Emerging therapeutic uses of direct-acting oral anticoagulants: An evidence-based perspective

Perceptions of patients and healthcare providers on patient education to improve oral anticoagulant management

RATIONALE AND OBJECTIVES

Education of patients is thought to be key to high-quality oral anticoagulant (OAC) medication management. Theoretically, improving patients' knowledge should improve their self-management skills and adherence. The study's objective was to explore the opinions of healthcare providers and patients on the desired content and format of patient education on OACs, in addition to perceived barriers to high-quality patient education.

METHODS

We applied qualitative descriptive methods in a focus group study on OAC management. Five focus group discussions were conducted in two health regions in Southwestern Ontario from 2017 to 2018 with 19 patients, 7 caregivers and 16 healthcare providers (physicians, nurses and pharmacists). During the focus groups, participants discussed their experiences with OAC education and made suggestions about the content and format for patient education on OACs. Transcripts were analysed using conventional content analysis.

RESULTS

We identified the five themes of patient education on OAC management: content of OAC education (rationale, risk and appropriate drug administration methods), the best times for providing OAC education (time of OACs initiation along with continuing education), preferred education delivery strategies (case management targeted patient information summaries from authoritative sources such as Thrombosis Canada and video education), patient and community pharmacist engagement in OAC education, and perceived barriers to optimal patient education (patients depending too much on their healthcare providers for advice, the limited time patients spend with healthcare providers, gaps in clear communication between providers and the lack of a nationally or provincially coordinated OAC management programme).

CONCLUSION

Our findings suggest that patients, caregivers and healthcare providers support the need for education on OACs, including for patients taking DOACs. Specific important content and proper education format are needed. The optimal combination of content, format, duration, timing and sources for OAC education requires further research.

Drug-Drug Interactions between Direct Oral Anticoagulants and Hepatitis C Direct-Acting Antiviral Agents: Looking for Evidence Through a Systematic Review

Background

Direct oral anticoagulants (DOACs), as substrates of cytochrome P450 (CYP) 3A4 and/or P-glycoprotein, are susceptible to drug–drug interactions (DDIs). Hepatitis C direct-acting antiviral agents (DAAs), via P-glycoprotein or CYP3A4 inhibition, may increase DOAC exposure with relevant bleeding risk. We performed a systematic review on DDIs between DOACs and DAAs.

Methods

Two reviewers independently identified studies through electronic databases, until 7 July 2020, supplementing the search by reviewing conference abstracts and the ClinicalTrials.gov website.

Results

Of 1386 identified references, four articles were finally included after applying the exclusion criteria. Three phase I clinical studies in healthy volunteers assessed interactions between dabigatran and glecaprevir/pibrentasvir, odalasvir/simeprevir, or sofosbuvir/velpatasvir/voxilaprevir, showing an increase in the dabigatran area under the concentration–time curve (AUC) by 138%, 103%, and 161%, respectively.

Conclusions

DOACs and DAAs are under-investigated for DDI risk. Real-world studies are needed to assess the clinical relevance of the pharmacokinetic interactions with dabigatran and describe the actual spectrum of possible DDIs between DAAs and other DOACs.

What are the Characteristics of Patients Experiencing Adverse Drug Reactions to Oral Anticogulants and How Can Such Reactions be Prevented?

INTRODUCTION

Oral anticoagulants, including vitamin K inhibitors (VKAs) and direct anticoagulants (DOACs) are important for preventing and treating thromboembolic diseases. However, they are not recommended for use in all patients due to negative side effects and adverse drug reactions (ADRs). Currently, there is a paucity of information about their use in real life. Therefore, the aim of this pilot study is to report on the rate of serious ADRs in oral anticoagulant users, determine patient characteristics associated with increased risk of ADRs, and identify possible management strategies for reducing risk of ADRs within a hospital setting.

METHODS

Patients admitted to the Internal Medicine Department of the Vimercate Hospital were recruited between November 1, 2015 and October 31, 2016. All patients reporting an ADR associated with anticoagulant use were selected. Demographic, clinical, and observational data were extracted from electronic hospital records, in particular, by the hospital discharge letters and other clinical records. The main outcome of the study was to evaluate the incidence of anticoagulants serious adverse drug reactions conditioning hospital admission, the percentage of preventable reactions, and the determinants of those.

RESULTS AND DISCUSSION

Of the 2,064 admissions, 102 (4.9%) eligible patients were identified. Age ranged from 60-95 years (mean = 81.9, standard deviation = 6,59) and 47.1% (n=48) were female. Of the 102 cases, 68 used VKAs and 34 used DOACs. The most common admission diagnosis was heart failure following anemia or hemorrhage (56 cases), followed by acute hemorrhage (with or without anemia; 29 cases), and anemia not associated with evident hemorrhage (17cases). The majority of VKA users (n=65, 95.6%) had a high risk of major bleeding. ADRs were found to be preventable in 96% of VKA users and 68% of DOACs users.

CONCLUSION

This study highlights the large percentage of ADRs from oral anticoagulants that can be avoided with more careful patient management. Periodic check-up of cardiac and renal function, as well as blood count, may be useful for reducing the risk of ADRs, especially in older DOACs users. Further research is needed to get new data to improve the patients monitoring system.

Venous Thromboembolism in Special Populations: Preexisting Cardiopulmonary Disease, Cirrhosis, End-Stage Renal Disease, and Asplenia

Venous thromboembolism (VTE) is a common cause of morbidity and mortality. Presence of preexisting conditions, such as cardiopulmonary diseases, cirrhosis, renal dysfunction, and asplenia, commonly occurs in VTE patients. Moreover, these conditions often are risk factors for developing VTE. These preexisting conditions make VTE diagnosis and treatment challenging and worsen outcomes. Current guidelines do not include detailed features in the diagnosis and management of patients with preexisting conditions. This review discusses presence of VTE in patients with preexisting cardiopulmonary diseases, cirrhosis, renal dysfunction, and asplenia.

Pharmacokinetic drug interactions of the non-vitamin K antagonist oral anticoagulants (NOACs)

The use of warfarin, the most commonly prescribed oral anticoagulant, is being questioned by clinicians worldwide due to warfarin several limitations (a limited therapeutic window and significant variability in dose-response among individuals, in addition to a potential for drug-drug interactions). Therefore, the need for non-vitamin K antagonist oral anticoagulants (NOACs) with a rapid onset of antithrombotic effects and a predictable pharmacokinetic (PK) and pharmacodynamic (PD) profile led to the approval of five new drugs: the direct factor Xa (F-Xa) inhibitors rivaroxaban, apixaban, edoxaban and betrixaban (newly approved by FDA) and the direct thrombin (factor-IIa) inhibitor dabigatran etexilate. The advantages of NOACs over warfarin are a fixed-dosage, the absence of the need for drug monitoring for changes in anti-coagulation and fewer clinically significant PK and PD drug-drug interactions. NOACs exposure will likely be increased by the administration of strong P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4-inhibitors and may increase the risk of bleeds. On the contrary, P-gp inducers could significantly decrease the NOACs plasma concentration with an associated reduction in their anticoagulant effects. This manuscript gives an overview of NOACs PK profiles and their drug-drug interactions potential. This is meant to be of help to physicians in choosing the best therapeutic approach for their patients.

ESC position paper on cardiovascular toxicity of cancer treatments: challenges and expectations

The recent position paper of the European Society of Cardiology (ESC) on cardiovascular toxicity of cancer treatments has attracted considerable interest by healthcare professionals, since it is the first concrete help in the difficult task of monitoring and approaching cardiovascular side effects of anticancer treatments. The ESC expert opinion was not intended as a clinical practice guideline; however, it reports major cardiovascular complications grouped into nine categories, addressing current clinical strategies for prevention and mitigation. In this point of view, we discuss key challenges emerging from critical appraisal of the ESC position paper: (1) the wide spectrum of cardiovascular toxicities associated with oncological drugs, focusing on targeted agents, (2) managing strategies in patients with cardiac implantable devices, (3) the underappreciated (but emerging) immune-related cardiovascular toxicities of checkpoint inhibitors, which may also result in severe heart failure and fulminant myocarditis, (4) the evolving role of anticoagulation in oncology, and the evidence supporting (or not) the use of direct-acting oral anticoagulants in cancer-associated thrombosis.

Evolving cardiovascular uses of direct-acting oral anticoagulants: a paradigm shift on the horizon?

Direct-acting oral anticoagulants (DOACs), by virtue of pharmacological properties perceived as innovative, are changing the therapeutic scenario of patients requiring short- and long-term anticoagulation. The evidence gathered so far (from pre-approval pivotal trials to real-world post-marketing observational data) consistently confirms that DOACs are overall comparable to vitamin-K antagonists (VKAs) in terms of safety, efficacy, effectiveness and unequivocally documents a clinically relevant reduced risk of intracranial bleeding in the settings of non-valvular atrial fibrillation (AF) and venous thromboembolism. The following issues are attracting considerable clinical interest: (a) identifying specific subpopulations of patients with AF most likely to benefit from one of these agents (the so-called tailored therapy), and (b) expanding therapeutic indications in emerging diseases characterized by arterial and venous thromboembolic risk. In these scenarios, the risk-benefit profile of DOACs, as compared to VKAs or heparins, is still incompletely characterized. In cardiology, the challenging task of selecting a suitable or even the most appropriate DOAC for patients with AF and a particular phenotype prompted experts to provide suggestions based on careful review of subgroups of patients from pivotal RCTs. However, in the past few months, variegated multicenter trials have been published (RE-CIRCUIT, PIONEER-AF-PCI, GEMINI-ACS-1), with potential influence on clinical practice. Therefore, this review aims to update the latest evidence on the evolving therapeutic uses of DOACs in the cardiovascular area, addressing potential impact for clinicians.

Dosing considerations in the use of the direct oral anticoagulants in the antiphospholipid syndrome

WHAT IS KNOWN AND OBJECTIVES

At least four prospective trials have been initiated investigating the direct oral anticoagulants in the antiphospholipid syndrome. Preliminary reports have supported their use in patients with a history of venous thrombosis and a target INR of 2-3, but there have also been reports of failure of these agents in the antiphospholipid syndrome. The objective is to present a case report that illustrates there may be important dosing issues when considering the use of these agents in patients with the antiphospholipid syndrome.

CASE SUMMARY

A 50-year-old woman with the antiphospholipid syndrome, manifesting clinically with recurrent pyoderma gangrenosum-like leg ulcers, was treated with apixaban, resulting in improved ulcer healing. For insurance purposes, she was switched to rivaroxaban with worsening of the ulcers which again improved when apixaban was resumed.

WHAT IS NEW AND CONCLUSION

Despite a similar half-life, pharmacokinetics and pharmacodynamics, the manufacturer-recommended maintenance dosing of apixaban is twice daily and rivaroxaban once daily. We believe this difference in recommended dose accounts for the differential clinical response noted in the present case report and that twice daily dosing and a larger daily dose of these agents may be more efficacious in potent hypercoagulable disorders, such as the antiphospholipid syndrome.