Comparison of the phase III clinical trial designs of novel oral anticoagulants versus warfarin for the treatment of nonvalvular atrial fibrillation: implications for clinical practice

Generic Methods for Simultaneous Analysis of Four Direct Oral Anticoagulants in Human Plasma and Urine by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

The new direct oral anticoagulants (DOACs) are increasingly used to treat and prevent thromboembolic disorders, and monitoring concentrations may be valuable in some special scenarios to prevent clinical adverse events. This study aimed to develop generic methods for the rapid and simultaneous analysis of four DOACs in human plasma and urine. Protein precipitation and one-step dilution were used to prepare the plasma and urine; the extracts were injected to ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for analysis. Chromatographic separation was performed on an Acquity™ UPLC BEH C₁₈ column (2.1 × 50 mm, 1.7 μm) with gradient elution of 7 min. A triple quadrupole tandem mass spectrometer with an electrospray ionization source was employed to analyze DOACs in a positive ion mode. The methods showed great linearity in the plasma (1~500 ng/mL) and urine (10~10,000 ng/mL) for all analytes (R² ≥ 0.99). The intra- and inter-day precision and accuracy were within acceptance criteria. The matrix effect and extraction recovery were 86.5~97.5% and 93.5~104.7% in the plasma, while 97.0~101.9% and 85.1~99.5% in the urine. The stability of samples during the routine preparation and storage were within the acceptance criteria of less than ±15%. The methods developed were accurate, reliable, and simple for the rapid and simultaneous measurement of four DOACs in human plasma and urine, and successfully applied to patients and subjects with DOACs therapy for anticoagulant activity assessment.

Consensus in cardiology on non-vitamin-K oral anticoagulants for patients with atrial fibrillation

Introduction: Non-vitamin-K oral anticoagulants (NOACs) are known to have advantages over vitamin K antagonists (VKAs) for patients with atrial fibrillation (AF). However, more than half of patients are still treated with VKAs. The absence of direct comparisons amongst NOACs and the insufficient evidence in some clinical situations could explain, at least in part, this predominance of VKAs. The aims of our study were: 1) to analyze the opinion of an expert panel on the role of NOACs in different clinical scenarios; 2) to elaborate specific consensus recommendations for the management of NOACs for each one of these situations.Patients and methods: An online survey was created covering distinct aspects of the use of oral anticoagulants in various clinical settings. A two-round modified Delphi approach was used.Results: Forty-eight experts responded to the survey. Consensus was reached on 58% (48/83) of the items. The panelists concluded that the term non-valvular AF should be avoided. In most clinical settings NOACs were preferred over VKAs. Once daily NOACs were preferred in elderly patients to improve therapeutic compliance and, in those over the age of 85, edoxaban could be the best choice. Edoxaban and apixaban were the favorites for patients with AF and moderate chronic kidney disease (CKD). In the case of patients on triple antithrombotic therapy due to AF and acute coronary syndrome (ACS) the lowest effective NOAC dose should be used.Conclusion: Our study emphasizes that there are several clinical circumstances in patients with AF requiring complex decisions about anticoagulation treatment and offers some recommendations based on the consensus reached by an expert panel.

Clinical Performance of Apixaban vs. Vitamin K Antagonists in Patients with Atrial Fibrillation Undergoing Direct Electrical Current Cardioversion: A Prospective Propensity Score-Matched Cohort Study

INTRODUCTION

Atrial fibrillation (AF) is associated with an increased risk of thromboembolic events.

OBJECTIVES

This study compared the long-term efficacy and safety of apixaban with that of uninterrupted vitamin K antagonist (VKA) therapy in patients with AF scheduled for transesophageal echocardiogram (TEE)-guided direct current cardioversion (DCC) from June 2014 to September 2016.

METHODS

We enrolled consecutive patients with persistent nonvalvular AF scheduled to undergo DCC. Patients received apixaban 5 mg or 2.5 mg twice daily (bid) or VKA at therapeutic doses for at least 3 weeks before and 4 weeks after DCC. All patients underwent anamnestic, clinical, electrocardiographic, and echocardiographic evaluation at each follow-up visit and were followed-up for 12 months. The primary efficacy endpoint was the composite of stroke/transient ischemic attack and systemic embolism. The primary safety endpoint was major bleeding.

RESULTS

After propensity score matching, comparative treatment groups comprised 182 (75.8%) patients receiving apixaban 5 mg bid and 182 receiving VKA. A low incidence of atrial thrombus (0.5%) at TEE was found in both groups. The acute cardioversion success rate was 86.1% in the apixaban group (156/181) and 83.9% in the VKA group (152/181). During the follow-up period, a similarly low incidence of thromboembolic events (1.1%) was reported in both groups; the bleeding safety profile tended to favor apixaban over VKA (1.1 vs. 1.6%; p = 0.3).

CONCLUSIONS

Newly initiated anticoagulation with apixaban in patients with nonvalvular AF scheduled for TEE-guided DCC seems to be as effective and safe as uninterrupted VKA therapy during 12 months of follow-up.

Anticoagulation Strategies in Patients With Cancer: JACC Review Topic of the Week

Patients with active cancer are at an increased risk of arterial and venous thromboembolism (VTE) and bleeding events. Historically, in patients with cancer, low molecular weight heparins have been preferred for treatment of VTE, whereas warfarin has been the standard anticoagulant for stroke prevention in patients with atrial fibrillation (AF). More recently, direct oral anticoagulants (DOACs) have been demonstrated to reduce the risk of venous and arterial thromboembolism in large randomized clinical trials of patients with VTE and AF, respectively, thus providing an attractive oral dosing option that does not require routine laboratory monitoring. In this review, we summarize available clinical trial data and guideline recommendations, and outline a practical approach to anticoagulation management of VTE and AF in cancer.

Practical perspectives on the use of non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with nonvalvular atrial fibrillation: A view from the Middle East and North Africa

Clinical guidelines for the prevention of stroke in patients with nonvalvular atrial fibrillation (NVAF) are available from several international cardiology associations. Patients with NVAF in the Middle East and North Africa (MENA) region present unique challenges and opportunities related to differences in geography, practice patterns, and patient demographics that are as yet unaddressed in practice guidelines. This review aims to offer a practical perspective on the management of NVAF in patients in MENA and draws on evidence-based guidelines as well as real-world evidence and expert opinion. The literature was searched for relevant original research articles, systematic reviews, meta-analyses, and guideline recommendations addressing the prevention of stroke in patients with NVAF with a focus on issues relevant to the MENA region. Guideline recommendations, best practices, and expert opinion were discussed and agreed on by a working group consisting of cardiologists from across the MENA region. The incidence of stroke secondary to atrial fibrillation in patients across the MENA region is higher than rates reported globally, and this might be attributed to a higher incidence of vascular risk factors and underuse of anticoagulants in patients in the MENA. The available evidence supports the established role of non-vitamin K antagonist oral anticoagulants (NOACs) in the prevention of stroke in patients with NVAF. There is a consistent body of clinical trial and real-world evidence supporting their efficacy for stroke prevention in NVAF, with more favorable bleeding risk profiles relative to vitamin K antagonists, such that guidelines now recommend the use of NOACs in preference over vitamin K antagonists. There are important opportunities to improve the management of NVAF outcomes for patients with NVAF by applying evidence-based guidelines for stroke prevention. Growing experience with NOACs in the MENA region will help guide patient selection and elucidate optimal dosing strategies to maximize the clinical benefits of the NOACs.

Clinical Prediction Model for Time in Therapeutic Range While on Warfarin in Newly Diagnosed Atrial Fibrillation

Background

Though warfarin has historically been the primary oral anticoagulant for stroke prevention in newly diagnosed atrial fibrillation (AF), several new direct oral anticoagulants may be preferred when anticoagulation control with warfarin is expected to be poor. This study developed a prediction model for time in therapeutic range (TTR) among newly diagnosed AF patients on newly initiated warfarin as a tool to assist decision making between warfarin and direct oral anticoagulants.

Methods and Results

This electronic medical record–based, retrospective study included newly diagnosed, nonvalvular AF patients with no recent warfarin exposure receiving primary care services through a large healthcare system in rural Pennsylvania. TTR was estimated as the percentage of time international normalized ratio measurements were between 2.0 and 3.0 during the first year following warfarin initiation. Candidate predictors of TTR were chosen from data elements collected during usual clinical care. A TTR prediction model was developed and temporally validated and its predictive performance was compared with the SAMe‐TT₂R₂ score (sex, age, medical history, treatment, tobacco, race) using R² and c‐statistics. A total of 7877 newly diagnosed AF patients met study inclusion criteria. Median (interquartile range) TTR within the first year of starting warfarin was 51% (32, 67). Of 85 candidate predictors evaluated, 15 were included in the final validated model with an R² of 15.4%. The proposed model showed better predictive performance than the SAMe‐TT₂R₂ score (R²=3.0%).

Conclusions

The proposed prediction model may assist decision making on the proper mode of oral anticoagulant among newly diagnosed AF patients. However, predicting TTR on warfarin remains challenging.

North American Thrombosis Forum, AF Action Initiative Consensus Document

The North American Thrombosis Forum Atrial Fibrillation Action Initiative consensus document is a comprehensive yet practical briefing document focusing on stroke and bleeding risk assessment in patients with atrial fibrillation, as well as recommendations regarding anticoagulation options and management. Despite the breadth of clinical trial data and guideline recommendation updates, many clinicians continue to struggle to synthesize the disparate information available. This problem slows the uptake and utilization of updated risk prediction tools and adoption of new oral anticoagulants. This document serves as a practical and educational reference for the entire medical community involved in the care of patients with atrial fibrillation.

Direct Oral Anticoagulants for the Prevention of Stroke in Patients with Nonvalvular Atrial Fibrillation: Understanding Differences and Similarities

The presence of atrial fibrillation (AF), the most common sustained cardiac arrhythmia, significantly increases the risk for stroke. Current guidelines recommend that the vitamin K antagonist warfarin or direct oral anticoagulants (DOACs), such as the approved direct thrombin inhibitor dabigatran and the approved direct factor Xa inhibitors apixaban, rivaroxaban, and edoxaban, should be used for thromboprophylaxis in patients with nonvalvular AF at risk for stroke or systemic embolic events (SEE). Warfarin, the mainstay of stroke prevention in AF, increases the risk of major bleeding. Furthermore, warfarin therapy comes with several limitations including frequent monitoring and the need for dose adjustments, unpredictable pharmacokinetics and pharmacodynamics, and the potential for significant drug-drug and food-drug interactions. The DOACs were developed to overcome these limitations while maintaining or surpassing warfarin's efficacy and safety profiles. All four DOACs have similar or better efficacy and safety compared with warfarin and are therefore valuable alternatives for the prevention of stroke and SEE in patients with nonvalvular AF. Understanding the subtle differences in the DOACs' pharmacology, phase 3 study designs, and trial outcomes will allow for a more tailored approach in selecting the right oral anticoagulant for each patient.

Target-specific oral anticoagulants: practice issues for the clinician

Venous thromboembolism and atrial fibrillation are among the most common cardiovascular disorders in the United States. For over 50 years, the standard of care has been anticoagulation with vitamin K antagonists. However, the numerous limitations of vitamin K antagonists led to the development of target-specific oral anticoagulants. Dabigatran, rivaroxaban, apixaban, and edoxaban have been shown to be as effective as warfarin in the treatment and prevention of venous thromboembolism and prevention of stroke in nonvalvular atrial fibrillation. This article compares the basic pharmacologic properties of these anticoagulants, reviews the data supporting their use, and discusses practical clinical issues including measurement of the anticoagulation effect, reversal strategies, and management of patients prior to surgery.

The Potential Role of Edoxaban in Stroke Prevention Guidelines

With the emergence of edoxaban, the oral factor Xa inhibitors now appear consolidated as the dominant class of novel oral anticoagulants (NOACs) for stroke prevention in non-valvular atrial fibrillation (AF). The oral factor Xa inhibitors do not require an adequate time in therapeutic range to be effective, presenting a potential advantage over the vitamin K antagonists (VKAs). Guidelines are changing to reflect the increased choice of anticoagulants and as clinicians move away from the VKAs towards the relative safety and efficacy of NOACs, they must consider which one offers the best therapy for their patient. The ENGAGE-AF study was the latest phase III trial to report on the safety and efficacy of a new factor Xa inhibitor relative to warfarin. Both edoxaban 60mg once daily, and edoxaban 30mg once daily were found to be non-inferior compared to warfarin for the prevention of ischaemic stroke and systemic embolism, being associated with significantly lower rates of major bleeding, intracranial haemorrhage and cardiovascular death. A two-tiered dosing option may present clinicians with a further element of choice for the individual patient.