Andexanet alfa for the reversal of anticoagulation: Dutch practice data

Background: Andexanet alfa is a reversal agent for factor Xa (FXa) inhibitors (rivaroxaban and apixaban) and is available for the treatment of severe FXa inhibitor-associated bleeding. However, an increase in thrombotic events after administration has been reported. Objectives: This multicenter Dutch observational study aimed to provide insights into the characteristics, usage patterns, and clinical outcomes of the Dutch patient population treated with andexanet alfa. Methods: We included all patients treated with on- and off-label andexanet alfa from 6 of the 11 hospitals in the Netherlands that prescribed andexanet alfa between June 2019 and December 2023. Data were collected by LOGEX, a Dutch healthcare data company, using healthcare administrative data and questionnaires completed by clinicians at participating centers. Patient characteristics, details related to andexanet alfa administration, and 30-day clinical outcomes, including thrombotic events and all-cause mortality, were collected. Results: A total of 217 patients received andexanet alfa, including 192 treated on-label and 25 off-label. In the on-label group, the median age was 77 years (IQR, 69-82 years), and intracranial hemorrhage was the most common indication for reversal (61%). Most patients received a low dose (≤1000 mg) and were administered andexanet alfa within 4 hours of hospital admission (79%). The overall 30-day cumulative incidence of thrombotic events was 4.6%, and no thrombotic events occurred after anticoagulation was reinitiated. All-cause mortality was 34%, with similar rates between the on- and off-label groups. Conclusion: Andexanet alfa was primarily prescribed for the reversal of FXa inhibitors in patients with intracerebral hemorrhage. We observed a lower incidence of thrombotic events than reported in clinical trials.