Xarelto, Pradaxa No Safer Than Warfarin: Study

New blood thinners released in recent years, such as Xarelto and Pradaxa, have been promoted as superior to warfarin, which has been the leading anticoagulation treatment. However, the findings of a new study suggest that these new generation medications may be no safer than the older drug. 

In a study published in this month’s edition of the Canadian Journal of Cardiology, researchers from the Southlake Regional Health Centre in Ontario, Canada, found that the safety profiles of the drugs were nearly identical when it came to bleeding risks and other side effects common to blood thinners used to treat patients with atrial fibrillation.

Researchers looked at data on 901 patients who underwent cardioversion and were given either warfarin, also sold under the brand name Coumadin, and the newer drugs Pradaxa and Xarelto. Researchers looked at the number of strokes, transient ischemic attacks, and bleeding events suffered by patients taking the drugs.

“Bleeding rates were low, with no significant difference between the groups,” the researchers reported. The researchers say that all three drugs appear to be reasonable options for patients with atrial fibrillation.

The manufacturers of the new “Factor Xa” anticoagulants have aggressively promoted the drugs as safer than warfarin, claiming that patients need less blood monitoring to ensure that levels of the drugs did not get to high and increase the risk of bleeding events. However, a number of recent studies and internal documents have raised questions about those claims, suggesting that blood monitoring on Xarelto and Pradaxa may actually have prevented many life-threatening bleeding problems.

The findings appear to eliminate a primary selling point of the new drugs.

Xarelto and Pradaxa Bleeding Risks

Pradaxa (dabigatran) was introduced by Boehringer Ingelheim in October 2010, as the first member of this new generation of anticoagulants. Xarelto (rivaroxoaban) was introduced by Bayer and Johnson & Johnson’s Janssen Pharmaceuticals in 2011, as the second member of this class, and it has since grown to become the best seller of the two.

Coumadin (warfarin) has been the go-to blood thinner for prevention of strokes among patients with atrial fibrillation for decades, and is widely available as a generic and substantially less expensive than the new medications. To gain a market advantage and encourage doctors to switch patients to these new medications, the manufacturers have suggested that the new drugs are safer than warfarin and easier to use.

As the popularity of the new generation of drugs has increased, concerns have emerged about the bleeding risk of Xarelto and Pradaxa, as large numbers of adverse event reports have been linked to uncontrollable bleeds among users of the medications.

While all blood thinners carry a risk of bleeding problems, Xarelto and other members of this new generation of anticoagulants lack an approved antidote that doctors can use to reverse the effects of the drug. While doctors can quickly stop the blood thinning effects of warfarin, there is no Xarelto antidote, leaving physicians unable to stop bleeding problems that may occur during use, which may increase the risk of more severe injury or death.

Questions about the importance of blood monitoring on the newer drugs and the potential lack of safety benefits over warfarin have led to concerns over the marketing practices by the drug manufacturers.

Boehringer Ingelheim has previously faced over 4,000 Pradaxa lawsuits alleging that the drug maker provided inadequate warnings for consumers and the medical community. Following several years of litigation, a Pradaxa settlement agreement was announced earlier this year, with Boehringer Ingelheim agreeing to pay $650 million to resolve the claims for an average of about $150,000 each.

Bayer and Janssen now face a growing number of Xarelto lawsuits, which raise similar allegations that the drug makers placed their desire for profits before the safety of consumers by aggressively marekting the drug without adequate warnings, and for failing to fully explore all potential reversal agents that may have made the medication safer.

Many plaintiffs also allege that the benefits provided by the medication do not justify the risks, indicating that the drug makers should issue a Xarelto recall until a reversal agent can be developed.

Last week, the U.S. Judicial Panel on Multidistrict Litigation heard oral arguments about whether to centralize the Xarelto cases in the federal court system before one judge for coordinated pretrial proceedings.