Cost-Effectiveness of Betrixaban Compared with Enoxaparin for Venous Thromboembolism Prophylaxis in Nonsurgical Patients with Acute Medical Illness in the United States

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.

Use of Health Technology Assessment for the Continued Funding of Health Technologies: The Case of Immunoglobulins for the Management of Multifocal Motor Neuropathy

INTRODUCTION

Funding decisions for many health technologies occur without undergoing health technology assessment (HTA), in particular, without assessment of cost effectiveness (CE). Immunoglobulins in Australia are an interesting case study because they have been used for a long time for various rare disorders and their price is publicly available. Undertaking an HTA enables us to assess CE for an intervention for which there is limited clinical and economic evidence. This study presents a post-market review to assess the CE of immunoglobulins for the treatment of multifocal motor neuropathy (MMN) compared with best supportive care.

METHODS

A Markov model was used to estimate costs and quality-adjusted life-years (QALYs). Input sources included randomised controlled trials, single-arm studies, the Australian clinical criteria for MMN, clinical guidelines, previous Medical Services Advisory Committee (MSAC) reports and inputs from clinical experts. Sensitivity analyses were conducted to assess the uncertainty and robustness of the CE results.

RESULTS

The cost per patient of treating MMN with immunoglobulin was AU$275,853 versus AU$26,191when no treatment was provided, with accrued QALYs of 6.83 versus 6.04, respectively. The latter translated into a high incremental cost-effectiveness ratio (ICER) of AU$317,552/QALY. The ICER was most sensitive to the utility weights and the price of immunoglobulins. MSAC advised to continue funding of immunoglobulins on the grounds of efficacy, despite the high and uncertain ICER.

CONCLUSIONS

Beyond the ICER framework, other factors were acknowledged, including the high clinical need in a patient population for which there are no other active treatments available. This case study highlights the challenges of conducting HTA for already funded interventions, and the efficiency trade-offs required to fund effective high-cost therapies in rare conditions.

Investigating Betrixaban Maleate drug degradation profiles, isolation and characterization of unknown degradation products by mass-triggered preparative HPLC, HRMS, and NMR

Betrixaban Maleate, a novel oral, once-daily factor Xa inhibitor drug substance, was subjected to stress testing under a wide range of degradation conditions, including acidic hydrolysis, alkaline hydrolysis, oxidative, thermal, and photolytic, to determine its inherent stability. The drug was biodegradable in acidic and alkaline environments, and three new degradation products were identified. Two degraded products are formed in an acidic environment, while the third is in alkaline conditions. The three degradants were identified using UPLC-ESI/MS and isolated using mass-triggered preparative HPLC, and their structures were unambiguously elucidated using HRMS and 2D NMR techniques. Based on spectral and chromatographic data, it was firmly proven that these distinct degradation products were the betrixaban chemical's hydrolysis components. The formation of the degradants has been hypothesized through several possible mechanisms.

Current Opinion on the use of Direct Oral Anticoagulants for the Prophylaxis of Venous Thromboembolism among Medical Inpatients

Venous thromboembolism (VTE) is a known cause of morbidity and mortality, especially among acutely ill medical patients. Although VTE prophylaxis is part of post-discharge clinical care in surgical patients, there is controversy regarding its use in acutely ill medical patients and the current guideline statements suggest against its routine use. Recent clinical trials (APEX, MAGELLAN and MARINER) compared the safety and efficacy of direct oral anticoagulants (including betrixaban and rivaroxaban) with the standard of the care, enoxaparin, to identify the risk–benefit tradeoff. In this review, we summarized the key findings from these trials and substudies and recent updates in society guidelines regarding VTE prevention. In addition, we discussed the potential barriers, cost-effectiveness, and COVID-19 with respect to the implementation of extended-duration or post-discharge usage of direct oral anticoagulants.

Release characteristics of enoxaparin sodium-loaded polymethylmethacrylate bone cement

BACKGROUND

This study aimed to prepare the polymethylmethacrylate (PMMA) bone cement release system with different concentrations of enoxaparin sodium (ES) and to investigate the release characteristics of ES after loading into the PMMA bone cement.

METHODS

In the experimental group, 40 g Palacos®R PMMA bone cement was loaded with various amount of ES 4000, 8000, 12,000, 16,000, 20,000, and 24,000 AXaIU, respectively. The control group was not loaded with ES. Scanning electron microscopy (SEM) was used to observe the surface microstructure of the bone cement in the two groups. In the experiment group, the mold was extracted continuously with pH7.4 Tris-HCL buffer for 10 days. The extract solution was collected every day and the anti-FXa potency was measured. The experiment design and statistical analysis were conducted using a quantitative response parallel line method.

RESULTS

Under the SEM, it was observed that ES was filled in the pores of PMMA bone cement polymer structure and released from the pores after extraction. There was a burst effect of the release. The release amount of ES on the first day was 0.415, 0.858, 1.110, 1.564, 1.952, and 2.513, respectively, from the six groups with various ES loading amount of 4000, 8000, 12,000, 16,000, 20,000, and 24,000 AXaIU, all reaching the peak of release on the first day. The release decreased rapidly on the next day and entered the plateau phase on the fourth day.

CONCLUSION

The prepared ES-PMMA bone cement has high application potential in orthopedic surgery. ES-PMMA bone cement shows good drug release characteristics. The released enoxaparin sodium has a local anti-coagulant effect within 24 h after application, but it will not be released for a long time, which is complementary to postoperative anti-coagulation therapy.

Estimation of Acutely Ill Medical Patients at Venous Thromboembolism Risk Eligible for Extended Thromboprophylaxis Using APEX Criteria in US Hospitals

Major medical illnesses place patients at risk of venous thromboembolism (VTE). Some risk factors including age ≥75 years or history of cancer place them at increased risk of VTE that extends for at least 5 to 6 weeks following hospital admission. Betrixaban thromboprophylaxis is now approved in the United States for this indication. We estimated the annual number of acutely ill medical patients at extended risk of VTE discharged from US hospital. Major medical illnesses (stroke, respiratory failure/chronic obstructive pulmonary disease, heart failure, pneumonia, other infections, and rheumatologic disorders) and 2 common risk factors for extended VTE risk, namely, age ≥75 years and history of cancer (active or past) were examined in 2014 US hospital discharges using the first 3 discharge diagnosis codes in the National Inpatient Sample (database of acute-care hospital discharges from the US Agency for Health Care Quality and Research). In 2014, there were 20.8 million discharges with potentially at risk of nonsurgical-related VTE. Overall, 7.2 million (35%) discharges corresponded to major medical illness that warranted thromboprophylaxis according to 2012 American College of Chest Physicians (ACCP) guideline. Among them, 2.79 million were aged ≥75 years and 1.36 million had a history of cancer (aged 40-74 years). Overall, 3.48 million discharges were at extended risk of VTE. Many medical inpatients at risk of VTE according to 2012 ACCP guideline might benefit from the awareness of continuing risk and some of these patients might benefit from extended thromboprophylaxis, depending on the risk of bleeding and comorbidities.