December 1, 2015 — A defective INR-testing device used to calibrate warfarin dosage may have skewed results of the ROCKET-AF clinical trial in favor of Xarelto, according to MedPage Today.
One year ago, the FDA issued a Class 1 recall for the Alere INRatio and INRatio2 PT/INR Monitor System, warning that it could produce erroneously low INR results (blood-clotting rates).
The ROCKET-AF study concluded that Xarelto and warfarin had comparable rates of bleeding. However, faulty INRatio devices may have resulted in warfarin patients being given too much of the blood-thinning drug.
Depending on how many patients received false readings, the results could have masked increased risks of bleeding and death for Xarelto patients, according to the Project on Government Oversight.
Researchers at Duke University and the European Medicines Agency are currently re-assessing the study. However, some safety advocates are questioning why the devices were used in the first place. The FDA knew about the problem and issued warning letters in 2005 and 2006.
The ROCKET-AF study opened enrollment in 2006 and was published in the New England Journal of Medicine in 2011. Xarelto was approved by the FDA less than two months later, against the objections of some reviewers who were concerned that warfarin was not administered in an optimal way.
Responsibility for the problem may fall on Dr. Robert Califf, co-chairman of the ROCKET-AF study and President Obama’s nominee for the next FDA Commissioner. He runs a $200 million clinical research facility at Duke University that receives most of its funding from pharmaceutical companies, according to the New York Times.