Xarelto Adverse Events Now Outnumber Pradaxa’s: Report

The blood thinner Xarelto has surpassed its rival, Pradaxa, in both prescriptions and the number of severe adverse events reported by its users, according to the findings of a new analysis.  

In the latest issue of the Institute of Safe Medication Practices (ISMP) QuarterWatch Report(PDF), which reviews and analyzes adverse event data submitted to the FDA, the number of complaints submitted involving Xarelto surpassed Pradaxa, which at one point generated more adverse event reports involving severe or fatal health problems than any other drug monitored by the group.

The report indicates that increasing sales of Xarelto and falling sales of Pradaxa are likely behind the shift, as doctors switch from Pradaxa to a drug they are discovering may be just as dangerous.

According to the ISMP, there were 680 serious adverse event reports linked to Xarelto, compared to only 528 for Pradaxa over the last year. The reports involving Xarelto problems are climbing, while reported Pradaxa side effects are declining, researchers found.

Pradaxa and Xarelto are both  part of a new family of anticoagulants known as direct factor Xa inhibitors. The blood thinners have been promoted as superior alternatives to warfarin, which is commonly known by the brand name Coumadin, for prevention of strokes among patients with atrial fibrillation.

While warfarin has been the go-to anticoagulant for decades, it is also known to be a risky drug that can cause bleeding problems, requiring careful monitoring during treatment to maintain the appropriate dose. Xarelto and Pradaxa are promoted as easier to use, but lack an approved reversal agent that can be used to stop bleeding problems that may develop.

When a user of warfarin experiences a hemorrhage or severe bleed, doctors are able to counteract the blood thinning effects of the medication with a dose of vitamin K. However, there are not currently any FDA-approved reversal agents for Xarelto or Pradaxa, leaving doctors unable to control bleeding in many cases. This has resulted in a spike of adverse events involving severe hemorrhages and deaths associated with the medications.

With Johnson & Johnson and Bayer’s Xarelto, however, some doctors have recently found off-label treatments to stop the bleeding, though there is no official reversal agent. Boehringer Ingelheim, the maker of Pradaxa, says it is on the verge of developing a reversal agent that would make that drug much safer as well. However, there are other safety measures that could make Pradaxa even safer, according to the ISMP.

“Newly published data also show that the bleeding risks of [Pradaxa] could be substantially reduced if

two therapeutic options available in most advanced countries were approved in the United States,” the ISMP report states. “Those options are a lower, 110 mg twice daily (BID) dose, and a laboratory test capable of identifying patients who need a dose adjustment because the effect on thrombin inhibition is either excessive, increasing the risk of severe bleeding, or sub-therapeutic, exposing the patient to a higher risk of stroke or other blood-clot related adverse event.”

ISMP has urged the FDA to recommend these options to doctors prescribing Pradaxa, according to the report.

Xarelto and Pradaxa Lawsuits

Boehringer Ingelheim currently faces more than 2,000 Pradaxa lawsuits filed by individuals who allege that the drug maker failed to warn the medical community that there was no reversal agent.

Since August 2012, the federal Pradaxa litigation has been consolidated as part of a Multidistrict Litigation (MDL), which is centralized before U.S. District Judge David R. Herndon in the Southern District of Illinois to reduce duplicative discovery, avoid conflicting rulings from different judges and to serve the convenience of the parties, witnesses and the courts. The company also faces Pradaxa lawsuits in state courts in Illinois, California and Connecticut.

As part of the coordinated management of the cases in the federal court system, Judge Herndon has scheduled a series of early trial dates in the Pradaxa MDL, known as bellwether cases. These trials are set to begin between August 2014 and February 2015, with the outcomes designed to help the parties gauge how juries are likely respond to certain evidence and testimony that may be repeated throughout a large number of cases.

In February, what is believed to be the first Xarelto lawsuit was filed against Johnson & Johnson and Bayer in the Philadelphia County Court of Common Pleas, raising similar allegations.