Effects of renal impairment on the pharmacokinetics, pharmacodynamics and safety of rivaroxaban, an oral, direct Factor Xa inhibitor

Beyond Anticoagulation: A Comprehensive Review of Non-Vitamin K Oral Anticoagulants (NOACs) in Inflammation and Protease-Activated Receptor Signaling

Non-vitamin K oral anticoagulants (NOACs) have revolutionized anticoagulant therapy, offering improved safety and efficacy over traditional agents like warfarin. This review comprehensively examines the dual roles of NOACs-apixaban, rivaroxaban, edoxaban, and dabigatran-not only as anticoagulants, but also as modulators of inflammation via protease-activated receptor (PAR) signaling. We highlight the unique pharmacotherapeutic properties of each NOAC, supported by key clinical trials demonstrating their effectiveness in preventing thromboembolic events. Beyond their established anticoagulant roles, emerging research suggests that NOACs influence inflammation through PAR signaling pathways, implicating factors such as factor Xa (FXa) and thrombin in the modulation of inflammatory responses. This review synthesizes current evidence on the anti-inflammatory potential of NOACs, exploring their impact on inflammatory markers and conditions like atherosclerosis and diabetes. By delineating the mechanisms by which NOACs mediate anti-inflammatory effects, this work aims to expand their therapeutic utility, offering new perspectives for managing inflammatory diseases. Our findings underscore the broader clinical implications of NOACs, advocating for their consideration in therapeutic strategies aimed at addressing inflammation-related pathologies. This comprehensive synthesis not only enhances understanding of NOACs' multifaceted roles, but also paves the way for future research and clinical applications in inflammation and cardiovascular health.

Population pharmacokinetics of rivaroxaban in Chinese deep vein thrombosis patients and the exposure simulation for dosing recommendation

This study aimed to develop a population pharmacokinetic (PPK) model for rivaroxaban and establish a model-based dosing guideline tailored to Chinese patients with deep vein thrombosis (DVT). A nonlinear mixed-effects modeling approach was employed using Phoenix NLME 7.0 software to construct the PPK model for rivaroxaban. The PK of rivaroxaban was adequately characterized through a one-compartment model. Monte Carlo simulations were employed to formulate dosing guidelines applicable to different patient subgroups. Data from 60 Chinese DVT patients yielded 217 rivaroxaban plasma concentrations for analysis. The apparent clearance (CL/F) of rivaroxaban was found to be significantly influenced by the estimated glomerular filtration rate (eGFR), identified as a major covariate. Based on Monte Carlo simulations, for the acute DVT treatment, a regimen of 15 mg, 10 mg, or 5 mg twice daily was associated with the highest total probability target attainment (PTAtotal) in patients with normal, mildly impaired, or moderately impaired renal function, respectively. For the continued DVT treatment, a regimen of 20 mg, 15 mg, or 5 mg once daily exhibited the maximum PTAtotal in patients with normal, mildly impaired, or moderately impaired renal function, respectively. The recommendation label dose achieved the PK target in those with normal renal function. However, for patients with mild or moderate renal impairment, dose adjustments below the label recommendation might be necessary. The PPK model associated CL/F with the covariate eGFR. Utilizing the PPK model, a dosage regimen table was constructed to offer tailored dosing recommendations for Chinese DVT patients.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Efficacy and safety of anticoagulant for treatment and prophylaxis of VTE patients with renal insufficiency: a systemic review and meta-analysis

Patients with venous thromboembolism (VTE) comorbid renal insufficiency (RI) are at higher risk of bleeding and thrombosis. Recommendations in guidelines on anticoagulation therapy for those patients remain ambiguous. The goal of this study is to compare the efficacy and safety between different anticoagulant regimens in VTE patients comorbid RI at different stages of treatment and prophylaxis. We performed English-language searches of Pubmed, EMBASE, and Web of Science (inception to Nov 2022). RCTs evaluated anticoagulants for VTE treatment at the acute phase, extension phase, and prophylaxis in patients with RI and reported efficacy and safety outcomes were selected. The methodological quality of the studies was assessed at the outcome level using the risk-of-bias assessment tool developed by the Cochrane Bias Methods Group. A meta-analysis of twenty-five RCTs was conducted, comprising data from twenty-three articles, encompassing a total of 9,680 participants with RI. In the acute phase, the risk of bleeding was increased with novel oral anticoagulants (NOACs) compared to LMWH (RR 1.29, 95% CI 1.04-1.60). For the prophylaxis of VTE, NOACs were associated with an elevated risk of bleeding compared with placebo (RR 1.31, 95%CI 1.02-1.68). In comparison to non-RI patients, both NOACs and vitamin K antagonists (VKA) could increase the risk of bleeding among RI patients (RR 1.45, 95%CI 1.14-1.84 and RR 1.53, 95%CI 1.25-1.88, respectively) during acute phase, while NOACs may increase the incidence of VTE in RI population (RR 1.74, 95%CI 1.29-2.34). RI patients who are under routine anticoagulation have a significantly higher risk of adverse outcomes. LMWH is the most effective and safe option for VTE treatment or prophylaxis in patients with RI.

Nomogram for predicting bleeding events in nonvalvular atrial fibrillation patients receiving rivaroxaban: A retrospective study

Background and Aims

To construct a bleeding events prediction model of nonvalvular atrial fibrillation (NVAF) patients receiving rivaroxaban.

Methods

We conducted a retrospective cohort study in patients with NVAF who received rivaroxaban from June 2017 to March 2019. Demographic information and clinical characteristics were obtained from the electronic medical system. Univariate analysis was used to find the primary predictive factors of bleeding events in patients receiving rivaroxaban. Multiple analysis was conducted to screen the primary independent predictive factors selected from the univariate analysis. Finally, the independent influencing factors were applied to build a prediction model by using R software; then, a nomogram was established according to the selected variables visually, and the sensitivity and specificity of the model was evaluated.

Results

Twelve primary predictive factors were selected by univariate analysis from 46 variables, and multivariate analysis showed that older age, higher prothrombin time (PT) values, history of heart failure and stroke were independent risk factors of bleeding events. The area under curve (AUC) for this novel nomogram model was 0.828 (95% CI: 0.763-0.894). The mean AUC over 10-fold stratified cross-validation was 0.787, and subgroup analysis validation also showed a satisfied AUC. In addition, the decision curve analysis showed that the PT in combination with CHA2DS2-VASc and HASBLED was more practical and accurate for predicting bleeding events than using CHA2DS2-VASc and HASBLED alone.

Conclusions

PT in combination with CHA2DS2-VASc and HASBLED could be considered as a more practical and accurate method for predicting bleeding events in patients taking rivaroxaban.

Gene polymorphism as a cause of hemorrhagic complications in patients with non-valvular atrial fibrillation treated with oral vitamin K-independent anticoagulants

Atrial fibrillation (AF) accounts for 40% of all cardiac arrhythmias and is associated with a high risk of stroke and systemic thromboembolic complications. Dabigatran, rivaroxaban, apixaban, and edoxaban are direct oral anticoagulants (DOACs) that have been proven to prevent stroke in patients with non-valvular AF. This review summarizes the pharmacokinetics, pharmacodynamics, and drug interactions of DOACs, as well as new data from pharmacogenetic studies of these drugs. This review is aimed at analyzing the scientific literature on the gene polymorphisms involved in the metabolism of DOACs. We searched PubMed, Cochrane, Google Scholar, and CyberLeninka (Russian version) databases with keywords: 'dabigatran', 'apixaban', 'rivaroxaban', 'edoxaban', 'gene polymorphism', 'pharmacogenetics', 'ABCB1', 'CES1', 'SULT1A', 'ABCG2', and 'CYP3A4'. The articles referred for this review include (1) full-text articles; (2) study design with meta-analysis, an observational study in patients taking DOAC; and (3) data on the single-nucleotide polymorphisms and kinetic parameters of DOACs (plasma concentration), or a particular clinical outcome, published in English and Russian languages during the last 10 years. The ages of the patients ranged from 18 to 75 years. Out of 114 reviewed works, 24 were found eligible. As per the available pharmacogenomic data, polymorphisms affecting DOACs are different. This may aid in developing individual approaches to optimize DOAC pharmacotherapy to reduce the risk of hemorrhagic complications. However, large-scale population studies are required to determine the dosage of the new oral anticoagulants based on genotyping. Information on the genetic effects is limited owing to the lack of large-scale studies. Uncovering the mechanisms of the genetic basis of sensitivity to DOACs helps in developing personalized therapy based on patient-specific genetic variants and improves the efficacy and safety of DOACs in the general population.

Spontaneous hemothorax caused by rivaroxaban treatment for pulmonary embolism: A case report

Hemothorax is a rare and potentially fatal condition characterized by pleural effusion containing over 50% of the patient's hematocrit. A massive hemothorax involves blood loss exceeding 1.5 L. Common causes include chest trauma, invasive thoracic procedures, anticoagulant medications, vascular anomalies, malignancies, and hematologic abnormalities. Spontaneous hemothorax may be seen in conjunction with pulmonary infarction and spontaneous pneumothorax. Anticoagulation is a key therapeutic strategy for certain thromboembolic events, such as pulmonary embolism. Historically, these events were treated with vitamin K antagonists (VKAs), which have demonstrated variable plasma concentrations and an increased risk of hemorrhage. With the advent of direct oral anticoagulants (DOACs), treatment has become as effective as VKAs while significantly reducing the risk of hemorrhage. However, some researchers have speculated that hemorrhagic complications in certain cases could be worse with DOACs than with VKAs. In the case presented here, we identified a genuine association between the use of rivaroxaban and spontaneous hemothorax following the initiation of treatment for pulmonary embolism.

Platelet-rich fibrin ensures hemostasis after single-tooth removal under factor Xa inhibitors - a clinical prospective randomized split-mouth study

OBJECTIVES

In this prospective, double-blinded, randomized split-mouth study, the local hemostatic effect of platelet-rich fibrin (PRF) inserted into the extraction socket in patients taking factor Xa (FXa) inhibitors (apixaban, rivaroxaban, edoxaban) was compared to a hemostatic gelatine sponge (GS) as the "therapeutic gold standard" without withdrawal of oral anticoagulant therapy.

MATERIALS AND METHODS

Single-tooth extraction was conducted under local anesthesia in n = 21 patients using a split-mouth design (42 teeth). Using a double-blind approach, the extraction socket on one side of the jaw was filled with PRF and on the other with a GS. Bleeding was assessed immediately after surgery, in 30 min, 1 h, 1.5 h, and on follow-up appointments in 24 h and on the 7th day.

RESULTS

In 67% of cases, mild postoperative oozing could be stopped 30-90 min after tooth extraction via gauze pressure without any delayed bleeding. Concerning bleeding events, there was no difference among the PRF and GS groups and no significant difference among rivaroxaban, apixaban, and edoxaban (all p > 0.15).

CONCLUSION

PRF and GS are reliable hemostatic methods in postextraction sockets of patients taking FXa inhibitors.

CLINICAL RELEVANCE

Consequently, there is no need to discontinue FXa inhibitors because of a single-tooth removal, eliminating the risk of thrombus formation.

Pharmacokinetics and pharmacodynamics of direct oral anticoagulants

INTRODUCTION

Direct oral anticoagulants (DOACs) have overtaken vitamin K antagonists to become the most widely used method of anticoagulation for most indications. Their stable and predictable pharmacokinetics combined with relatively simple dosing, and the absence of routine monitoring has made them an attractive proposition for healthcare providers. Despite the benefits of DOACs as a class, important differences exist between individual DOAC drugs in respect of their pharmacokinetic and pharmacodynamic profiles with implications for dosing and reversal in cases of major bleeding.

AREAS COVERED

This review summarizes the state of knowledge relating to the pharmacokinetics of dabigatran (factor IIa/thrombin inhibitor) and apixaban, edoxaban and rivaroxaban (factor Xa) inhibitors. We focus on pharmacokinetic differences between the drugs which may have clinically significant implications.

EXPERT OPINION

Patient-centered care necessitates a careful consideration of the pharmacokinetic and pharmacodynamic differences between DOACs, and how these relate to individual patient circumstances. Prescribers should be aware of the potential for pharmacokinetic drug interactions with DOACs which may influence prescribing decisions in patients with multiple comorbidities. In order to give an appropriate dose of DOAC drugs, accurate estimation of renal function using the Cockcroft-Gault formula using actual body weight is necessary. An increasing body of evidence supports the use of DOACs in patients who are obese, and this is becoming more routine in clinical practice.

Construction of a risk scoring system using clinical factors and RYR2 polymorphisms for bleeding complications in patients on direct oral anticoagulants

Introduction: Bleeding is one of the most undesirable complications of direct oral anticoagulants (DOACs). While the ryanodine receptor (RYR2) has been related to cardiac diseases, research on bleeding complications is lacking. This study aimed to elucidate the association between RYR2 and bleeding risk to develop the risk scoring system in patients treated with DOACs. Methods: This study was a retrospective analysis of prospectively collected samples. We selected ten SNPs within the RYR2 gene, and two models were constructed (Model I: demographic factors only, Model II: demographic and genetic factors) in multivariable analysis. Independent risk factors for bleeding were used to develop a risk scoring system. Results: A total of 447 patients were included, and 49 experienced either major bleeding or clinically relevant non-major bleeding. In Model I, patients using rivaroxaban and experiencing anemia exhibited an increased bleeding risk after adjusting for covariates. Upon incorporating genetic factors into Model I, a significant association with bleeding was also observed in cases of overdosing on DOACs and in patients with a creatinine clearance (CrCl) < 30 mL/min, in addition to rivaroxaban and anemia (Model II). Among genetic factors, RYR2 rs12594 GG, rs17682073 AA, rs3766871 GG, and rs6678625 T alleles were associated with bleeding complications. The area under the receiver operating characteristic curve (AUROC) of Model I was 0.670, whereas that of Model II increased to 0.803, demonstrating better performance with the inclusion of genetic factors. Using the significant variables in Model II, a risk scoring system was constructed. The predicted bleeding risks for scores of 0, 1-2, 3-4, 5-6, 7-8, and 9-10 points were 0%, 1.2%, 4.6%, 15.7%, 41.7%, and 73.3%, respectively. Conclusion: This study revealed an association between RYR2 and bleeding complications among patients taking DOACs and established a risk scoring system to support individualized DOAC treatment for these patients.

Prescription of DOACs in Patients with Atrial Fibrillation at Different Stages of Renal Insufficiency

Atrial fibrillation (AF) and renal insufficiency often coexist and are increasingly prevalent with advancing age. Both the risk of thromboembolic events and bleeding propensity are higher in patients with AF and impaired renal function versus those with good renal health. Direct oral anticoagulants (DOACs) are being increasingly preferred over vitamin K antagonists (VKAs) in the treatment of patients with AF and impaired renal function as VKAs may accelerate progression of chronic kidney disease. DOACs, however, are eliminated by the kidneys to varying degrees, and their dosages must be adapted in accordance with renal function. Since creatinine clearance (CrCl) monitoring is recommended in patients with AF receiving DOAC therapy, CrCl must be routinely monitored in patients at the start and during the course of anticoagulation to avoid deviation from Summary of Product Characteristics dosage specifications. This review article provides an overview of current knowledge on the selection and dose of DOACs including apixaban, dabigatran, edoxaban and rivaroxaban in AF patients at different stages of renal insufficiency, with a special focus on elderly patients with comorbidities and receiving multiple medications. The groups discussed in this review include patients with varying levels of CrCl including hyperfiltration or CrCl > 90 ml/min, CrCl < 90-50 ml/min, CrCl < 50-30 ml/min, CrCl < 30-15 ml/min and end-stage renal disease or on dialysis.

Rivaroxaban-loaded SLNs with treatment potential of deep vein thrombosis: in-vitro, in-vivo, and toxicity evaluation

OBJECTIVES

Rivaroxaban (RXB), a novel Xa inhibitor having groundbreaking therapeutic potential. However, this drug is associated with few limitations, including its pharmacokinetics related toxicities. Here, we developed RXB-loaded SLNs (RXB-SLNs) to improve its biopharmaceutical profile. Methods: High pressure homogenizer was used to prepare RXB-SLNs, followed by their particle characterization, Transmission electron microscopy (TEM), Dynamic light scattering (DSC), and Powder X-ray diffraction (PXRD) analysis. Beside this, in-vitro, ex-vivo, and in-vivo evaluation, prothrombin time assessment and toxicity was investigated.

RESULTS

RXB-SLNs had their particle size in nano range (99.1 ± 5.50 nm) with excellent morphology and low polydispersity index (0.402 ± 0.02) and suitable zeta potential (-25.9 ± 1.4 mV). The incorporation efficiency was observed around 95.9 ± 3.9%. In-vitro release profiles of the RXB-SLNs exhibited enhanced dissolution (89 ± 9.91%) as compared to pure drug (11 ± 1.43%) after 24 h of the study. PK study demonstrated a seven times enhanced bioavailability of RXB-SLNs when compared with pure drug. Furthermore, RXB-SLNs exhibited an expressive anti-coagulant behavior in human and rat blood plasma. Also, the final formulation exhibited no toxicity after oral administration of the SLNs.

CONCLUSIONS

All together, these studies revealed the capability of the SLNs for carrying the RXB with enhanced therapeutic efficacy and no toxicity, most importantly for the treatment of deep vein thrombosis.

Oral factor Xa inhibitor underutilization following lower extremity peripheral vascular intervention

OBJECTIVE

Patients undergoing peripheral vascular intervention (PVI) (ie, endovascular revascularization) for symptomatic lower extremity peripheral artery disease remain at high risk for major adverse limb and cardiovascular events. High-quality evidence demonstrates the addition of a low-dose oral factor Xa inhibitor to single antiplatelet therapy, termed dual pathway inhibition (DPI), reduces the incidence of major adverse events in this population. This study aims to describe the longitudinal trends in factor Xa inhibitor initiation after PVI, identify patient and procedural characteristics associated with factor Xa inhibitor use, and describe temporal trends in antithrombic therapy post-PVI before vs after VOYAGER PAD.

METHODS

This retrospective cross-sectional study was performed using data from the Vascular Quality Initiative PVI registry from January 2018 through June 2022. Multivariate logistic regression was utilized to determine predictors of factor Xa inhibitor initiation following PVI, reported as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of 91,569 PVI procedures were deemed potentially eligible for factor Xa inhibitor initiation and were included in this analysis. Overall rates of factor Xa inhibitor initiation after PVI increased from 3.5% in 2018 to 9.1% in 2022 (P < .0001). The strongest positive predictors of factor Xa inhibitor initiation after PVI were non-elective (OR, 4.36; 95% CI, 4.06-4.68; P < .0001) or emergent (OR, 8.20; 95% CI, 7.14-9.41; P < .0001) status. The strongest negative predictor was postoperative dual antiplatelet therapy prescription (OR, 0.20; 95% CI, 0.17-0.23; P < .0001), highlighting significant hesitation about use of DPI after PVI and limited translation of VOYAGER PAD findings into clinical practice. Antiplatelet medications remain the most common antithrombotic regimen after PVI, with almost 70% of subjects discharged on dual antiplatelet therapy and approximately 20% discharged on single antiplatelet therapy.

CONCLUSIONS

Factor Xa inhibitor initiation after PVI has increased in recent years, although the absolute rate remains low, and most eligible patients are not prescribed this treatment.

The impact of ABCB1, CYP3A4/5 and ABCG2 gene polymorphisms on rivaroxaban trough concentrations and bleeding events in patients with non-valvular atrial fibrillation

BACKGROUND

The influence of genetic factors on the pharmacokinetics and clinical outcomes of rivaroxaban in patients with non-valvular atrial fibrillation (NVAF) is poorly understood. This study aimed to explore the effects of CYP3A4/5, ABCB1, and ABCG2 gene polymorphisms on the trough concentrations and the bleeding risk of rivaroxaban in NVAF patients.

PATIENTS AND METHODS

This study is a prospective multicenter study. The patient's blood samples were collected to detect the steady-state trough concentrations of rivaroxaban and gene polymorphisms. We visited the patients regularly at month 1, 3, 6, and 12 to record bleeding events and medications.

RESULTS

A total of 95 patients were enrolled in this study, and 9 gene loci were detected. For the dose-adjusted trough concentration ratio (C_trough/D) of rivaroxaban, the homozygous mutant type was significantly lower than wild type at ABCB1 rs4148738 locus (TT vs. CC, P = 0.033), and the mutant type was significantly lower than the wild type at ABCB1 rs4728709 locus (AA + GA vs. GG, P = 0.008). ABCB1 (rs1045642, rs1128503), CYP3A4 (rs2242480, rs4646437), CYP3A5 (rs776746), and ABCG2 (rs2231137, rs2231142) gene polymorphisms had no significant effect on the C_trough/D of rivaroxaban. For the bleeding events, we found that there were no significant differences among genotypes of all gene loci.

CONCLUSION

This study found for the first time that ABCB1 rs4148738 and rs4728709 gene polymorphisms had a significant impact on the C_trough/D of rivaroxaban in NVAF patients. CYP3A4/5, ABCB1, and ABCG2 gene polymorphisms were not associated with the bleeding risk of rivaroxaban.

First-in-human trial of SAR107375E, a novel small molecule anticoagulant with dual inhibition of factor Xa and factor IIa

BACKGROUND

SAR107375E is a direct dual inhibitor of both Factor Xa and Factor IIa and has shown potent anticoagulation activity in vitro and animals. This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of single ascending intravenous doses of SAR107375E in healthy Chinese adult subjects.

METHODS

In this randomized, double-blind, placebo-controlled trial, 60 healthy Chinese adult subjects were administered intravenously single ascending doses (0.5, 1.5, 3.0, 5.0, 7.5, 10.0, 15.0, or 20.0 mg) of SAR107375E (N = 44) or placebo (N = 16). Plasma and urine concentrations of SAR107375E were measured and used to calculate pharmacokinetic parameters. Coagulation functions were measured and compared with baseline values. Treatment-emergent adverse events were recorded to evaluate safety.

RESULTS

In plasma, from the 0.5 to 20.0 mg dose group, t1/2 is 1.51-4.00 h, Cmax is 59.05-1360 ug/L, and AUC0-t is 25.01-528.45 h*ug/L. And it shows dose proportionality in the 5.0-20.0 mg range. Activated partial thromboplastin time and Ecarin clotting time correlated linearly with drug plasma concentration. No serious adverse events were reported during the study.

CONCLUSION

SAR107375E exhibits good safety and tolerability, predictable pharmacokinetics and pharmacodynamics.

CLINICAL TRIAL REGISTRATION

www.chinadrugtrials.org.cn, identifier is CTR20211082.

Safety and Effectiveness of Rivaroxaban Versus Warfarin Across GFR Levels in Atrial Fibrillation: A Population-Based Study in Australia and Canada

Rationale & Objective

The benefit-risk profile of rivaroxaban versus warfarin for atrial fibrillation (AF) in patients with chronic kidney disease is uncertain. We compared rivaroxaban with warfarin across the range of kidney function in adults with AF.

Study Design

Multicenter retrospective cohort.

Setting & Participants

Adults with AF and a measure of estimated glomerular filtration rate (eGFR); using administrative data from 5 jurisdictions across Australia and Canada (2011-2018). Kidney function was categorized as eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m². Patients receiving dialysis and kidney transplant recipients were excluded.

Exposures

New dispensation of either rivaroxaban or warfarin.

Outcomes

Composite (1) effectiveness outcome (all-cause death, ischemic stroke, or transient ischemic attack) and (2) major bleeding events (intracranial, gastrointestinal, or other) at 1 year.

Analytical Approach

Cox proportional hazards models accounting for propensity score matching were performed independently in each jurisdiction and then pooled using random-effects meta-analysis.

Results

55,568 patients (27,784 rivaroxaban-warfarin user matched pairs; mean age 74 years, 46% female, 33.5% with eGFR <60 mL/min/1.73 m²) experienced a total of 4,733 (8.5%) effectiveness and 1,144 (2.0%) bleeding events. Compared to warfarin, rivaroxaban was associated with greater or similar effectiveness across a broad range of kidney function (pooled HRs of 0.72 [95% CI, 0.66-0.78], 0.78 [95% CI, 0.58-1.06], 0.70 [95% CI, 0.57-0.87], and 0.78 [95% CI, 0.62-0.99]) for eGFR ≥60, 45-59, 30-44, and <30 mL/min/1.73 m², respectively). Rivaroxaban was also associated with similar risk of major bleeding across all eGFR categories (pooled HRs of 0.75 [95% CI, 0.56-1.00], 1.01 [95% CI, 0.79-1.30], 0.87 [95% CI, 0.66-1.15], and 0.63 [95% CI, 0.37-1.09], respectively).

Limitations

Unmeasured treatment selection bias and residual confounding.

Conclusions

In adults with AF, rivaroxaban compared with warfarin was associated with lower or similar risk of all-cause death, ischemic stroke and transient ischemic attack and similar risk of bleeding across a broad range of kidney function.

Plain-Language Summary

This real-world study involved a large cohort of 55,568 adults with atrial fibrillation from 5 jurisdictions across Australia and Canada. It showed that the favorable safety (bleeding) and effectiveness (stroke or death) profile of rivaroxaban compared with warfarin was consistent across different levels of kidney function. This study adds important safety data on the use of rivaroxaban in patients with reduced kidney function, including those with estimated glomerular filtration rate <30 mL/min/1.73 m² in whom the risks and benefits of rivaroxaban use is most uncertain. Overall, the study supports the use of rivaroxaban as a safe and effective alternative to warfarin for atrial fibrillation across differing levels of kidney function.

Updated Renal Dosage Recommendations for Rivaroxaban in Patients Experiencing or at Risk of Thromboembolic Disease

Patients with chronic kidney disease are at an increased risk of venous thromboembolism (VTE). The factor Xa inhibitor rivaroxaban has been shown to provide similar efficacy and a lower risk of bleeding compared with vitamin K antagonists for the treatment and prevention of VTE. Rivaroxaban has been studied in patients with varying degrees of renal impairment, and this review summarizes current knowledge supporting its use in patients with severe renal impairment (creatinine clearance [CrCl] of 15 to < 30 mL/min) for the prevention, treatment, or prophylaxis of VTE. Clinical pharmacology studies have demonstrated an increase in rivaroxaban systemic exposure, factor Xa inhibition, and prothrombin time with decreasing renal function. These changes reach a plateau with comparable increases in exposure among individuals with moderate or severe renal impairment and end-stage renal disease. The clinical development program for the treatment and prevention of VTE as well as prophylaxis of deep vein thrombosis (DVT) following orthopedic surgery excluded patients with CrCl < 30 mL/min; however, a limited number of patients with severe renal impairment were enrolled. Efficacy outcomes in these patients with severe renal impairment were not meaningfully different from those of patients with higher levels of renal function. There was also no increase in the incidence of major bleeding with rivaroxaban in patients with CrCl < 30 mL/min. Taken together, these pharmacological and clinical data suggest that in patients with severe renal impairment, the approved dosages of rivaroxaban can be used in the treatment and prevention of VTE and for prophylaxis of DVT after hip or knee replacement surgery.

Study of Modifications Induced by Continued Direct Oral Anticoagulant Therapy during Atrial Fibrillation Ablation Procedures on Standard Hemostasis Parameters

Background: Unfractionated heparin (UFH) is used as an anticoagulant during the atrial fibrillation (AF) ablation procedure to prevent the occurrence of thromboembolic events. Guidelines recommend an activated clotting time (ACT) greater than 300 s (s) based on studies of patients treated with vitamin K antagonist (VKA) for their AF. However, direct oral anticoagulants (DOACs) have supplanted VKAs in AF and are now used as first-line therapy. It is recommended not to interrupt them during the procedure, which could interfere with the ACT measures. Objective: To assess the real-life relationship between ACT, DOAC concentrations, and UFH anti-Xa activity in patients treated by uninterrupted DOAC therapy. Methods: We conducted a single-center retrospective study. We analyzed consecutive patients with AF who underwent catheter ablation under DOAC therapy. Results: In total, 40 patients were included, including 15 (37.5%), 20 (50.0%), and 5 (12.5%) on rivaroxaban, apixaban, and dabigatran, respectively. Baseline ACT was significantly lower in the apixaban group. ACT was linearly correlated with the residual concentration of apixaban and dabigatran but not with rivaroxaban. After UFH injection, ACT was linearly correlated with the anti-Xa activity, regardless of DOAC. Patients in the apixaban group received a higher total dose of UFH during the procedure to achieve a target ACT > 300 s, which resulted in significantly higher anti-Xa activity during the procedure. Conclusion: Our results raise the question of optimal management of intra-procedural heparin therapy and highlight the limitations of the ACT test, particularly in patients on apixaban.

Application of rivaroxaban in patients with non-valvular atrial fibrillation and end-stage kidney disease: A systematic review and meta-analysis

Background

Nowadays, the number of patients with non-valvular atrial fibrillation (NVAF) complicated by end-stage renal disease (ESKD) is increasing. There are significant challenges in anticoagulation with prescription drugs because of the high risk of bleeding and embolism among these patients. However, no randomized controlled trials (RCTs) of warfarin in combination with any non-vitamin K oral anticoagulant (NOACs) have been performed in patients with baseline creatinine clearance (CrCl) <25 ml/min, which makes it difficult to justify the use of anticoagulants in such patients. Then, we aimed to collect and summarize all evidence to enable the anticoagulation of rivaroxaban, which is less cleared by the kidneys, in patients with severe renal insufficiency and to complement and improve the evidence on the use of rivaroxaban for anticoagulation.

Methods

The present systematic review and meta-analysis searched the databases of PubMed, Embase, the Cochrane Library, CNKI, CBM, and Google Scholar for relevant studies from inception to 1 June 2022, with the restriction of English and Chinese. Eligible cohort studies and RCTs that reported efficacy outcomes [composite of stroke and systemic embolism (SSE), ischemic stroke (ICS), and systemic embolization] or safety outcomes [major bleeding, intracranial hemorrhage (ICH), and gastrointestinal bleeding (GIB)] of rivaroxaban in NVAF patients with ESKD were enrolled. Two authors completed the data extraction and quality assessment work, respectively. The Cochrane Collaboration tool for assessing the risk of bias was used for RCTs, and the NEW-Castle Ottawa scale was used for study quality assessment for cohort studies. Dichotomous variables were calculated as risk factors with 95% confidence intervals (CIs), and meta-analysis was performed to probe the effect of research design, rivaroxaban dose, and controlled drug factors on outcomes.

Results

In total, three studies were included for meta-analysis, involving 6,071 NVAF patients with ESKD, and two studies were included for qualitative analysis. All included studies were at low risk of bias. A meta-analysis demonstrated that mix-dose rivaroxaban caused no statistical discrepancy in the occurrence of thrombotic and bleeding events when compared to the control group (embolism, LogOR: -0.64, 95% CI: -1.05 to -0.23, P:0.25; bleeding, LogOR: -0.33, 95% CI: -0.63 to -0.03, P:0.15), and low-dose rivaroxaban produced similar results (embolism, LogOR: -1.04, 95% CI: -2.15 to 0.07, P:0.61; bleeding, LogOR: -0.81, 95% CI: -1.19 to -0.44, P:0.93).

Conclusion

In this study, low-dose rivaroxaban (10 mg, once a day) may benefit more than warfarin in patients with NVAF and ESKD.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier CRD42022330973.

Effectiveness and safety of direct oral anticoagulants in patients with venous thromboembolism and creatinine clearance < 30 mL/min

The few studies that compared direct oral anticoagulants (DOAC) vs. warfarin in the setting of advanced renal insufficiency have focused on patients with atrial fibrillation. The purpose of this observational, matched, cohort study of patients was to assess the effectiveness and safety of DOAC vs. warfarin for the treatment of venous thromboembolism (VTE) among patients with a creatinine clearance (CrCl) < 30 mL/min. This observational, cohort study included patients with VTE and CrCl < 30 mL/min who were newly initiated on a DOAC or warfarin between January 1, 2016 and December 31, 2020. DOAC patients were matched up to 1:2 to warfarin patients. Primary outcome was a composite of recurrent VTE, clinically-relevant bleeding, ischemic stroke, and all-cause mortality. Adjusted conditional, multivariate Cox proportional hazards modeling was used to assess outcomes. 626 DOAC patients were matched to 1071 warfarin patients. DOAC patients had a higher mean age, higher mean baseline CrCl, and were less likely to have been receiving dialysis. There was no statistically significant difference in the composite outcome between groups (adjusted hazard ratio [aHR] 1.13, 95% confidence interval [CI] 0.87-1.47) or in the individual components of the composite (all HR 95% CI crossed 1.00). Identification of statistically non-significant rates of bleeding and thromboembolic outcomes suggest that the use of DOAC or warfarin is reasonable in patients with VTE and CrCl < 30 mL/min.

Negative effects of rivaroxaban observed in a patient with multiple common risks triggered by a bicycle accident

The negative effects of anticoagulants are well-known in patients with renal impairment, drug-drug interaction, lower physical conditions, and multiple comorbidities. We highlight that even in patients with controllable multiple risks for rivaroxaban use, add-on inevitable risks will lead to negative effects greater than those expected.

Population Pharmacokinetics and Hemorrhagic Risk Analysis of Rivaroxaban in Elderly Chinese Patients With Nonvalvular Atrial Fibrillation

Rivaroxaban is a popular direct factor Xa inhibitor used for anticoagulation therapy in patients with nonvalvular atrial fibrillation (NVAF). The aim of this study was to establish a population pharmacokinetic (PPK) model for rivaroxaban in elderly Chinese patients with nonvalvular atrial fibrillation, evaluate precision dosing regimens, and analyze hemorrhagic risk after rivaroxaban treatment. A 1-compartment population PK model with estimated glomerular filtration rate (eGFR), total bilirubin (TBIL), and ABCB1 rs1045642 as major covariates for apparent clearance was developed using the nonlinear mixed-effects model (NONMEM). A Monte Carlo simulation was performed to evaluate various dosing schemes and different levels of covariates for the target range of therapeutic drug-monitoring concentrations (C_max,ss and C_min,ss ). The exposure to rivaroxaban was simulated and assessed through hemorrhagic risk evaluation. The results showed that the average probability of target attainment (PTA) for optimal dosing regimens with different covariate levels for the targeted C_max,ss and C_min,ss were 29.35% to 31.3% and 64.91% to 65.8%, respectively. A dosage of 10 mg of rivaroxaban in elderly Chinese patients with normal renal and liver function was appropriate. The area under the concentration-time curve estimated over 24 hours with precision dosing at steady state (AUC_24,ss ) was statistically significantly associated with an increased risk of bleeding events (OR 1.0006, 95%CI 1.0003 to 1.001, P < .0001), and the bleeding risk increased by 1.82-fold for every 1000 μg*h/L increase in AUC_24,ss . A lower dose is recommended for elderly patients with renal impairment to avoid overexposure and bleeding events. The PPK model could inform individualized dosing for elderly Chinese patients with nonvalvular atrial fibrillation receiving rivaroxaban anticoagulation therapy.

The non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients with high-normal renal function - A systematic review

Non-vitamin K antagonist oral anticoagulants (NOACs) have revolutionized treatment of atrial fibrillation. Although benefits of anticoagulation therapy are clear, a minority of patients still experience treatment inefficacy or harm. All NOACs have varying degree of renal clearance, which may significantly affect plasma concentrations. Pivotal clinical trials have explored the effects of dose reduction in patients with chronic renal disease. None of these have, however, specifically addressed the need for a dose up-titration in patients with renal hyperfiltration, in whom lower drug plasma levels are to be expected. A signal for lower efficacy in this patient subset has recently emerged. We systematically assessed the peer-reviewed scientific literature on this topic, including a recently reported randomized pharmacokinetic study in renal hyperfiltrators also reporting on ischemic and bleeding events. We conclude that the reduction in NOAC plasma levels in AF patients with renal hyperfiltration is limited in extent and, does not translate into a clinically meaningful reduction in efficacy for NOACs as compared to vitamin K antagonists (VKAs) in such patients. At the current state of knowledge, NOAC current dosing should not be altered in patients with high-normal renal function.

Leveraging a Previously Published Population Pharmacokinetic Model to Predict Rivaroxaban Exposure in Real-World Patients

Population pharmacokinetic (PK)/pharmacodynamic models are commonly used to inform drug dosing; however, often real-world patients are not well represented in the clinical trial population. We sought to determine how well dosing recommended in the rivaroxaban drug label results in exposure for real-world patients within a reference area under the concentration-time curve (AUC) range. To accomplish this, we assessed the utility of a prior published rivaroxaban population PK model to predict exposure in real-world patients. We used the model to predict rivaroxaban exposure for 230 real-world patients using 3 methods: (1) using patient phenotype information only, (2) using individual post hoc estimates of clearance from the prior model based on single PK samples of rivaroxaban collected at steady state without refitting of the prior model, and (3) using individual post hoc estimates of clearance from the prior model based on PK samples of rivaroxaban collected at steady state after refitting of the prior model. We compared the results across 3 software packages (NONMEM, Phoenix NLME, and Monolix). We found that while the average patient-assigned dosing per the drug label will likely result in the AUC falling within the reference range, AUC for most individual patients will be outside the reference range. When comparing post hoc estimates, the average pairwise percentage differences were all <10% when comparing the software packages, but individual pairwise estimates varied as much as 50%. This study demonstrates the use of a prior published rivaroxaban population PK model to predict exposure in real-world patients.

Trough Concentration Deficiency of Rivaroxaban in Patients With Nonvalvular Atrial Fibrillation Leading to Thromboembolism Events

ABSTRACT

This retrospective study investigated factors influencing the steady-state trough concentrations (C trough ) of rivaroxaban in patients with nonvalvular atrial fibrillation (NVAF). We retrieved data from patients with NAVF who first started rivaroxaban anticoagulation at the Fujian Provincial Hospital from October 2017 to October 2020 through the electronic medical record system. Patients were followed for 1 year after the first dose of rivaroxaban, and the primary efficacy and safety end points were recorded. All follow-up visits were completed by October 2021. A C trough of <12 ng/mL was defined as C trough deficiency. Factors that influenced rivaroxaban C trough deficiency were investigated using multivariate binary logistic regression analysis. Kaplan-Meier survival curve analysis was used to determine differences between C trough deficiency and event-free survival. A total of 167 patients with NVAF were enrolled in the study, including 113 men and 54 women, with an average (± SD) age of 70.40 ± 12.46 years. High albumin levels were an independent protective factor against C trough deficiency (odds ratio, 0.932; P = 0.031). C trough deficiency was associated with the probability of freedom from thrombotic events ( P = 0.004); however, there were no significant differences in the probability of freedom from bleeding events ( P > 0.05). In conclusion, among the variables studied, a low albumin level was the main contributor to C trough deficiency. Rivaroxaban C trough deficiency also increased thrombotic events, but this was not associated with hemorrhagic events in Chinese patients with NVAF.

Population pharmacokinetic and pharmacodynamic analysis of rivaroxaban in Chinese patients with non-valvular atrial fibrillation

Rivaroxaban, a direct factor Xa inhibitor, is widely used for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). The aim of this study was to conduct a population pharmacokinetic-pharmacodynamic (PK-PD) analysis of rivaroxaban in Chinese patients with NVAF to assess ethnic differences and provide model-based precision dosing. A total of 256 rivaroxaban plasma concentrations and 244 prothrombin time (PT) measurements were obtained from 195 Chinese NVAF patients from a prospective clinical trial. The population PK-PD model was developed using nonlinear mixed effects modeling (NONMEM) software. The PK of rivaroxaban was adequately described using a one-compartment model with first-order adsorption and elimination. Estimated glomerular filtration rate (eGFR) was identified as a major covariate for apparent clearance. No single nucleotide polymorphism was identified as a significant covariate. PT exhibited a linear relationship with rivaroxaban concentration. Total bilirubin (TBIL) and eGFR were identified as significant covariates for baseline PT. According to the Monte Carlo simulation, 15 mg for Chinese patients with eGFR ≥50 mL/min and normal liver function yielded an exposure comparable to 20 mg for Caucasian patients. Patients with moderately impaired renal function may require a lower dose of rivaroxaban to avoid overexposure. Moreover, there was an approximate 26% increase in PT levels in patients with TBIL of 34 μmol/L and eGFR of 30 mL/min, which could increase the risk of major bleeding. The established population PK-PD model could inform individualized dosing for Chinese NVAF patients who are administered rivaroxaban.

The Influence of ABCB1 (rs1045642 and rs4148738) Gene Polymorphisms on Rivaroxaban Pharmacokinetics in Patients Aged 80 Years and Older with Nonvalvular Atrial Fibrillation

INTRODUCTION

ABCB1 gene polymorphisms are associated with rivaroxaban distribution changes and adverse reactions but the data are controversial.

AIM

To evaluate the influence of ABCB1 (rs1045642 and rs4148738) gene polymorphisms on rivaroxaban pharmacokinetics in patients aged 80 years and older with nonvalvular atrial fibrillation (NAF).

METHODS

128 patients aged 80 years and older (median [Me] age 87.5 [83.0-90.0] years) with NAF were included. We performed ABCB1 (rs1045642 and rs4148738) genotyping, measured the trough steady-state plasma concentration (C_min,ss) of rivaroxaban and prothrombin time (PT) and analyzed prior medical records for clinically relevant non-major bleeding (CRNMB).

RESULTS

CC genotype carriers had no differences in C_min,ss (p > 0.05) compared with the CT and TT rs1045642 and rs4148738 genotypes carriers. CC genotype carriers had no differences in PT (p > 0.05) compared with the CT rs1045642 and rs4148738 and TT rs4148738 genotypes carriers. In the TT genotype PT levels were higher than in the CC rs1045642 genotype: Me 14.2 [13.0-16.1] sec vs 13.3 [12.4-14.5] sec (p = 0.049). Incidence of CRNMB was higher in patients with the TT genotype compared with the CC rs1045642 (29.3% vs 4.5%, p = 0.021) and rs4148738 (39.3% vs 8.1%, p = 0.008) and the CT genotype rs4148738 (39.3% vs 14.3%, p = 0.002).

CONCLUSION

ABCB1 (rs1045642 and rs4148738) polymorphisms didn't influence rivaroxaban pharmacokinetics in patients aged 80 years and older with NAF. TT carriers developed CRNMB more frequently compared with the CC rs1045642 and the CC and CT rs4148738 genotypes. The haplotype TT-TT haplotype was associated with a higher frequency of CRNMB.

Plasma Rivaroxaban Level in Patients With Early Stages of Chronic Kidney Disease-Relationships With Renal Function and Clinical Events

Introduction Drug accumulation of rivaroxaban is a concern in patients with chronic kidney disease (CKD). Data regarding the plasma rivaroxaban levels in early CKD patients and its relationship with clinical events is lacking. Methods Early CKD patients (Stage 1-3) with atrial fibrillation who received rivaroxaban (15 or 20 mg daily) were recruited. Plasma rivaroxaban levels were measured at 2 hours (peak) and 24 hours (trough) after drug administration, and correlated with eGFR and clinically significant events during the follow-up period (1 January 2018 to 31 October 2021). Results Ninety-two patients were included (CKD stage 1 n=10, stage 2 n=53, stage 3 n=29). Plasma trough levels in patients with stage 3 CKD were significantly higher than those with stage 2 and 1 CKD (66.0±34.9 ng/ml vs. 35.7 ± 24.7 ng/ml vs. 34.7 ± 26.2 ng/ml, respectively, p=0.005), and showed inverse relationship with eGFR (r=0.391, p=0.001) in patients receiving 20 mg daily. The plasma trough rivaroxaban level correlated with PT and APTT (r = 0.650 and 0.44, respectively, p<0.001 for both). Plasma trough rivaroxaban level in those with bleeding were higher than those who did not (59.9 ± 35.6 ng/ml vs. 41.1 ± 29.2 ng/ml, p=0.011), and multivariate analysis suggested that plasma trough rivaroxaban level was associated with the rate of bleeding complications (OR: 1.020, 95% CI 1.002-1.038, p=0.028). Conclusion Plasma trough rivaroxaban levels correlated with renal function in early CKD patients, and its measurement may help dosage optimization in patients with renal impairment. Moreover, our data suggests that there may be an association between plasma trough rivaroxaban level and the rate of bleeding complication.

Effect of Chronic Kidney Disease on the Renal Secretion via Organic Anion Transporters 1/3: Implications for Physiologically-Based Pharmacokinetic Modeling and Dose Adjustment

There is growing evidence that active tubular secretory clearance (CL_s) may not decline proportionally with the glomerular filtration rate (GFR) in chronic kidney disease (CKD), leading to the overestimation of renal clearance (CL_r) when using solely GFR to approximate disease effect on renal elimination. The clinical pharmacokinetic data of 33 renally secreted OAT1/3 substrates were collated to investigate the impact of mild, moderate, and severe CKD on CL_r, tubular secretion and protein binding (f_u,p). The f_u,p of the collated substrates ranged from 0.0026 to 1.0 in healthy populations; observed CKD‐related increase in the f_u,p (up to 2.7‐fold) of 8 highly bound substrates (f_u,p ≤ 0.2) was accounted for in the analysis. Use of prediction equation based on disease‐related changes in albumin resulted in underprediction of the CKD‐related increase in f_u,p of highly bound substrates, highlighting the necessity to measure protein binding in severe CKD. The critical analysis of clinical data for 33 OAT1/3 probes established that decrease in OAT1/3 activity proportional to the changes in GFR was insufficient to recapitulate effects of severe CKD on unbound tubular secretion clearance. OAT1/3‐mediated CL_s was estimated to decline by an additional 50% relative to the GFR decline in severe CKD, whereas change in active secretion in mild and moderate CKD was proportional to GFR. Consideration of this additional 50% decline in OAT1/3‐mediated CL_s is recommended for physiologically‐based pharmacokinetic models and dose adjustment of OAT1/3 substrates in severe CKD, especially for substrates with high contribution of the active secretion to CL_r.

Rivaroxaban population pharmacokinetic and pharmacodynamic modeling in Iranian patients

WHAT IS KNOWN AND OBJECTIVE

Although predictable pharmacokinetic and pharmacodynamic of rivaroxaban allow fixed dosing regimens without routine coagulation monitoring, there is still the necessity to monitor and predict the effects of rivaroxaban in specific conditions and different populations. The current study was designed and conducted to analyze the rivaroxaban population pharmacokinetics in Iranian patients and establish a pharmacokinetic/pharmacodynamic model to predict the relationship between rivaroxaban concentration and its anticoagulant activity.

METHODS

A sequential nonlinear mixed effect pharmacokinetic/pharmacodynamic modeling method was used to establish the relation between rivaroxaban concentration and anti-factor Xa activity, prothrombin time, and activated partial thromboplastin time (aPTT) as pharmacodynamic biomarkers in a population of sixty-nine Iranian patients under treatment with oral rivaroxaban. Rivaroxaban plasma concentration was quantified by a validated high-performance liquid chromatography-tandem mass spectrometry.

RESULTS AND DISCUSSION

The typical population values (inter-individual variability%) of the oral volume of distribution and clearance for a one-compartment model were 61.2 L (21%) and 3.68 L·h^-1 (61%), respectively. Creatinine clearance and Child-Turcotte-Pugh score were found to affect the clearance. A direct link linear structural model best fitted the data for both prothrombin time and aPTT. The baseline estimates of aPTT and prothrombin time in the population were 35.0 (15%) and 12.6 (2%) seconds, respectively. The slope of the relationship between apTT, prothrombin time, and rivaroxaban concentration was 0.033 (28%) and 0.018 (54%) s·ml·ng^-1 , respectively. The selected model for anti-factor Xa activity consisted of a direct link inhibitory E_max model with Hill coefficient. The maximum level of inhibition (E_max ) was 4 IU·ml^-1 . The concentration of rivaroxaban producing 50% of the maximum inhibitory effect (EC₅₀ ) was 180 (24%) ng·ml^-1 , and Hill coefficient (γ) was 1.44 (108%). No covariates showed a statistically significant effect on PT and activated partial thromboplastin time prolonging properties and anti-factor Xa activity.

WHAT IS NEW AND CONCLUSION

Our results confirmed that pharmacokinetic/pharmacodynamic models similar to those of the other studies describe the relationship between the rivaroxaban concentration and its anticoagulant effect in Iranian patients. However, considerable differences were observed in the parameters of the pharmacodynamics-pharmacokinetic models with the results of other reports that can explain the unpredictable effects of rivaroxaban in some patients.

Population Pharmacokinetics of Rivaroxaban in Chinese Patients with Non-Valvular Atrial Fibrillation: A Prospective Multicenter Study

BACKGROUND AND OBJECTIVE

Rivaroxaban is a novel oral anticoagulant widely used for thromboprophylaxis in patients with non-valvular atrial fibrillation (NVAF). The present study aimed to develop a population pharmacokinetic (PPK) model for rivaroxaban in Chinese patients with NVAF.

METHODS

We performed a prospective multicenter study. The plasma concentration of rivaroxaban was directly detected by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and indirectly by rivaroxaban-calibrated chromogenic anti-Xa assay (STA^®). Gene polymorphisms were detected by MassARRAY single nucleotide polymorphism genotyping technology. Nonlinear mixed-effects modeling was used to develop the PPK model for rivaroxaban in patients with NVAF, and we simulated the steady-state rivaroxaban exposures under different dosing strategies in different covariate levels.

RESULTS

A total of 150 patients from five centers were recruited, including 263 plasma concentrations detected by HPLC-MS/MS, 2626 gene polymorphisms, and 131 plasma concentrations detected by anti-Xa assay. In our study, an oral one-compartment model was used to describe the pharmacokinetics of rivaroxaban in patients with NVAF. In the final model, the estimated apparent clearance (CL/F) and volume of distribution (V/F) were 5.79 L/h (relative standard error [RSE] 4.4%) and 51.5 L (RSE 5.0%), respectively. Covariates in the final model included creatinine clearance, total bilirubin, rs4728709, and body weight. The simulation results showed that in the 15 mg once-daily dosing regimen, in most instances the maximum plasma concentration at steady state (C_max,ss) and trough plasma concentration at steady state (C_min,ss) were in the target range for different covariate levels. When patients were administered rivaroxaban 15 or 20 mg once daily, the C_max,ss and C_min,ss in the different bodyweight levels were also in the target range. For patients with the ABCB1 rs4728709 mutation, the C_min,ss in the 10, 15, and 20 mg once-daily dosing regimens were lower than the target range. The anti-Xa assay was highly linearly correlated with the HPLC-MS/MS method [y = 1.014x - 2.4648 (R² = 0.97)].

CONCLUSIONS

Our study was the first multicenter PPK model for rivaroxaban in Chinese patients with NVAF (Alfalfa-RIVAAF-PPK). The study found that 15 mg once daily may be suitable as the principal rivaroxaban dose for Chinese patients with NVAF. For patients with the rs4728709 mutation, it may be necessary to examine insufficient anticoagulation. We found that the rivaroxaban-calibrated chromogenic anti-Xa assay and HPLC-MS/MS method were highly linearly correlated. Prospective studies with larger sample sizes and real-world studies are needed for further verification.

Evaluating pharmacokinetic drug-drug interactions of direct oral anticoagulants in patients with renal dysfunction

INTRODUCTION

Drug transporters, metabolic enzymes, and renal clearance play significant roles in the pharmacokinetics of direct oral anticoagulants (DOACs). Recommendations for DOAC drug-drug interactions (DDIs) by the product labeling are limited to selected CYP3A4 and P-glycoprotein inhibitors and lack considerations for concomitant renal dysfunction.

AREAS COVERED

This review focuses on: 1) current recommendations for the management of pharmacokinetic DOAC DDIs and the evidence used to support them; 2) alterations in DOAC exposure in the setting of concomitant DDIs and mild, moderate, and severe renal impairment; 3) clinical outcomes associated with this combination; and 4) expert recommendations for the management of pharmacokinetic DOAC DDIs. English-language, full-text articles on apixaban, dabigatran, rivaroxaban, and edoxaban with a publication date up to 30 September 2021 were retrieved from PubMed.

EXPERT OPINION

Given the lack of supporting clinical data, empiric dose adjustments based on pharmacokinetic data alone should be avoided. When a considerable increase in a DOAC exposure is anticipated, it may be advisable to use an alternative DOAC or anticoagulant from a different class. Future research on identification of DOAC therapeutic ranges and target patient populations is needed to inform clinical utility of DOAC level monitoring to guide the management of DDIs.

Renal Function Protection as an Important Component of a Comprehensive Approach to the Management of Patients with Atrial Fibrillation

The increase in the life expectancy of the population  is accompanied by an increase in the prevalence of diseases for which old and senile age are risk factors. Atrial fibrillation (AF) and chronic kidney disease (CKD) are two diseases that can coexist in a patient. The risk of ac thromboembolic and hemorrhagic events in this case increases due to the mutual aggravating influence of these diseases. In addition,  these patients have a high incidence of coronary  events, and cardiovascular complications are the main cause of death in patients with AF and CKD. Consequently, such patients require an integrated  approach  to treatment,  and their management is a complex  clinical task. The direct oral anticoagulant rivaroxaban has been most studied in a population  of comorbid  AF and CKD  patients and has proven a high efficacy and safety profile in these patients in randomized controlled trials. In addition,  rivaroxaban has shown  a significant  reduction in the risk of myocardial  infarction  in various patients,  as well as the possibility of preserving renal function to a greater extent compared  with warfarin therapy, and a possible positive effect on reducing  the risk of cognitive impairment.  A single dosing  regimen  can improve adherence  to treatment,  which is one of the key conditions  for achieving  the above effects. Thus, these factors make it possible to achieve comprehensive protection of comorbid  patients with AF and CKD.

Rivaroxaban Pharmacokinetics in Obese Subjects: A Systematic Review

INTRODUCTION

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality globally. The direct oral anticoagulants, including rivaroxaban, are relatively novel therapeutic options in the treatment and prevention of VTE. There is a conflicting and inconclusive evidence surrounding the pharmacokinetics (PK) of rivaroxaban in patients with VTE who are obese.

OBJECTIVES

We conducted a systematic review to provide an overview, and to synthesize the available evidence in the current literature pertaining to rivaroxaban PK in obese subjects who are healthy or diseased.

METHODS

The PubMed, Embase, ScienceDirect, Rayyan, and Cochrane Library databases were systematically searched from 1 May 2021 through 28 February 2022. Studies investigating rivaroxaban PK in adult obese subjects were included in the review. Pertinent data, including anthropometric parameters, rivaroxaban dosage regimen, PK parameters, PK model, and outcome measures were extracted. Reference values of rivaroxaban PK parameters in the general population were used for comparison purposes. The review protocol was registered in the PROSPERO database (CRD42020177770).

RESULTS

In the 11 studies included in this systematic review, over 7140 healthy or diseased subjects received rivaroxaban therapy, with varying clinical indications in the diseased population. The reported PK parameters of rivaroxaban in obese subjects compared with reference values in the general population were variable. The reported values of the volume of distribution (V_d) among obese subjects (73.4-82.8 L) fell within the range of values reported/calculated for the general population (59.4-104 L), assuming complete bioavailability. However, some of the reported values of clearance (CL) in obese subjects (7.86-16.8 L.h^-1) do not fall within the range of values reported/calculated for the general population (5.57-11.3 L.h^-1). The reported maximum plasma concentrations in obese subjects versus the general population following a 10 mg dose were 149 vs. 143-180 µg.L^-1, and following a 20 mg dose were 214-305 vs. 299-360 µg.L^-1, respectively. The area under the plasma concentration versus time curves (AUC) over different intervals in obese subjects versus the general population following a 10 mg dose were 1155 (AUC from time zero to infinity [AUC_∞]) vs. 1029 (AUC_∞) µg.h.L^-1; and 1204-2800 (AUC from time zero to 24 h [AUC₂₄]) vs. 3200 (AUC₂₄) µg.h.L^-1, respectively, following a 20 mg dose. The reported values of half-life and time to reach the maximum plasma concentration in obese subjects versus the general population were not consistent across studies.

CONCLUSION

Variable changes and inconsistencies in different rivaroxaban PK parameters were reported in obese subjects. Further well-designed studies are warranted to better characterize the PK and clinical outcomes of rivaroxaban in subjects with obesity.

Developing LC-MS/MS methods to quantify rivaroxabanin human plasma and urine: application to therapeuticdrug monitoring

Rivaroxaban is an oral anticoagulant directly inhibiting Factor Xa activity, which is widely used for prophylaxis of thromboembolic disorders and is required for therapeutic drug monitoring (TDM) during therapyfor individual dosage adjustment. Thisstudyaimed at developing a liquidchromatography/tandem mass spectrometry method that was suitable forrivaroxaban TDM in human plasma and urine and exploring the feasibility of urine drug monitoring in medical care. The 3-min run of LC-MS/MS methodswereestablishedby employingan Acquity UPLC BEH C₁₈ (2.1 mm × 50 mm, 1.7 μm) column using gradient elution of 10 mmol/L ammonium acetate containing 0.1% formic acid - 0.1% formic acid acetonitrile as mobile phase at a flow rate of 0.4 mL/min with the calibration range of 0.5 ng/mL-400 ng/mL and 10 ng/mL-10000 ng/mLfor human plasma and urine, respectively. Rivaroxaban wasdetected on a triple quadrupole tandem mass spectrometer with electrospray ionization source in positive ion mode. Themethods showed good linearity within the calibration range. Theprecision and accuracy, matrix effect, extraction recovery and stability inboth human matrices were all validatedand meet the international guideline requirements. These validated methods had been successfullyapplied to support TDMofan aged patient receiving rivaroxaban for therapy.

How lower doses of direct oral anticoagulants are interpreted in clinical practice: a national survey of the Italian Atherosclerosis, Thrombosis and Vascular Biology (ATVB) Study Group

AIM

To evaluate the current interpretation of the lower doses of direct oral anticoagulants (DOAC) dabigatran, apixaban, edoxaban and rivaroxaban in nonvalvular atrial fibrillation.

METHODS

A questionnaire of 14 statements to which the possible answers were fully agree/partially agree/partially disagree/fully disagree or yes/no was prepared within the board of the Italian Atherosclerosis, Thrombosis and Vascular Biology Study Group and forwarded to individual Italian physicians.

RESULTS

A total of 620 complete questionnaires were received from nearly all the Italian regions and physicians of various medical specialists, either enabled or not for the prescription of DOAC. A wide agreement was found as regards the pharmacological, as well as clinical consequences of the administration of the lower dose of factor-Xa inhibitors both in patients with and without clinical and/or laboratory criteria requiring dose reduction. Wide agreement was also found as regards the presence of moderate kidney insufficiency in selecting the dose of DOAC. Instead, more debated were issues regarding the proportionality between dabigatran dose and plasma concentration and selection of dabigatran dose, as well as the role of measuring drug plasma concentration and/or determine the anticoagulant activity of factor-Xa inhibitors when used at the lower dose.

CONCLUSION

The interpretation of the lower doses of DOAC in current Italian clinical practice appears largely correct and shared. Because of the persistence of some residual uncertainties, essentially regarding dabigatran, however, continuous educational effort still appears warranted.

Application of a PBPK Model of Rivaroxaban to Prospective Simulations of Drug-Drug-Disease Interactions with Protein Kinase Inhibitors in CA-VTE

BACKGROUND AND PURPOSE

Rivaroxaban is a viable anticoagulant for the management of cancer associated venous thromboembolism (CA-VTE). A previously verified physiologically-based pharmacokinetic (PBPK) model of rivaroxaban established how its multiple pathways of elimination via both CYP3A4/2J2-mediated hepatic metabolism and organic anion transporter 3 (OAT3)/P-glycoprotein-mediated renal secretion predisposes rivaroxaban to drug-drug-disease interactions (DDDIs) with clinically relevant protein kinase inhibitors (PKIs). We proposed the application of PBPK modelling to prospectively interrogate clinically significant DDIs between rivaroxaban and PKIs (erlotinib and nilotinib) for dose adjustments in CA-VTE.

EXPERIMENTAL APPROACH

The inhibitory potencies of the PKIs on CYP3A4/2J2-mediated metabolism of rivaroxaban were characterized. Using prototypical OAT3 inhibitor ketoconazole, in vitro OAT3 inhibition assays were optimized to ascertain the in vivo relevance of derived transport inhibitory constants (K_i ). Untested DDDIs between rivaroxaban and erlotinib or nilotinib were simulated.

KEY RESULTS

Mechanism-based inactivation (MBI) of CYP3A4-mediated rivaroxaban metabolism by both PKIs and MBI of CYP2J2 by erlotinib were established. The importance of substrate specificity and nonspecific binding to derive OAT3-inhibitory K_i values of ketoconazole and nilotinib for the accurate prediction of interactions was illustrated. When simulated rivaroxaban exposure variations with concomitant erlotinib and nilotinib therapy were evaluated using published dose-exposure equivalence metrics and bleeding risk analyses, dose reductions from 20 mg to 15 mg and 10 mg in normal and mild renal dysfunction, respectively, were warranted.

CONCLUSION AND IMPLICATIONS

We established a PBPK-DDDI model to prospectively evaluate clinically relevant interactions between rivaroxaban and PKIs for the safe and efficacious management of CA-VTE.

[Features of anticoagulant therapy of atrial fibrillation in combination with impaired renal function]

This review focuses on issues of anticoagulant therapy in patients with atrial fibrillation (AF) associated with chronic kidney disease (CKD). Such patients are at high risk of stroke whereas the choice of an anticoagulant is difficult. A wealth of information about a negative effect of warfarin on the kidney function has accumulated. A need for an alternative therapy to warfarin for patients with stage 3-4 CKD has become imminent. In this regard, rivaroxaban seems to be an appropriate replacement for warfarin in such patients. In randomized, controlled studies that evaluated the efficacy of direct oral anticoagulants in comparison with warfarin, the efficacy and safety profile of a "kidney" dose in moderate disorders of kidney function has been studied only for rivaroxaban. Moreover, both randomized, controlled studies and studies performed in the conditions of clinical practice, have demonstrated a more favorable effect of rivaroxaban on kidney function compared to warfarin. Patients with AF associated with CKD require a comprehensive protection, which, according to results of clinical studies, may be provided by rivaroxaban.

Direct Oral Anticoagulants for the Treatment of Venous Thromboembolism in Patients With Active Cancer

BACKGROUND/AIM

Although direct oral anti - coagulants (DOACs) are as safe and effective as conventional anticoagulants for treating venous thromboembolism (VTE), we have insufficient evidence justifying their use in patients with active cancer. We investigated the safety and effectiveness of DOACs in patients with active cancer.

PATIENTS AND METHODS

To investigate the safety and efficacy of DOACs, we retrospectively extracted 312 consecutive patients with active cancer who were prescribed edoxaban, rivaroxaban or apixaban for VTE.

RESULTS

The most common primary cancer sites were the lung, stomach, colon/rectum, hematology, ovary, and pancreas. Fifty patients (16%) discontinued DOACs due to clinically relevant bleeding; major bleeding events occurred in 18 patients (5.4%). Thrombosis reduced or resolved in 144 of 167 evaluable patients (86%). In particular, pulmonary embolism was reduced or resolved in 46 of 50 patients (92%).

CONCLUSION

Our findings revealed that DOACs for cancer-associated VTE are as safe and effective as conventional anticoagulation therapy.

Population pharmacokinetic analysis of rivaroxaban in children and comparison to prospective physiologically-based pharmacokinetic predictions

Rivaroxaban has been investigated in the EINSTEIN‐Jr program for the treatment of acute venous thromboembolism (VTE) in children aged 0 to 18 years and in the UNIVERSE program for thromboprophylaxis in children aged 2 to 8 years with congenital heart disease after Fontan‐procedure. Physiologically‐based pharmacokinetic (PBPK) and population pharmacokinetic (PopPK) modeling were used throughout the pediatric development of rivaroxaban according to the learn‐and‐confirm paradigm. The development strategy was to match pediatric drug exposures to adult exposure proven to be safe and efficacious. In this analysis, a refined pediatric PopPK model for rivaroxaban based on integrated EINSTEIN‐Jr data and interim PK data from part A of the UNIVERSE phase III study was developed and the influence of potential covariates and intrinsic factors on rivaroxaban exposure was assessed. The model adequately described the observed pediatric PK data. PK parameters and exposure metrics estimated by the PopPK model were compared to the predictions from a previously published pediatric PBPK model for rivaroxaban. Ninety‐one percent of the individual post hoc clearance estimates were found within the 5th to 95th percentile of the PBPK model predictions. In patients below 2 years of age, however, clearance was underpredicted by the PBPK model. The iterative and integrative use of PBPK and PopPK modeling and simulation played a major role in the establishment of the bodyweight‐adjusted rivaroxaban dosing regimen that was ultimately confirmed to be a safe and efficacious dosing regimen for children aged 0 to 18 years with acute VTE in the EINSTEIN‐Jr phase III study.

Andexanet Alfa Use for Small Bowel Obstruction Patient With History of Sugiura Procedure

This case report is about a 51-year-old active duty male with JAK2 mutation and medical history significant for prehepatic portal hypertension from portal vein thrombus on lifelong anticoagulation with rivaroxaban, an oral factor Xa inhibitor, presenting with closed-loop small bowel obstruction requiring emergent laparotomy. We present this surgical case as it required emergent reversal of the oral factor Xa inhibitor with andexanet alfa.

Direct Oral Anticoagulants for Venous Thromboembolism Prophylaxis Following Robot-assisted Radical Cystectomy: A Retrospective Feasibility Study at a Single Academic Medical Center

OBJECTIVES

To evaluate the use of direct oral anticoagulants following radical cystectomy for venous thromboembolism prophylaxis. We compared the experience of those who received venous thromboembolism prophylaxis following a robot-assisted radical cystectomy with either a direct oral anticoagulant or enoxaparin.

METHODS

Medical records of 66 patients who underwent robot-assisted radical cystectomy between July 2017 and May 2020 at a single academic institution were reviewed retrospectively. Patients received extended prophylaxis with either a direct oral anticoagulant or enoxaparin before or following surgical discharge. Venous thromboembolic events and complications resulting in emergency department visits and readmissions were reviewed over a 90-day postoperative period.

RESULTS

A total of 4 venous thromboembolic events within 90 days of surgery were observed. Among patients taking enoxaparin, 5% (2/37) developed a deep vein thrombosis and 3% (1/37) developed a pulmonary embolism. Among patients taking direct oral anticoagulants, 3% (1/29) developed a deep vein thrombosis. Zero patients in the enoxaparin group and 3% (1/29) of patients in the direct oral anticoagulant group experienced bleeding that required an emergency department visit.

CONCLUSION

Direct oral anticoagulants performed comparably to enoxaparin in this feasibility study following robot-assisted radical cystectomy in 66 patients. No significant differences in the number of venous thromboembolisms or bleeding complications were observed. These data encourage future studies and support the prospect of direct oral anticoagulants as a potentially suitable oral alternative to injectable low molecular weight heparins for venous thromboembolism prophylaxis following radical cystectomy.

Predictive Performance of Physiology-Based Pharmacokinetic Dose Estimates for Pediatric Trials: Evaluation With 10 Bayer Small-Molecule Compounds in Children

Development and guidance of dosing schemes in children have been supported by physiology-based pharmacokinetic (PBPK) modeling for many years. PBPK models are built on a generic basis, where compound- and system-specific parameters are separated and can be exchanged, allowing the translation of these models from adults to children by accounting for physiological differences. Owing to these features, PBPK modeling is a valuable approach to support clinical decision making for dosing in children. In this analysis, we evaluate pediatric PBPK models for 10 small-molecule compounds that were applied to support clinical decision processes at Bayer for their predictive power in different age groups. Ratios of PBPK-predicted to observed PK parameters for the evaluated drugs in different pediatric age groups were estimated. Predictive performance was analyzed on the basis of a 2-fold error range and the bioequivalence range (ie, 0.8 ≤ predicted/observed ≤ 1.25). For all 10 compounds, all predicted-to-observed PK ratios were within a 2-fold error range (n = 27), with two-thirds of the ratios within the bioequivalence range (n = 18). The findings demonstrate that the pharmacokinetics of these compounds was successfully and adequately predicted in different pediatric age groups. This illustrates the applicability of PBPK for guiding dosing schemes in the pediatric population.

Developing a physiologically based pharmacokinetic model of apixaban to predict scenarios of drug-drug interactions, renal impairment and paediatric populations

AIMS

To develop a physiologically based pharmacokinetic (PBPK) model for apixaban, an oral anticoagulant with a narrow therapeutic index, and to predict PK profiles and potential drug-drug interactions (DDIs) in patients with renal impairment and paediatrics.

METHODS

A whole-body apixaban PBPK model was developed and validated in SimCYP for healthy adults with or without interacting drugs. The model was extended to renal impairment and paediatrics. Observed PK data in adults were compared with predicted data. The effect of renal function, age and DDIs on apixaban PK was investigated.

RESULTS

The PBPK model successfully predicted the PK of apixaban alone and under the influence of interacting drugs. For patients with renal impairment, the PBPK model successfully predicted the fold change in each impairment group; inhibitory DDI and renal impairment had a synergistic effect on the increase of apixaban exposure (e.g., almost 3-fold increase of AUC in ketoconazole + severe renal impairment group). For infants younger than 1 year, the exposure of apixaban decreased with increased weight-normalized clearance. For newborn infants, AUC of apixaban was >2-fold higher than that in children older than 1 year. Meanwhile, the effect of DDI seems to be weakened while the effect of renal impairment might be enhanced in infants younger than 1 year.

CONCLUSION

Our study provides a reasonable approach to estimate the dose adjustment for the first use of apixaban in special populations with complex situations, which has the opportunity to make the clinical practice much safer.

Estimation of absolute oral bioavailability without performing an intravenous clinical study

The absolute oral bioavailability (BA) of drugs are yet to be determined, and intravenous pharmacokinetic studies are currently considered indispensable for determining the BA values of oral drugs. The aim of this study was to develop and validate a novel approach to estimating BA values without intravenous pharmacokinetic data. Based on the drug inclusion criteria, such as exhibiting a urinary recovery rate of (R_u) of ≥20% in a clinical study, 13 drugs were included in the present study, and pharmacokinetic data for them were collected from the literature. The fraction excreted unchanged into urine (f_e) was calculated for healthy subjects by dividing the R_u value by the total recovery rate. The contribution of renal excretion to total clearance from the systemic circulation (R_ren) was estimated by subjecting oral clearance and creatinine clearance to regression in subjects with normal and impaired renal function. BA was estimated as f_e/R_ren and compared with the observed BA (BA_obs). The predicted BA values for 9 drugs fell within ±20% of their BA_obs. The examined approach makes it possible to estimate BA values for drugs with mean renal excretion values in healthy subjects and oral clearance in subjects with various renal function, without intravenous pharmacokinetic data.