and its impact on the clinical trial that eventually led to the approval of a major indication for Xarelto, the US Food and Drug Administration (FDA) has weighed in, defending its support for Xarelto and the study results that led to the agency’s conclusion.
The INRatio anti-coagulation monitoring device, manufactured by Alere Inc., was the primary monitoring device used in the clinical trial that compared the effectiveness of anticoagulant Xarelto against the de facto standard of the day, warfarin – branded as Coumadin – for patients with atrial fibrillation. Xarelto was initially approved in July, 2011 for reducing the risk of blood clots, deep vein thrombosis and pulmonary embolism after knee or hip replacement surgery.
However, Bayer AG and Johnson & Johnson (J&J) sought an expanded indication for Xarelto to include patients with atrial fibrillation, otherwise known as an irregular heartbeat. According to the American Heart Association, atrial fibrillation doubles the risk for heart-related death and increases the risk for stroke five-fold.
A total of 14,000 study participants provided the primary data used to determine the safety and efficacy of rivaroxaban (Xarelto) for atrial fibrillation – and its effectiveness when compared with warfarin (Coumadin) – gathered from the clinical trial known as ROCKET AF.
The warfarin group was monitored using INRatio, a measuring device that was subject to an Alere recall due to inaccurate readings encountered by some of the warfarin patients. Those readings are key, given that results from International Normalized Ratio (INR) tests determines in the given patient how quickly a patient’s blood clots. Warfarin dosages are adjusted accordingly. Those readings and the accuracy thereof, were important to the approval of Xarelto for atrial fibrillation with regard to rivaroxaban’s safety and efficacy when compared with warfarin.
In September, a report that appeared in BMJ suggested that Janssen Pharmaceuticals – the unit of J&J responsible for Xarelto – was aware about the problems with the Alere INRatio device, but failed to inform regulators.
As Heidi Turner reported previously, the ROCKET AF trial concluded there were no significant difference between rivaroxaban and warfarin in terms of risk for a major bleeding event in general, but nonetheless found that warfarin was associated with an increased risk for fatal bleeds in the brain. That being said, inaccurate readings through the INRatio device may have skewed the results in rivaroxaban’s favor.
It was further alleged that Janssen re-checked the results provided from Alere through the Covance recheck system, but is alleged not to have shared the results with the monitoring board associated with the ROCKET AF trial. It has also been alleged that Bayer was not apprised of the Covance recheck, given that Janssen was the primary overseer for the clinical trial.
It has also been reported that while an independent reanalysis of the ROCKET AF results found no impact to clinical trial outcomes stemming from the allegedly faulty INRatio device, the BMJ report suggests that it is not beyond the realm of possibility that the reanalysis itself may have been inaccurate to some degree.
Now the FDA has weighed in on the Alere recall and the potential for inaccurate blood monitoring. In its response released in October (10/11/16), the federal drug and medical device agency indicated its determination that the Alere INRatio device did not, in all likelihood, have any substantial impact on the ROCKET AF trial results.
To that end, the FDA has determined that Xarelto remains safe and effective for the treatment of atrial fibrillation.
READ MORE ALERE INRATIO RECALL LEGAL NEWS
Xarelto was released to the market as a safe and effective alternative to Coumadin (warfarin), with the added benefit of reduced need for stringent monitoring, which remains the bastion for warfarin in order to keep the anticoagulant within safe levels. Patients and the medical community in general embraced Xarelto, potentially without knowledge of the lack of a reversing agent to stem bleeding.
Coumadin can be reversed with an infusion of Vitamin K. However, Xarelto does not respond to Vitamin K in the same fashion.
An increase in the number of plaintiffs bringing an INRatio lawsuit in association with Xarelto litigation remains a very real possibility.