Xarelto Reversal Agent Delayed Again, More Clinical Trials May Be Needed

Important Andexxa Update – December 22, 2025: An Andexxa recall was announced on December 18, 2025, and the drug was subsequently removed from the U.S. market after regulators concluded it failed to effectively reverse life-threatening bleeding while increasing the risk of heart attack, stroke, dangerous blood clots and related deaths. Following the recall, Andexxa lawsuits are now being investigated to determine whether the drug should never have been introduced or kept on the market.

A potential reversal agent designed to control deadly bleeding events linked to the side effects of Xarelto and other new-generation blood thinners continues to face regulatory hurdles, after years of delays. 

AndexXa is designed to be an antidote for a class of drugs known as Factor Xa Inhibitors, which include novel oral anticoagulants introduced as a replacement for warfarin as a preventative treatment for strokes and other problems linked to atrial fibrillation. However, Xarelto and other members of this class have been linked to thousands of reports involving severe and fatal injuries, when users experienced bleeding that doctors were unable to stop or reverse.

Unlike warfarin, which can be quickly reversed with a known antidote, no approved reversal agent for Xarelto has been available since the drug was introduced in 2011.

Portola Pharmaceuticals has been working to convince the FDA to approve AndexXa for nearly two years, without success.

After the Xarelto reversal agent was rejected by the FDA in 2016, Portola told investors that it hoped to get the drug approved by May 4 of this year. However, a report by BioPharmaDive indicates that Portola CEO William Lis recently indicated that the FDA is unlikely to approve the drug unless Portola conducts a full randomized clinical trial, which would take significantly more time.

FDA officials have been cautious about the reversal agent, which may be used by millions of patients, and have called for more evidence that it is safe and effective. In addition, a 2016 study showing positive results for AndexXa (andexanet alfa) has come under scrutiny by doctors, who say that the study’s researchers may have been overstating its benefits.

Xarelto Litigation

Incidents of unstoppable bleeding have resulted in injury and death for patients using the new drugs. Currently, there are more than 18,000 Xarelto bleeding lawsuits pending as part of a federal multidistrict litigation (MDL), which is centralized before U.S. District Judge Eldon Fallon in the Eastern District of Louisiana. Each of the claims raise similar allegations that users and the medical community were not adequately warned about the risk of uncontrollable bleeding on Xarelto.

Following a handful of early bellwether trials, which were held before Judge Fallon to help gauge how juries may respond to certain evidence and testimony that is likely to be repeated throughout the litigation, no progress has been made in negotiating Xarelto settlements or another resolution for the claims.

As a result, Judge Fallon recently ordered the parties to select 1,200 Xarelto cases for discovery, which may then be remanded back to U.S. District Courts nationwide for individual trial dates.