Three pharmaceutical companies working together on a possible antidote for Eliquis bleeding have announced the results of a study on the efficacy and safety of that antidote.

Portola Pharmaceuticals, Bristol-Myers Squibb Company, and Pfizer, Inc. are cooperating to develop a medication to counter the anticoagulant side effects of Eliquis. Such an antidote would be useful in cases of excessive bleeding or where emergency surgery is needed.

Background on Eliquis

Eliquis, also known as apixaban, is one of a new generation of anticoagulant medications. It’s indicated to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. Atrial fibrillation creates a risk that blood clots may form and travel to the brain, causing a stroke; anticoagulant medications help reduce that risk.

Eliquis is also indicated to prevent deep vein thrombosis following hip or knee surgery, to treat deep vein thrombosis or pulmonary embolism, and to reduce the risk of recurrent deep vein thrombosis and pulmonary embolism after initial therapy.

Since 1954, only Warfarin (sold under the brand names Coumadin and Jantoven) had been FDA-approved to prevent stroke in atrial fibrillation patients. Only recently have new anticoagulants been approved and introduced to the market, including: Pradaxa (dabigatran), Xarelto (rivaroxaban), and Eliquis. The FDA says the clinical trials for these drugs showed they were all at least as effective as Warfarin, if not more so, at preventing stroke.

Like all medications that inhibit blood clotting, Eliquis increases the possibility of excessive bleeding. Warfarin maintains one significant advantage over the three new anticoagulants, in that its anticoagulant effect can be inhibited by administering Vitamin K.

The problem with Eliquis bleeding, as with the other two new anticoagulants, is that there is no antidote on the market that can counteract the bleeding effect. When Eliquis causes excessive bleeding, the patient must simply wait for the body to finish metabolizing and eliminating the drug.

Moreover, spontaneous bleeding is not the only possible complication. Patients who happen to need unexpected surgery while taking Eliquis must stop taking it and delay surgery until Eliquis has cleared their system, or else they risk losing an excess of blood during the surgery.

New Antidotes in the Works

An antidote for Eliquis bleeding is what Portola, Bristol-Myers Squibb, and Pfizer are now working on. The new study evaluates the efficacy and safety of the drug, andexanet alfa, as a possible Eliquis antidote.

The study examined the effects of andexanet alfa in over 30 healthy volunteers ages 50 to 75. Researchers found that andexanet alfa quickly reversed the bleeding effect of Eliquis. They say patients tolerated andexanet alfa well and that “no serious adverse events, thrombotic events, or antibodies to Factor X or Xa.” The researchers also report that no patients had to discontinue andexanet alfa due to any adverse events, though six subjects did report mild infusion reactions.

The researchers concluded that andexanet alfa was effective for both short and sustained suppression of Eliquis’s anticoagulant effect. They also found that discontinuing andexanet alfa allowed the anticoagulant effect to resume successfully.