The INRatio device was used during a study (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) of the anticoagulant rivaroxiban (known by the brand name Xarelto). Results from the ROCKET AF trial were used to justify the device's approval on the market. INRatio is used to determine how quickly a patient's blood is clotting—vital information for patients on anticoagulant medications. The device compares how quickly the patient's blood clots to the International Normalized Ratio (INR) test. Based on the results from the INRatio, a patient's dosage of anticoagulant could be increased or decreased.
Rivaroxiban is an anticoagulant medication, and to test its safety and efficacy before being approved for the market the drug was subject to the ROCKET AF trial during which its results were compared with warfarin, an older anticoagulant medication. The results of that trial were published in the New England Journal of Medicine in 2011. The trial involved the use of the INRatio device to determine how quickly patients' blood clotted when they took warfarin. In 2014, however, the Alere INRatio Monitor System was recalled due to some patients experiencing abnormal readings. Those abnormal readings could result in patients having their dosage of an anticoagulant increased, also increasing the risk of experiencing a bleeding event.
The ROCKET AF trial concluded that rivaroxaban and warfarin had no significant difference in regards to the risk of a major bleeding event, but did find that warfarin was associated with an increased risk of fatal bleeding in the brain. But if patients were exposed to unnecessarily higher doses of warfarin due to faulty data from the INRatio device, the results of the study could be somewhat skewed making rivaroxaban seem more favorable.
READ MORE ALERE INRATIO RECALL LEGAL NEWS
An independent reanalysis of the ROCKET AF results was conducted and concluded that trial outcomes were not affected by the faulty device, but according to The BMJ that reanalysis may itself have been faulty.
"Perhaps most alarming, Janssen did not tell the FDA about the recheck programme or trial investigators' concerns about the device during the approval process in 2011," Deborah Cohen writes for The BMJ.
The FDA is reportedly now investigating the trial.