BACKGROUND
Andexanet alfa is a modified recombinant inactive form of human factor Xa developed for reversal of factor Xa inhibitors.
METHODS
We evaluated 352 patients who had acute major bleeding within 18 hours after administration of a factor Xa inhibitor. The patients received a bolus of andexanet, followed by a 2-hour infusion. The coprimary outcomes were the percent change in anti-factor Xa activity after andexanet treatment and the percentage of patients with excellent or good hemostatic efficacy at 12 hours after the end of the infusion, with hemostatic efficacy adjudicated on the basis of prespecified criteria. Efficacy was assessed in the subgroup of patients with confirmed major bleeding and baseline anti-factor Xa activity of at least 75 ng per milliliter (or ≥0.25 IU per milliliter for those receiving enoxaparin).
RESULTS
Patients had a mean age of 77 years, and most had substantial cardiovascular disease. Bleeding was predominantly intracranial (in 227 patients [64%]) or gastrointestinal (in 90 patients [26%]). In patients who had received apixaban, the median anti-factor Xa activity decreased from 149.7 ng per milliliter at baseline to 11.1 ng per milliliter after the andexanet bolus (92% reduction; 95% confidence interval [CI], 91 to 93); in patients who had received rivaroxaban, the median value decreased from 211.8 ng per milliliter to 14.2 ng per milliliter (92% reduction; 95% CI, 88 to 94). Excellent or good hemostasis occurred in 204 of 249 patients (82%) who could be evaluated. Within 30 days, death occurred in 49 patients (14%) and a thrombotic event in 34 (10%). Reduction in anti-factor Xa activity was not predictive of hemostatic efficacy overall but was modestly predictive in patients with intracranial hemorrhage.
CONCLUSIONS
In patients with acute major bleeding associated with the use of a factor Xa in-hibitor, treatment with andexanet markedly reduced anti-factor Xa activity, and 82% of patients had excellent or good hemostatic efficacy at 12 hours, as adjudicated according to prespecified criteria. (Funded by Portola Pharmaceuticals; ANNEXA-4 .)
In patients with MS, DSE is a safe and highly feasible stress test. A DSE-MG > or =18 mm Hg identifies a subgroup of high-risk patients in whom a more aggressive approach may be warranted; on the other hand, patients with a DSE-MG <18 mm Hg predicts an uneventful clinical course and may justify a more conservative strategy.
INTRODUCTION:
Andexanet alfa is a recombinant modified human Factor Xa (FXa) decoy protein developed to reverse the anticoagulant effect of FXa inhibitors.
METHODS:
ANNEXA-4 was a prospective single-arm study of andexanet alfa in patients with acute major bleeding while taking a FXa inhibitor. Patients with major gastrointestinal (GI) bleeding were eligible if they had (1) signs/symptoms of hemodynamic compromise or (2) bleeding associated with a hemoglobin (Hb) drop ≥2 g/dL or baseline Hb ≤8 g/dL. Upon enrollment, patients were treated with one of two andexanet dosing regimens based on the type, timing, and dose of the most recent inhibitor intake. Efficacy was evaluated in all patients who met the bleeding criteria above and had a baseline anti-FXa activity ≥75 ng/mL (≥0.25 IU/mL for enoxaparin). Co-primary endpoints were the change in anti-FXa activity and the achievement of hemostasis, as adjudicated by an independent committee, at 12 hours after andexanet treatment. Hemostasis was defined as: excellent if the red blood cell transfusion-corrected Hb at 12 hours was ≤10% lower than baseline, good if Hb was 10-20% lower, and poor/none if Hb was >20% lower.
RESULTS:
Of 352 patients enrolled in the study, 90 had GI bleeding, of whom 62 were included in the efficacy analysis. Median age was 76 years (range 24-95); 51 (57%) were male. Patients were receiving rivaroxaban (n = 44), apixaban (n = 5), and edoxaban (n = 3) at study entry. Bleeding location was identified in 48 patients (upper n=27, lower n = 21) and unknown in 42 patients. 66 (73%) patients had some evidence of hemodynamic compromise, including 38 (42%) patients with hypotension. Mean Hb at the time of dosing was 4.9 ± 1.4 g/dL. In patients taking rivaroxaban, the baseline anti-FXa activity was 267 ± 168.5 ng/mL and the percent reduction with andexanet was 94% (95%CI 89-96). In apixaban patients, the baseline anti-FXa activity was 244 ± 215.0 ng/mL and the percent reduction with andexanet was 92% (95%CI 88-95). Excellent/good hemostasis was achieved in 85% of evaluable patients. 58 (94%) of 62 patients received red blood cell transfusions, 3 (5%) received platelet transfusion, and 2 (3%) received a coagulation factor product. 30-day rates of thrombosis and death were 6% and 13%, respectively.
CONCLUSION:
In patients with major GI bleeding treated with andexanet, a high rate of effective hemostasis was achieved. The thrombosis and mortality rates are consistent with prior studies in this patient population.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.