Beginning to Understand the Cost-effectiveness of Andexxa

**Introduction:** Tens of thousands of patients die of major life-threatening bleeds every year while taking direct factor Xa inhibitors, a class of anticoagulant medications that until now had no reversal agent. In May 2018, the US Food and Drug Administration approved andexanet alfa (Andexxa), the first known reversal agent for a subset of direct factor Xa inhibitors. It has been reported to substantially reduce mortality rates for patients who experience a major bleed while taking rivaroxaban or apixaban. Andexxa is costly, however, ranging between US $24,750 and $49,500 for treatment. **Methods:** To explore the cost-effectiveness of Andexxa, a Markov model was generated using existing Andexxa trial data and related literature. Multiple 1-way and 2-way sensitivity analyses were also constructed to delineate the impact Andexxa would need to have on mortality rates and health-related quality of life to meet the willingness-to-pay thresholds ranging between $50,000 and $150,000. The model included a hypothetical cohort of patients aged 65 years at an increased risk of stroke due to nonvalvular atrial fibrillation and with no contraindication to anticoagulation. **Results:** The Markov model showed that the incremental cost-effectiveness ratio of Andexxa over the standard of care is $211,056 for an intracranial hemorrhage and $40,718 for a gastrointestinal bleed. Sensitivity analyses further indicated that while Andexxa may be cost-effective to treat gastrointestinal bleeds, medication trial data will likely need to show significant impact on a patient’s quality of life and relative risk of death following an intracranial bleed to be cost-effective. **Discussion:** Although the application of these findings is restricted due to limited trial data, beginning to understand the cost-effectiveness of Andexxa provides policymakers important insight into the economic value of the intervention.