Regulators probe trial of Bayer's Xarelto on use of faulty device

The European Medicines Agency is no longer sure whether results from a trial of Bayer's next-gen clot-fighter Xarelto are accurate--and a blood-clotting testing device is to blame.

A defect in the device may have impacted the clotting results in some patients in one arm of the study, which pitted the new-age anticoagulant against old-guard therapy warfarin, the agency said in a statement seen by Reuters. The EMA is now investigating, and it'll publish results from the probe when it wraps up.

Across the pond, the FDA said it was "aware of concerns regarding the INR device and its use in the Rocket AF trial and is reviewing relevant data."

"Bayer is working closely with health authorities to address any questions they may have," a company spokeswoman told Reuters. "Study after study continues to confirm that Xarelto is performing as expected with a positive benefit-risk profile."

Duke University's Clinical Research Institute, which used the faulty device while conducting some of the trial work, said it didn't have an impact on the study's overall results.

News of the investigation sent Bayer's shares downward, though any impact on Xarelto--tabbed as one of the company's 5 new growth products with $1.83 billion in sales last year--would probably be small, analysts at Kepler Cheuvreux and Equinet told Reuters.

"Given that ... probably hundreds of different devices were used to assess the control group patients, a single defective device is unlikely to have a statistically relevant effect on the overall outcome," Kepler Cheuvreux's Fabian Wenner told the news service.

While Xarelto--which Bayer shares with Johnson & Johnson ($JNJ)--leads a field of newcomer blood thinners including Boehringer Ingelheim's Pradaxa and Bristol-Myers Squibb ($BMY) and Pfizer's ($PFE) Eliquis--it's still competing against warfarin, too.

There's "still quite a ways to go" when it comes to unseating the older, less convenient therapy, Jörg Kreuzer, Boehringer's cardiovascular medicine head, told FiercePharma in a September interview. More and more people are starting on the new class of drugs for stroke prevention, "but still more than half of the patients are on warfarin," he said.

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