Andexanet alfa in the treatment of acute major bleeding related to apixaban and rivaroxaban: a profile of its use in the USA

Andexanet alfa therapy showed No increased rate of thromboembolic events in spontaneous intracranial hemorrhage patients: A multicenter electronic health record study

•Intracranial hemorrhage accounts for two out of every three major intracranial hemorrhages.•Systemic anticoagulation is routinely prescribed for prevention of cerebrovascular accidents.•The FDA approved Andexanet alfa to treat life-threatening bleeding.•Andexanet alfa relationship to outcomes requires further investigation.

Costs and Healthcare Resource Utilization Associated with Idarucizumab or Andexanet Alfa Oral Anticoagulant Reversal in Patients Hospitalized with Life-Threatening Bleeds

Purpose: To assess costs and healthcare resource utilization (HCRU) associated with the use of idarucizumab for the reversal of dabigatran and andexanet alfa for the reversal of direct oral Factor Xa inhibitors. Methods: This retrospective study utilizing Premier Healthcare Database (PHD) included patients aged ≥18 years on direct oral anticoagulants (DOACs) who experienced life-threatening bleeds, discharged from the hospital during 5/1/2018–6/30/2019, and received idarucizumab or andexanet alfa. Inverse of treatment probability weighting (IPTW) method was used to balance patient and clinical characteristics between treatment cohorts. Results: Idarucizumab patients were older than andexanet alfa patients (median age 81 vs 77 years; p < 0.001), and less likely to experience intracranial hemorrhage (ICH) (37.1%vs 73.8%; p  =  0.001). After IPTW adjustment, idarucizumab patients incurred lower mean total hospital costs ($30,413  ±  $33,028 vs $44,477  ±  $30,036; p < 0.001),and mean intensive care unit (ICU) cost ($25,114  ±  $30,433 vs $43,484  ±  $29,335; p < 0.001). Conclusions: Anticoagulant reversal therapy with idarucizumab was associated with significantly lower adjusted mean total hospital and ICU costs compared with andexanet alfa. However, a higher prevalence of ICH bleeds was noted in the andexanet alfa group. Trial Registration: Not applicable.

Efficacy and Safety of Andexanet Alfa for Bleeding Caused by Factor Xa Inhibitors: A Systematic Review and Meta-Analysis

Direct oral anticoagulants (DOAC) including factor Xa inhibitors are associated with bleeding events which can lead to severe morbidity and mortality. Reversal agents like andexanet alfa (AA) and 4F-PCC (Four-factor prothrombin concentrate complex) are available for treating bleeding that occurs with DOAC therapy but a comparison on their efficacy is lacking. In this study, we analyzed the efficacy and safety of patients treated with andexanet alfa for bleeding events from DOAC. Databases were searched for relevant studies where AA was used to determine efficacy and safety in bleeding patients who were on factor Xa inhibitors. Published papers were screened independently by two authors. RevMan 5.4 (The Cochrane Collaboration, 2020) was used for data synthesis. Odds ratio (OR) and mean difference (MD) was used to estimate the outcome with a 95% confidence interval (CI). Among 1245 studies were identified after a thorough database search and three studies were included for analysis. AA resulted in lower odds of mortality compared to 4F- PCC (OR, 0.37; 95% CI, 0.20-0.71) among patients with intracerebral hemorrhage. There was no difference in thrombotic events between patients receiving AA and 4F-PCC (OR, 2.40; 95% CI, 0.36-15.84). No differences in length of hospital stay and intensive care unit (ICU) stay were seen between patients receiving AA and 4F-PCC. In conclusion, andexanet alfa reduced in-hospital mortality in patients who had bleeding due to factor Xa inhibitors compared to 4F-PCC. However, there were no differences in thrombotic events, length of ICU, and hospital stay between patients treated with AA and 4F-PCC.

Direct-Acting Oral Anticoagulants in Atrial Fibrillation: What's New in the Literature

Atrial fibrillation (AF) is considered the most common sustained cardiac arrhythmia, and it is associated with a significant risk of adverse events, especially ischemic stroke. Oral anticoagulation is the cornerstone for stroke prevention in AF; for many years, only vitamin K antagonists were used for this purpose, with an absolute risk reduction >60%. However, these agents have limitations, such as narrow therapeutic margins and drug-food and drug-drug interactions. More recently, 4 direct-acting oral anticoagulants (DOACs)-non-vitamin K antagonists-have become available for patients with AF: dabigatran, rivaroxaban, apixaban, and edoxaban. In addition to a comparable efficacy to warfarin in large randomized controlled trials, DOACs were found to promote a lower risk of intracranial bleeding. The strategic dosage and lack of need for periodic prothrombin-time testing make their use attractive, especially for primary or secondary prevention of stroke in older adults. Furthermore, among patients with AF presenting with acute coronary syndrome or undergoing percutaneous coronary intervention, apixaban is associated with a reduction in serious bleeding events when compared with warfarin. On the other hand, there is no evidence of benefit of DOACs in patients with mechanical prosthetic valves or moderate/severe mitral stenosis. Furthermore, the suitability of DOACs in patients with liver disease is still poorly understood, and their safety in patients requiring renal replacement therapy remains uncertain. This review provides an overview of the main trials of DOACs, their pharmacology and safety profile, clinical implications, and best indications in light of the current evidence.

[Osteosynthetic treatment of proximal femoral fractures: the timing of treatment is delayed in cases of pre-existing anticoagulation : Results of the data of external inpatient quality assurance from North Rhine-Westphalia with 24,786 cases within the framework of using secondary data]

Hintergrund und Fragestellung

Proximale Femurfrakturen stellen mit ca. 100.000 Betroffenen/Jahr in Deutschland ein häufiges Krankheitsbild dar. Durch eine zeitnahe Versorgung (<24 h) konnte die Mortalität erheblich gesenkt werden. Ziele der Arbeit waren, die Prävalenz der Antikoagulation und hiermit assoziierte Komplikationen bei osteosynthetisch versorgter, proximaler Femurfraktur und deren Impact auf die präoperative Verweildauer zu analysieren und Potenziale zum optimalen perioperativen Gerinnungsmanagements aufzuzeigen.

Material und Methoden

Die Daten der externen vergleichenden Qualitätssicherung Nordrhein-Westfalen für die Jahre 2015 und 2016 wurden ausgewertet. Dabei wurden ausschließlich Fälle analysiert, bei denen eine hüftgelenknahe Femurfraktur osteosynthetisch versorgt wurde. Insgesamt wurden 24.786 Fälle hüftgelenknaher Femurfrakturen in die Studie eingeschlossen.

Ergebnisse

Von den Patienten mit einer antithrombotischen Dauertherapie (ATDT) wurden in der größten Subgruppe mit ASS-Medikation (n = 4005) 17 %, in der zweitgrößten Gruppe mit Vitamin-K-Antagonisten-Einnahme (n = 2157) 44,6 % und in der drittgrößten Gruppe mit Einnahme von direkten oralen Antikoagulanzien (DOAKs, n = 994) 18,2 % verzögert operiert.

Schlussfolgerungen

Das größte Potenzial zur Verkürzung der präoperativen Verweildauer ergibt sich in der Gruppe der Patienten, die ASS (17 % auffällig) oder einen Vitamin-K-Antagonisten (VKA, 44,6 % auffällig) einnehmen. Eine Antagonisierung der Wirkung von VKA lässt sich innerhalb kurzer Zeit durch die Gabe von Prothrombinkomplex (PPSB) erreichen. Auch unter der Einnahme von DOAKs muss das noch gängige Prozedere einer verzögerten operativen Versorgung kritisch hinterfragt werden. Die Etablierung eines Gerinnungsmanagements ist zu fordern. Neben der medizinischen Intervention (Gabe von Antidota) müssen Strukturen geschaffen werden, die eine zeitnahe Versorgung ermöglichen.

Institutional Experience of Using Andexanet Alfa

Given their ease of use, safety, and efficacy, direct-acting oral anticoagulants (DOACs) are nowadays widely used in patients with atrial fibrillation or venous thromboembolism, with or without an association with malignancy. Andexanet alfa (andexanet) is a recombinant modified human factor Xa decoy protein that reverses the inhibition of factor Xa. After Food and Drug Administration (FDA) approval in May 2018, andexanet has been used for life-threatening bleeding in patients treated with apixaban or rivaroxaban.

In this article, we present a single institutional retrospective review of patients receiving andexanet alfa at Guthrie Robert Packer Hospital. A total of four patients in a period of 10 months received andexanet for intracranial bleeding, 50% (2) had excellent hemostasis, 30 days mortality was 75% (3), and 25% (1) had a thromboembolic event. Anticoagulation was never started in all patients. This review tends to show the real-world utilization data of andexanet in a community hospital setting.

Reversal of Factor Xa Inhibitors by Andexanet Alfa May Increase Thrombogenesis Compared to Pretreatment Values

Recombinant coagulation factor Xa (FXa), inactivated Zh-zo, also known as andexanet alfa (AA), is a modified version of human FXa that has been developed to neutralize FXa inhibitors. We studied the reversal effect of AA for these inhibitors in various anticoagulant and thrombin generation (TG) assays. Individual aliquots of normal human plasma containing 1 µg/mL of apixaban, betrixaban, edoxaban, and rivaroxaban, were supplemented with saline or AA at a concentration of 100 µg/mL. Clotting profiles include prothrombinase-induced clotting time, activated partial thromboplastin time, and prothrombin time. Factor Xa activity was measured using an amidolytic method. Thrombin generation was measured using a calibrated automated thrombogram. Differential neutralization of all 4 anticoagulants was noted in the activated clotting time and other clotting tests. The FXa activity reversal profile varied with an observed decrease in apixaban (22%), betrixaban (56%), edoxaban (28%), and rivaroxaban (49%). Andexanet alfa also led to an increased TG in comparison to saline. The peak thrombin was higher (40%), area under the curve (AUC) increased (15%), whereas the lag time (LT) decreased (17%). Andexanet alfa added at 100 µg/mL to various FXa supplemented systems resulted in reversal of the inhibitory effects, restoring the TG profile; AUC, LT, and peak thrombin levels were comparable to those of unsupplemented samples. Andexanet alfa is capable of reversing anti-Xa activity of different oral FXa inhibitors but overshoots thrombogenesis in both the saline and FXa inhibitor supplemented systems. The degree of neutralization of Xa inhibitor is specific to each agent.

Thrombin Generation Profile in Various Lymphoma Sub-Groups and Its Augmentation by Andexanet Alfa

The prevalence of thrombosis in lymphoma patients is reportedly high and ranges from 3-10%. Vascular malfunction and inflammatory processes further contribute to the thrombotic activation process in these patients. Andexanet alfa (AA) is an antidote for factor Xa inhibitors and its usage has been reported with thrombotic complications. This study was designed to compare the effect of AA on the thrombin generation (TG) potential. Blood samples from 78 patients with confirmed diagnosis of non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL) and Chronic lymphocytic leukemia (CLL) were collected from the University of Belgrade Clinic, Serbia. Normal human plasma (NHP) was used for referencing purposes. Individual samples were supplemented with AA at 100 ug/ml. TG studies were carried out using a commercially available fluorogenic substrate method. TG parameters such as peak thrombin (PT), lag time (LT) and area under the curve (AUC) were compiled. Cumulatively, lymphoma patients showed an increase in LT compared to NHP which decreases with AA. The PT and AUC levels were decreased compared to NHP and increases with AA. Upon sub-grouping of lymphoma patients, PT levels for all sub-groups were increased with AA. The AUC values increased for HL and NHL and decreased for CLL with AA. Variations in lag time were noted in all 3 sub-groups. Lymphoma represents a heterogenous group of patients where both the hypercoagulable state and inflammatory responses simultaneously occur. Increased thrombin generation in post AA supplemented samples suggest that the use of this agent may potentially be associated with thrombotic complications.

Andexanet alfa for reversal of factor Xa inhibitor-associated anticoagulation

Background:

Review of clinical data on andexanet alfa for the reversal of factor Xa (FXa) inhibitor associated anticoagulation.

Data sources:

In the present review, we identified articles via PubMed using the combined keywords andexanet alfa, apixaban, enoxaparin, edoxaban, and rivaroxaban. Additional online searches via PubMed, Google Scholar, and Lexicomp were conducted for both prescribing and cost information. Portola Pharmaceuticals was contacted for information used for United States Food and Drug Administration approval of andexanet alfa.

Study selection and data extraction:

English-language clinical trials and reviews published between January 2008 and April 2019 were included for review. Bibliographies of selected articles were reviewed manually for relevant publications, focusing on reversal strategies for apixaban, enoxaparin, edoxaban, or rivaroxaban associated anticoagulation using andexanet alfa. Review articles were excluded.

Data synthesis:

The safety and tolerability of andexanet alfa were evaluated in one phase I, two phase II, and one phase III clinical trials. The use of andexanet alfa for reversing FXa inhibitor-associated anticoagulation were evaluated in the phase III ANNEXA-4 study.

Conclusions:

Studies evaluating laboratory parameters for coagulation show that andexanet alfa rapidly neutralizes the anticoagulant effects of apixaban, enoxaparin, edoxaban, and rivaroxaban. Clinical studies show that andexanet alfa improves markers related to coagulation, and reverses major bleeding in healthy volunteers and patients with life-threatening bleeding. Interruption of anticoagulation may result in thromboembolic and ischemic events. The use of andexanet alfa requires close monitoring for signs and symptoms of thromboembolic events, ischemic events, and cardiac arrest. Furthermore, anticoagulation should be resumed following the administration of andexanet alfa as soon as medically appropriate.

Reversal agents for direct oral anticoagulants: considerations for hospital physicians and intensivists

Direct oral anticoagulants (DOACs) include dabigatran etexilate, a direct thrombin inhibitor, and specific inhibitors of activated coagulation factor X (FXa; e.g. apixaban, betrixaban, edoxaban, rivaroxaban). DOACs are associated with lower rates of major and fatal bleeding events compared with warfarin. Clinicians may need to achieve rapid reversal of anticoagulation effects of the DOACs in an emergency setting. Idarucizumab and andexanet alfa, which reverse the anticoagulant effects of dabigatran and FXa inhibitors, respectively, are DOAC reversal agents available in the US. Other reversal agents (e.g. ciraparantag for heparins, DOACs) are in development. Alternative nonspecific agents (e.g. fresh frozen plasma, prothrombin complex concentrate) are available. Nonspecific prohemostatic agents can counteract the anticoagulant action of DOACs in emergency situations, when specific reversal agents are unavailable. However, specific reversal agents are efficacious and safe and should be preferred when available. In this review, we discuss practical issues in the initiation of DOAC therapy, situations where reversal may be needed, coagulation assays, reversal agents, and post-reversal complications in the context of published evidence and guidelines.