Boston Scientific Stent Study Flawed
August 14th, 2008 laurie
Boston Scientific is awaiting approval for a new heart stent, the Taxus Liberte, which the company claims did well in a clinical trial. After viewing the data, the Wall Street Journal reports that this success is based on flawed research.
The WSJ reports that Boston Scientific Boston Scientific’s claim was based on a flawed statistical equation that favored the Liberte stent. Using a number of other methods of calculation — including 14 available in off-the-shelf software programs — the Liberte study would have been a failure by the common standards of statistical significance in research. Boston Scientific isn’t the only company to use the equation, known as a Wald interval, which has long been criticized by statisticians for exaggerating the certainty of research results. Rivals Medtronic Inc. and Abbott Laboratories have used the same equation in stent studies, the Journal reports. But in those cases, any boost provided by the Wald equation wouldn’t have changed the outcome of the study. In the Liberte study, the equation’s shortcomings meant the difference between success and failure in the study’s main goal.
According to the Journal, Boston Scientific says the study, known as Atlas, was a success because the company’s methodology, including the Wald equation, was accepted by the FDA before the study began, and it was bound to follow that method.
The FDA hasn’t approved the Liberte for sale in the U.S. But the agency has given Boston Scientific an “approvable” letter that indicates it will OK the stent when it lifts a new-product moratorium it imposed on the company two years ago for reasons unrelated to the Liberte application. The company has said it expects the moratorium to be lifted this year.
