Data on trial of anticoagulant is to be reanalyzed after discovery that investigators used faulty device

Data from the key phase III trial that allowed the oral anticoagulant rivaroxaban on to the market for the prevention of ischemic stroke in non-valvular atrial fibrillation is being reanalyzed because of the use of a faulty device.

The European Medicines Agency has also told The BMJ that it has launched an investigation into the trial.

The ROCKET-AF trial, published in the New England Journal of Medicine in 2011, compared rivaroxaban, which is manufactured by Bayer and marketed in the United States by Janssen, part of Johnson and Johnson, as Xarelto, with warfarin in more than 14 000 people.1

The trial used the INRatio device, made by Alere, to determine whether, and by how much, patients’ doses of warfarin should be adjusted to keep the drug in the right therapeutic range. Too much warfarin and patients are at an increased risk of bleeding; too little and they are at risk of clots.

However, The BMJ has …