FDA Gives GSK a Lesson in Prostate Geometry

(MoneyWatch)  The FDA gave GlaxoSmithKline a lesson in geometry last week when it sent the company a warning letter over its "misleading" claims for Avodart, a prostate reduction drug.

FDA's main objection was the scale of the animation in the Avodart ad that was supposed to represent a man's shrinking prostate.

GSK used some model planets from the solar system to illustrate the prostate, contrasting a larger planet with a smaller planet. Subtle! The FDA said GSK made a high-school level mistake when it comes to the relationship between size and volume:

The magnitude of the change depicted in the visuals showing a large planet and a small planet (representing the actor's prostate) overstates the efficacy of Avodart.

The visual of the planet shrinking in size represents a reduction in prostate volume that is much greater than the reduction actually achieved with Avodart therapy in clinical trials. In fact, the approximately 20 ?€" 25% reduction in volume [under Avodart treatment] corresponds to a difference in diameter of less than 10%.

As you can see from the screenshot, that planet is about half the diameter of its original size -- a volume reduction much larger than 25 percent.

Seems a little harsh? I thought so too. However, the FDA has GSK cold on its other claim. From the ad:

"Other medicines, they don't treat the cause, because they don't shrink the prostate."

The FDA:

The TV ad clearly suggests that Avodart is the only medication that shrinks the prostate, when this is not the case.

GSK must withdraw and correct the spot.