak MA, MSW