7 Things Pharmacists Should Know About Praxbind

The FDA has granted accelerated approval for Boehringer Ingelheim’s idarucizumab (Praxbind), the first product specifically targeted to reverse the effects of dabigatran (Pradaxa).

When health care providers were previously faced with the need for urgent reversal of dabigatran, there were few options available, and none of them were ideal in life-threatening situations.

These limited options included:

• Supportive therapy to allow the patient to clear the dabigatran (not a great option for a patient with life-threatening bleeding)
• Dialysis to assist the patient in clearing the drug (may be difficult to obtain access for dialysis catheters)
• Activate 4-factor prothrombin complex concentrate or recombinant factor VIIa to reverse the effects of the drug (off-label uses that made clinicians worry about thrombosis)

With the approval of idarucizumab, clinicians will have a more efficient tool to use for the reversal of dabigatran.

Here are 7 things pharmacists need to know before recommending the use of idarucizumab:

• Idarucizumab is a monoclonal antibody specifically targeted at dabigatran, meaning it won’t reverse the effects of other oral anticoagulants.
• Obtain an accurate medication history. Because idarucizumab only reverses dabigatran, it won’t be effective if the patient is taking another anticoagulant such as warfarin or a factor Xa inhibitor such as rivaroxaban, apixaban or edoxaban. To avoid a potential waste of resources, the patient’s use of dabigatran should be confirmed.
• Praxbind is indicated when reversal of the anticoagulant effects of dabigatran is needed for emergent surgery or urgent procedures and in life-threatening or uncontrolled bleeding, so it’s best to investigate whether these criteria are met. If there is no need for urgent reversal, then it may be better to withhold the drug and allow it to be cleared by the patient. Keep in mind that the elimination half-life of dabigatran is approximately 12 to 17 hours, on average.
• The dose of idarucizumab is 5 g. The product comes in 2 vials each containing 2.5 g/50 mL, which can be given as 2 separate infusions or as a bolus by giving both vials consecutively via syringe. Tthe anticoagulant effect of dabigatran was fully reversed in 89% of patients at 4 hours following administration of idarucizumab, according to the FDA. The current prescribing information states that there is limited data to support the administration of an additional vial of idarucizumab; however, in some patients, re-elevation of lab tests has occurred as dabigatran makes its way from the periphery back to the plasma. It’s prudent to make decisions based on patient response and clinical situation.
• Be wary of thrombosis. Pharmacists should work closely with the patient’s physician to determine whether and when anticoagulation should be restarted. The patient was taking dabigatran for a reason, and that reason will hold true after dabigatran is reversed.
• There are no contraindications listed in the prescribing information, but since this is a monoclonal antibody, there is the risk of an immunogenic reaction. The prescribing information also mentions the risk of serious adverse reaction in patients with hereditary fructose intolerance due to the sorbitol contained in the product.
• Pricing is currently not available, but it’s safe to say that this product probably won’t be cheap. Pharmacy and therapeutics committees will ultimately have to decide whether to add idarucizumab to the formulary, how much to keep, and what policies and procedures should govern its use.

References

• Praxbind [package insert]. Ridgefield, CT: Boehringer Ingelheim Pharmaceuticals, Inc; 2015. Accessed October 19, 2015.
• FDA. FDA approves Praxbind, the first reversal agent for the anticoagulant Pradaxa. Accessed October 19, 2015.