Betrixaban for Extended Venous Thromboembolism Prophylaxis in High-Risk Hospitalized Patients: Putting the APEX Results into Practice

An Update on Betrixaban, The Challenging Anticoagulant Agent for Extended Venous Thromboembolism Prophylaxis

ABSTRACT

Venous thromboembolism (VTE) is a prevalent yet preventable cause of death, particularly among hospitalized patients. Studies have shown that the risk of VTE remains high for up to 6 months after discharge, highlighting the need for extended thromboprophylaxis as a viable treatment approach. Despite the availability of several anticoagulant drugs such as vitamin K antagonists, heparinoids, rivaroxaban, apixaban, edoxaban, and dabigatran, none of them has received approval from the US Food and Drug Administration for long-term thromboprophylaxis. However, an emerging factor Xa inhibitor called betrixaban has shown promising results in Phase II and phase III trials, positioning itself as the first and only US Food and Drug Administration-approved anticoagulant for extended thromboprophylaxis in hospitalized patients after discharge. Betrixaban offers distinct pharmacological characteristics, including a long half-life, low renal excretion, and unique hepatic metabolism, making it an attractive option for various theoretical uses. Numerous articles have been published discussing the safety and efficacy of betrixaban, all of which have emphasized its usefulness and practicality. However, there has been limited discussion regarding its weaknesses and areas of ambiguity. Therefore, this article aimed to explore the challenges faced during the approval process of betrixaban and provide a comprehensive review of the literature on its advantages and disadvantages as a long-term prophylaxis approach for VTE. Furthermore, we aim to identify the ambiguous points that require further investigation in future studies.

A Review on the Use of Reversal Agents of Direct Oral Anticogulant Drugs in Case of Gastrointestinal Bleeding

BACKGROUND

Major bleeding is a life-threatening condition and a medical emergency with high mortality risk. It is often the complication of anticoagulant's intake. Anticoagulants are commonly used for the prevention and treatment of thrombotic events. The standard therapy with vitamin K antagonist (warfarin) has been frequently replaced by direct oral anticoagulants (DOACs). The latter agents (rivaroxaban, apixaban, edoxaban, dabigatran, and betrixaban) showed better efficacy and safety compared to standard warfarin treatment and they are recommended for the reduction of ischemic stroke. Literature data reported a high risk of gastrointestinal bleeding with DOACs, in particular with dabigatran and rivaroxaban. In case of life-threatening gastrointestinal bleeding, these patients could benefit from the use of reversal agents.

METHODS

We performed an electronic search on PUBMED of the literature concerning reversal agents for DOACs and gastrointestinal bleeding in the Emergency Department from 2004 to 2020.

AIM

This review summarizes the current evidence about three reversal agents idarucizumab, andexanet alfa and ciraparantag, and the use of the first two in the emergency setting in patients with active major bleeding or who need urgent surgery which physicians indicate for a better management approach in order to increase patient's safety.

CONCLUSION

Although these agents have been marketed for five years (idarucizumab) and two years (andexanet alfa) respectively, and despite guidelines considering antidotes as first-line agents in treating life-threatening hemorrhage when available, these antidotes seem to gain access very slowly in the clinical practice. Cost, logistical aspects and need for plasma level determination of DOAC for an accurate therapeutic use probably have an impact on this phenomenon.. An expert multidisciplinary bleeding team should be established so as to implement international guidelines based on local resources and organization.

The current place of direct oral anticoagulants in the prevention/treatment of venous thromboembolism

Venous thromboembolism (VTE; includes deep venous thrombosis, DVT, and pulmonary embolism, PE) represents the third most common acute cardiovascular syndrome. Contemporary VTE management comprises primary prevention in high-risk patients, treatment of established VTE, and prevention of its recurrence (secondary prevention). Anticoagulants are the basis of VTE pharmacological prophylaxis and treatment. For several decades, parenteral (heparin and low-molecular-weight heparins, LMWHs) and oral anticoagulants (vitamin K antagonists, VKAs) have been the cornerstone of VTE prevention/treatment. The introduction of direct oral anticoagulants (DOACs: thrombin inhibitor dabigatran and Xa inhibitors rivaroxaban, apixaban, edoxaban, and betrixaban) markedly improved the management of VTE by overcoming many disadvantages of conventional anticoagulants. For primary VTE prevention in patients after total hip/knee arthroplasty, rivaroxaban, apixaban, and dabigatran are preferred over LMWHs, due to comparable efficacy and safety, but favourable acceptability (avoided everyday injections). In other high-risk populations (other surgical patients, acutely ill medical patients), LMWHs are still the recommended option. Betrixaban is currently the only DOAC approved for VTE prophylaxis in medically ill patients during and after hospitalization. For acute VTE treatment and secondary prevention, DOACs (rivaroxaban, apixaban, edoxaban, and dabigatran) are recommended as the first-line therapy in the general population. DOACs proved to be similarly effective but safer than VKAs. In some specific populations, DOACs also seem to be advantageous over conventional treatment (patients with renal impairment, elderly, long-term secondary prevention in cancer patients). Currently, there is no data from randomized head-to-head comparative studies between the DOAC classes or representatives so the choice is made mainly according to patient characteristics and pharmacokinetic properties of the drug.