The popular blood-thinner Pradaxa (dabigatran) has come under fire from victims of serious side effects, consumer rights organizations and medical researchers who question its safety in attempting to prevent heart attacks.
At the same time, its manufacturer is currently attempting to defend itself against a growing number of Pradaxa lawsuits claiming that the medication is unsafe because it can cause life-threatening internal bleeding.
Among the allegations levied against Pradaxa is that unlike one of its major competitors, warfarin, there is no cure for the internal bleeding problems that it is alleged to have caused. Read mroe on the Pradaxa internal bleeding
The Food and Drug Administration has become concerned enough about the reports of serious bleeding (rates of as high as 10 percent of patients using Pradaxa) that it has issued a health alert, ordered a change on warning labels of the medication and is conducting a review of links between Pradaxa use and the problem.
In the meantime, Forbes Magazine’s health page is reporting that Boehringer Ingelheim has halted its attempt to expand Pradaxa’s use to patients with mechanical valves in its battle with the traditionally dominant anticoagulant warfarin in the pharmacy marketplace.
The stakes are high. Blood-thinners are among the largest selling and most profitable medications, generating billions of dollars in global sales. Here’s what Forbes had to say about recent important tests involving Pradaxa:
Despite the recent advent of novel oral anticoagulants, the much-maligned warfarin remains the only current option available for patients who have received a mechanical valve. Now the first trial to explore this indication for a newer oral anticoagulant has suffered a setback.
Last year Boehringer Ingelheim announced the launch of the RE-ALIGN trial, a phase 2, open-label, 12-week randomized comparison of warfarin and dabigatran (Pradaxa) in 400 patients who received a mechanical valve. There were two arms in the trial. The first arm randomized patients during their initial hospital stay. The second arm randomized patients more than 3 months after their surgery.
Now, following the advice of the trial’s Data Safety Monitoring Board, Boehringer Ingelheim said it had discontinued the first arm of the trial, the post-surgery arm, due to “lower than projected plasma levels of dabigatran in this population, and an imbalance in reports of thromboembolic events (primarily strokes).” The trial’s second arm with patients who received a valve more than 3 months before enrollment in the trial is unaffected by this decision and will continue as planned.
Boehringer-Ingelheim said that the news about RE-ALIGN does “not affect the positive benefit/risk profile of Pradaxa 150 mg for the current labeled indication” of stroke prevention in patients with non-valvular atrial fibrillation. “RE-ALIGN is evaluating a different patient population and different doses than were studied in the RE-LY trial.”
Dabigatran has been approved in Europe, but not in the United States, for venous thromboemoblism (VTE) prevention after knee and hip replacement surgery. Rivaroxaban (Xarelto) has been approved for both VTE prevention and treatment in the United States and Europe. To date there have been no head-to-head comparisons of the newer anticoagulants.
According to a recent study in Circulation: Cardiovascular Quality and Outcomes, dabigatran now has about 19% of the oral anticoagulant market, mostly for the approved treatment of AF “but increasingly for off-label indications” as well.
A recent letter in the Journal of the American College of Cardiology provided information about the off-label use of dabigatran in two mechanical valve patients. Both patients developed thrombosis after switching to dabigatran from warfarin. The authors noted that “while there is a wealth of data and clinical experience on dosing and therapeutic response to warfarin in this context, these data are unavailable for dabigatran.”
Although newer anticoagulants “hold tremendous promise for mechanical valve anticoagulation… there is a need for dose-finding studies and clinical trials to demonstrate safety and efficacy in this setting.”