The co-authors of Invasion of the Prostate Snatchers, blog alternate posts weekly. We invite you to post your comments.

Tuesday, October 4, 2011

FDA Roulette


The notoriously stingy and demanding FDA gave the go ahead for two new treatments for prostate cancer in 2010.  New approvals are rare because of the hundreds of millions of dollars required to undertake the type of studies that the FDA requires. The FDA wants studies that randomly allocate men into two comparison groups. One group gets the new medicine. The other group gets an ineffective fake called a placebo. FDA approval comes when men getting the new medicine live longer than those given the placebo.

Finding volunteers willing to participate in these types of studies is difficult. The men know there is a 50% chance they will get an ineffective placebo. Who wants to take the chance of getting a sugar pill as their treatment? Even so, some men are so desperate, they sign up, hoping to be among the lucky ones who receive the real McCoy.

These studies often run for years because the study ends when the study participants die from progressive cancer.  To find men willing to participate, the supervising companies that organize and run these studies need contractual relationships with a hundred or more study centers. Just keeping track of all these different patients, at so many different locations, over a period of several years, is in itself very costly.

Provenge is the first FDA approved treatment for prostate cancer that works by strengthening the immune system. Dendreon is the name of the company that has patented a process of harvesting immune cells out of the blood by means of a technique known as “plasmapharesis.” Plasmapharesis is a three hour process similar to dialysis that extracts immune cells from the blood. The harvested cells are then taken to a special laboratory and mixed with substances that enhance their aggressiveness against cancer.  The cells are then re-infused back into the same patient. 

Provenge’s primary appeal is the low incidence of side effects. The treatment, which does not rely on chemotherapy, is so revolutionary that at first the FDA was very skeptical. They dragged their feet for years, forcing the company to run their studies over and over.  Lo and behold, additional studies again demonstrated that Provenge-treated men were 30% more likely to be three years after their treatment with Provenge compared to the men who received a placebo. Dendreon should be commended for patiently persevering time after time when the FDA kept turning them down. Now men with prostate cancer have access to an effective treatment that has very few side effects.

The other new treatment recently approved by the FDA, Jevtana, falls into the more familiar category of chemotherapy.  Jevtana was approved in July 2010 based on a randomized survival study evaluating Jevtana compared to an older, ineffective type of chemotherapy called Mitoxantrone. 755 men were treated with either Jevtana or Mitoxantrone. The survival of men receiving Jevtana was 30% better then the men treated with Mitoxantrone.  

This remarkable achievement took some industry experts by surprise because the participants in the trial had all been treated previously and become resistant to another type of chemotherapy called Taxotere.  Historically, resistance to Taxotere has been a bad sign predicting resistance to all types of chemotherapy. Jevtana, unlike Provenge has the traditional side effects of chemotherapy such as tiredness, hair loss and increased risk for infection. Even so, reversing cancer in men with Taxotere-resistant disease is quite an accomplishment. 

The FDA finally agrees that both Jevtana and Provenge are proven to make men live longer. Studies are ongoing with these newly-approved medicines to see if combining them with other drugs can further enhance their effectiveness. In the meantime, men with prostate cancer need to be aware that these new and effective tools are available.        

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