Blood Thinner Extended Use Study Finds Little Difference in Warfarin, Xarelto, Eliquis Bleeding Rates

While newer blood thinning medications do provide lower rates of potentially dangerous blood clots, the findings of a new study suggests the drugs are no better at preventing major bleeding events than older drugs like warfarin.

Harvard researchers say blood thinners like Eliquis (apixaban) and Xarelto (rivaroxaban) are modestly better at preventing venous thromboembolism events (VTE) than the older blood thinner warfarin. However, claims the drugs are less likely to cause major bleeding appear to be unsubstantiated, with all three drugs carrying about the same risks. The findings were published on March 15 in the Journal of the American Medical Association (JAMA).

Xarelto and Eliquis are both part of a relatively new class of drugs that have been marketed as a replacement for warfarin, which has been the go-to blood thinner for decades. However, both drugs were linked to risks of severe and uncontrollable bleeding events before reversal agents were introduced in 2018.

In this latest study, researchers wanted to look at the performance, safety and efficacy of the three drugs for 90 days, which is the recommended length of therapy for managing venous thromboembolism. They conducted an exploratory retrospective cohort study using data from fee-for-service Medicare gathered from 2009 to 2017, as well as from commercial insurance databases.

The study included 64,642 adults who continued VTE treatment for more than 90 days. The researchers looked for recurrent VTEs and hospitalization for major bleeding.

According to the findings, Eliquis performed better than warfarin at preventing VTE, with 9.8 VTE hospitalizations per 1,000 person-years, compared to warfarin’s 13.5 per 1,000 person-years. However, almost every other metric the researchers looked at was a wash, both for major bleeding risks and VTE prevention.

“In this exploratory analysis of patients prescribed extended-duration oral anticoagulation therapy after hospitalization for VTE, prescription dispenses for apixaban beyond 90 days, compared with warfarin beyond 90 days, were significantly associated with a modestly lower rate of hospitalization for recurrent VTE, but no significant difference in rate of hospitalization for major bleeding,” the researchers concluded. “There were no significant differences for comparisons of apixaban vs rivaroxaban or rivaroxaban vs warfarin.”

Incidents of unstoppable bleeding have resulted in thousands of reports involving injury or death for patients using the new drugs. About 30,000 Xarelto lawsuits were filed against the drug makers, alleging that users and the medical community were not adequately warned about the risk of problems linked to the drug.

Following a handful of early bellwether trials, which were held before U.S. District Judge Eldon Fallon in the Eastern District of Louisiana to help gauge how juries may respond to certain evidence and testimony that was likely to be repeated throughout the litigation, a global Xarelto settlement was reached in March 2019, resolving nearly all claims.