Population Pharmacokinetics of Edoxaban in Japanese Atrial Fibrillation Patients With Severe Renal Impairment

Pharmacokinetics of Edoxaban 15 mg in Very Elderly Patients with Nonvalvular Atrial Fibrillation: A Subanalysis of the ELDERCARE-AF Study

BACKGROUND

 We evaluated the pharmacokinetics (PK) of low-dose (15 mg) edoxaban in very elderly patients (≥80 years) with nonvalvular atrial fibrillation (NVAF) and high bleeding risk.

METHODS

 This subanalysis of the phase 3, randomized, double-blind, placebo-controlled, multicenter ELDERCARE-AF study evaluated edoxaban plasma concentrations and compared them with the Japanese population of the ENGAGE AF-TIMI 48 and Japanese severe renal impairment (SRI) studies.

RESULTS

 The PK analysis population included 451 patients, 53.8% of whom concomitantly used antiplatelet drugs, 41.0% had SRI, and 38.0% had low body weight. Edoxaban plasma concentrations at trough and 1 to 3 hours post-dose in ELDERCARE-AF were 17.3 ± 13.9 (n = 427) and 93.3 ± 57.8 ng/mL (n = 447), respectively. These values were slightly higher than the 15 mg group in ENGAGE AF-TIMI 48 (n = 79; 12.4 ± 12.1 and n = 115; 78.7 ± 45.0 ng/mL, respectively), lower than the ENGAGE AF-TIMI 48 high-dose reduced to 30 mg group (n = 83; 25.1 ± 36.6 and n = 111; 150 ± 91.6 ng/mL, respectively), but similar to the Japanese SRI study (n = 39; 18.4 ± 11.2 and n = 40; 96.8 ± 48.3 ng/mL, respectively). ELDERCARE-AF patients with SRI and low body weight (≤45 kg) had higher concentrations than those without, and those taking antiplatelet drugs had lower concentrations than those who were not.

CONCLUSION

 PK data support edoxaban 15 mg once daily for very elderly NVAF patients with high bleeding risk, with caution for patients with SRI and/or low body weight.

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.

Insights into the Pharmacokinetics and Pharmacodynamics of Direct Oral Anticoagulants in Older Adults with Atrial Fibrillation: A Structured Narrative Review

Older adults, the fastest growing population, represent almost 50% of all users of direct oral anticoagulants (DOACs). Unfortunately, we have very little relevant pharmacological and clinical data on DOACs, especially in older adults with geriatric profiles. This is highly relevant as pharmacokinetics and pharmacodynamics (PK/PD) often differ substantially in this population. Hence, we need to obtain a better understanding of the PK/PD of DOACs in older adults, to ensure appropriate treatment. This review summarises the current insights into PK/PD of DOACs in older adults. A search was undertaken up to October 2022 to identify PK/PD studies of apixaban, dabigatran, edoxaban, and rivaroxaban, that included older adults aged ≥ 75 years. This review identified 44 articles. Older age alone did not influence exposure of edoxaban, rivaroxaban and dabigatran, while apixaban peak concentrations were 40% higher in older adults than in young volunteers. Nevertheless, high interindividual variability in DOAC exposure in older adults was noted, which can be explained by distinctive older patient characteristics, such as kidney function, changes in body composition (especially reduced muscle mass), and co-medication with P-gp inhibitors, which is in line with the current dosing reduction criteria of apixaban, edoxaban, and rivaroxaban. Dabigatran had the largest interindividual variability among all DOACs since its dose adjustment criterion is only age, and thus it is not a preferable option. Additionally, DOAC exposure, which fell outside of on-therapy ranges, was significantly related to stroke and bleeding events. No definite thresholds linked to these outcomes in older adults have been established.

Efficacy and safety of edoxaban tosylate hydrate 15 mg in the prevention of venous thromboembolism in patients with impaired renal function after orthopedic surgery of the lower extremities

Background

Although not indicated in the USA, edoxaban tosylate hydrate 15 mg is used for venous thromboembolism (VTE) prophylaxis after orthopedic surgery of the lower extremities in Japan. However, its efficacy and safety in patients with impaired renal function have not been fully evaluated. We aimed to investigate the intervention’s effectiveness in these patients.

Methods

From 2018 to 2020, patients who underwent total hip arthroplasty, total knee arthroplasty, hip fracture surgery, or knee arthroplasty single granule replacement and with renal dysfunction were evaluated. Safety was evaluated according to bleeding occurrence during edoxaban treatment and liver function endpoints. Patients were divided into the 15- and 30-mg oral groups, including 23 patients with impaired renal function and 209 with normal renal function, respectively.

Results

VTE incidence in the 15- and 30-mg groups was 8.7% and 8.6%, respectively; the intergroup difference was insignificant (odds ratio [OR] 0.99; 95% confidence interval [CI] 0.22–4.56; p = 1.00). Bleeding did not occur in the 15-mg group and was noted in 9 patients in the 30-mg group during treatment with edoxaban; the intergroup difference was insignificant (p = 1.00). The increase in aspartate aminotransferase and alanine aminotransferase levels was 30% in the 15-mg group and 19% in the 30-mg group, with no difference between the groups (p = 0.27). Multivariate analysis showed that the dose of edoxaban was not a significant factor associated with the incidence of VTE (adjusted OR 2.31; 95% CI 0.39–13.8; p = 0.36).

Conclusions

Edoxaban 15 mg in patients with impaired renal function may be as effective as edoxaban 30 mg in patients with normal renal function. However, the number of cases included in this study was small and the power was insufficient; therefore, a study with a larger sample size is desirable.

Responses of prothrombin time and activated partial thromboplastin time to edoxaban in Japanese patients with non-valvular atrial fibrillation: characteristics of representative reagents in Japan (CVI ARO 7)

The aims of this study were to determine the distribution of plasma concentration of edoxaban (PC-Ed) with their 90% interval (on therapy range) and its correlation with anticoagulation markers in patients with non-valvular atrial fibrillation (NVAF). Consecutive 97 NVAF patients under edoxaban therapy were evaluated (60/30 mg dose, n = 48/49; men/women, n = 71/26; age, 69 years). CHADS2 score 0, 1, and ≥ 2 were 27%, 44%, and 29%, respectively. The mean (90% interval) of PC-Ed by LC-MS/MS was 194.3 (49.4-345.3) and 17.0 (4.8-40.7) ng/mL at peak (2-4 h post-dose) and trough (pre-dose), respectively. Correlation of prothrombin time (PT) with PC-Ed was higher than that of activated partial thromboplastin time (aPTT). Among 6 PT reagents, Coagupia PT-N and Simplastin Excel S (both PT reagents) showed the highest predictive capability for the upper outlier of PC-Ed at peak and trough. Among 4 aPTT reagents, only Thrombocheck APTT measured at peak had a significant predictive capability. When using PT reagents, both peak and trough sampling showed a similar predictive capability for the upper outliers of PC-Ed with a high sensitivity, but a relatively low specificity. We demonstrated the distributions of plasma concentration, PT with 6 reagents, and aPTT with 4 reagents under edoxaban therapy in Japanese patients with NVAF, showing their 90% intervals. For predicting the upper outlier of PC-Ed, PT was more sensitive compared with aPTT, whereas predicting capability for the outliers of PC-Ed was mostly similar between peak and trough samplings among PT reagents (UMIN 000032492).

Effect of the number of dose adjustment factors on bleeding risk in patients receiving 30 mg/day edoxaban

What is known and objective

Edoxaban has three dose adjustment factors (creatinine clearance, 15‐50 mL/min; body weight, 60 kg or less; and concomitant medication with potent P‐glycoprotein inhibitors) to prevent bleeding that results from elevated blood concentrations of the drug. A dose reduction (from 60 to 30 mg/day of edoxaban) is recommended for patients with even one of those. However, it is not clear whether 30 mg/day of edoxaban is adequate for patients with multiple dose adjustment factors. We thus investigated the association between the number of the dose adjustment factors and bleeding risk in patients receiving edoxaban.

Methods

We retrospectively analysed 198 patients who received 30 mg/day of edoxaban between April 2015 and March 2017 with follow‐up for 1 year.

Results

The incidences of major bleeding were 1.4%, 7.3% and 20.0% in patients with 0‐1, 2 and 3 dose adjustment factors, respectively. The Cox proportional hazards regression model revealed that the risk of major bleeding was higher in patients with 2 (hazard ratio [HR]: 5.80, 95% confidence interval [CI]: 0.96‐44.05, P = .055) or 3 (HR: 17.70, 95% CI: 2.12‐147.70, P = .012) dose adjustment factors than in those with 0‐1 dose adjustment factor.

What is new and conclusion

This is the first study to evaluate the risk of bleeding in patients administered 30 mg/day of edoxaban based on the number of dose adjustment factors in clinical practice. For patients receiving edoxaban, as the number of the dose adjustment factors increases, the risk of major bleeding is elevated. In patients with multiple dose adjustment factors, not only one level of dose reduction, but further dose reductions may be considered. Further studies with a larger sample size are needed to confirm these findings.

Influence of Renal Function on the Pharmacokinetics, Pharmacodynamics, Efficacy, and Safety of Non-Vitamin K Antagonist Oral Anticoagulants

With the growing integration of non-vitamin K antagonist oral anticoagulants (NOACs) into clinical practice, questions have arisen regarding their use in special populations, including groups that may have been underrepresented in clinical trials. Patients with renal impairment, particularly in the lower echelons of renal function, are one such group. In an effort to elucidate the current evidence regarding the use of NOACs in patients with renal impairment, a systematic assessment of the literature was performed. The MEDLINE database was interrogated for studies and analyses evaluating the influence of renal function on the pharmacokinetics, pharmacodynamics, efficacy, and safety of NOACs published from January 1, 2000, through August 2, 2017. The 82 relevant publications retrieved highlight the diversity in the NOAC class regarding the impact of renal function on drug clearance, drug exposures, and clinical trial outcomes. In several large clinical trials, subgroup analyses revealed no significant differences when patients were stratified by creatinine clearance as a measure of renal function. Efficacy findings, in particular, were largely aligned with the overall population in the included studies. However, relative risks of bleeding were shown to vary, sometimes driven by changes in bleeding event rates in the comparator arm (eg, warfarin, enoxaparin). With few exceptions, minimal influence of mild renal impairment was observed on the relative efficacy and safety of NOACs. Taken together, the evidence suggests that the presence of renal impairment merits careful consideration of anticoagulant choice but should not deter physicians from appropriate use of NOACs.

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.

Integrated Population Pharmacokinetic Analysis of Rivaroxaban Across Multiple Patient Populations

The population pharmacokinetics (PK) of rivaroxaban have been evaluated in several population‐specific models. We developed an integrated population PK model using pooled data from 4,918 patients in 7 clinical trials across all approved indications. Effects of gender, age, and weight on apparent clearance (CL/F) and apparent volume of distribution (V/F), renal function, and comedication on CL/F, and relative bioavailability as a function of dose (F) were analyzed. Virtual subpopulations for exposure simulations were defined by age, creatinine clearance (CrCL) and body mass index (BMI). Rivaroxaban PK were adequately described by a one‐compartment disposition model with a first‐order absorption rate constant. Significant effects of CrCL, use of comedications, and study population on CL/F, age, weight, and gender on V/F, and dose on F were identified. CrCL had a modest influence on exposure, whereas age and BMI had a minor influence. The model was suitable to predict rivaroxaban exposure in patient subgroups of special interest.