Can Xarelto Trial Data Be Trusted? It Depends Who You Ask

Boston, MAAs more Xarelto lawsuits are added to the multidistrict litigation, concerns have been raised that a medical device used in Xarelto’s clinical trial was faulty, which may have affected test results. Now critics are asking for an investigation, while Janssen Pharmaceuticals and the study’s authors maintain the study’s conclusions are accurate.

The study in question is the ROCKET-AF trial (Rivaroxaban Once Daily Oral Direct Factor XA Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation), which was published in 2011 in the New England Journal of Medicine. That study found that both rivaroxaban (the generic version of Xarelto) and warfarin - the older-generation anticoagulant - each reduced the risk of ischemic stroke or systemic embolism. The study also found no significant difference between rivaroxaban and warfarin in the risk of a major bleeding event, but found rivaroxaban was associated with a lower risk of bleeding in the brain and fatal bleeding.

According to editors at The BMJ (2/3/16), Janssen and Bayer Pharmaceuticals relied only on ROCKET-AF when it applied for approval from the FDA and European regulators. The study used a device called an INRatio Monitor System, which measures how long it takes for blood to clot and which was recalled in December 2014 due to “clinically significantly lower” test results than patients might see in laboratory testing.

“A falsely low reading could mean that patients had their warfarin dose unnecessarily increased, leading to a great risk of bleeding,” Deborah Cohen writes in The BMJ. “In terms of the trial results, it could make rivaroxaban seem safer than it was in terms of the risk of bleeding and throws doubt on outcomes used to support the use of the world’s best selling new oral anticoagulant.”

Some critics have now called for an independent investigation of the ROCKET-AF trial, to determine whether the results were skewed by the recalled device. The FDA reportedly told The BMJ that it would review relevant data. Representatives for the device maker, meanwhile, said their own analysis confirmed the results of the study.

In a letter to The New England Journal of Medicine (2/3/16), the study’s authors reviewed data and found that the possible malfunction of the device “did not have any significant clinical effect on the primary efficacy and safety outcomes in the trial.” The European Medicines Agency has also said in a news release posted on its website that the recalled device did not affect the results of the ROCKET-AF trial.

As of January 15, 2016, there were 2,826 lawsuits consolidated for pretrial proceedings in MDL-2592, In Re: Xarelto (Rivaroxaban) Products Liability Litigation before US District Judge Eldon E. Fallon.