Pharmacokinetics Of Rivaroxaban Research Articles

The Impact of Dexamethasone and Prednisone on Apixaban and Rivaroxaban Exposure in COVID-19 Patients: A Physiologically Based Pharmacokinetic Modeling Study.

Dexamethasone (DEX) is currently the treatment of choice for patients with oxygen-dependent COVID-19. It has been observed, primarily in vitro, that dexamethasone induces the expression of CYP3A and the ABCB1 gene, which encodes P-glycoprotein (P-gp). This has raised concerns about potential interactions between DEX and substrates of CYP3A and P-gp, such as direct oral anticoagulants (DOAC). Currently, there is limited robust evidence to support a clinically significant interaction between DEX and DOAC. Using physiologically based pharmacokinetic modeling (PBPK), we investigated the impact of DEX administered in the context of SARS-CoV-2 infection on the pharmacokinetics of apixaban (APX) and rivaroxaban (RVX). After validating the induction effect of the DEX compound on two CYP3A4 substrates using the limited available studies, we optimized the compound in a COVID-19 patient population, where significantly higher DEX plasma concentrations were observed compared to healthy volunteers. Our PBPK-based PK simulations showed a 20% decrease in the AUC of APX and RVX in a worst-case scenario and when DEX was administered at 6 mg PO for 10 days. This finding confirms the limited clinical data currently available and supports the use of APX and RVX with DEX in COVID-19 patients at low-risk for thrombo-embolism. In addition, our results suggest that prednisone (PRED), when used at an equipotent dose, could serve as a viable alternative to DEX, given its less pronounced induction effect on APX and RVX. Further research is needed to validate these findings and to explore the clinical implications of using PRED in place of DEX in such scenarios.

Rivaroxaban for Thromboembolism Prophylaxis in Patients with Nephrotic Syndrome: A Single-Arm, Prospective Study

Introduction: Thromboembolism is a recognized complication of nephrotic syndrome (NS). Evidence supporting the use of rivaroxaban to prevent NS-related thrombosis is limited and controversial. This study aimed to explore the impact of NS on rivaroxaban pharmacokinetics and to collect observational data on the efficacy and safety of rivaroxaban as primary thromboprophylaxis in patients with NS. Methods: This prospective study analyzed 141 patients with NS who received rivaroxaban (10 mg/day) for thromboprophylaxis. High-performance liquid chromatography-tandem mass spectrometry was used to measure the trough and peak plasma concentrations (Ctrough and Cmax) of rivaroxaban. The influence of clinical and genetic factors on these concentrations was examined using multivariate logistic regression. Results: The median Cmax and Ctrough were 68.5 ng/mL (interquartile range [IQR], 31.7–105.5 ng/mL) and 4.4 ng/mL (IQR, 1.2–11.9 ng/mL), respectively. The incidence of thromboembolic events (TEs) was 12.8%, while that of bleeding events was 14.2%, although all were classified as minor. Albumin level was the most significant factor affecting Cmax (ρ = 0.55; p < 0.001) and was also significantly associated with TEs (0.81; 0.71–0.91 per 1.0 g/dL increase; p = 0.001) and bleeding risks (1.11; 1.03–1.19 per 1.0 g/dL increase; p = 0.008). Single nucleotide polymorphisms in the ABCB1 gene significantly influenced Ctrough but were not associated with clinical outcomes. Conclusion: Hypoalbuminemia significantly affects the pharmacokinetics of rivaroxaban in NS patients. A dose-adjustment strategy based on rivaroxaban concentrations, accounting for variable albumin levels, may improve the safety and efficacy of thromboprophylaxis in this population.

Co-Administration of Amiodarone Increases Bleeding by Affecting Rivaroxaban Pharmacokinetics in Patients with Atrial Fibrillation.

This study aimed to investigate the impact of the drug-drug interaction between rivaroxaban and amiodarone on the clinical outcomes in patients with non-valvular atrial fibrillation (NVAF), focusing on pharmacokinetic and pharmacodynamic (PK/PD) aspects. A prospective study enrolling 174 patients with NVAF who were treated with rivaroxaban was conducted. The patients were divided into two groups based on postoperative antiarrhythmic and anticoagulation strategies: the rivaroxaban group (Control group) and the rivaroxaban plus amiodarone group (Riv/Amio group). The trough plasma concentrations (Ctrough) of rivaroxaban, activated partial thromboplastin time (APTT), prothrombin time (PT), and the clinical outcomes between the two groups were compared. Patients receiving 20 mg of rivaroxaban in the Riv/Amio group had a higher concentration of rivaroxaban Ctrough than those in the Control group (p = 0.009). Furthermore, in patients with moderate to severe renal impairment, rivaroxaban Ctrough was significantly increased in the Riv/Amio group. There was no significant difference in PT and APTT between the two groups. Regarding the clinical outcomes, the combination of rivaroxaban and amiodarone medication was associated with a higher incidence of bleeding events (p = 0.041; HR = 2.83, 95% CI 1.05-7.66) and clinically relevant non-major bleeding (p = 0.021; HR = 3.65, 95% CI 1.21-10.94). Finally, independent risk factors for bleeding in NAVF patients treated with rivaroxaban were identified as its combination with amiodarone (p = 0.044; OR = 2.871, 95% CI 1.028-8.023). The combination of rivaroxaban and amiodarone led to changes in rivaroxaban pharmacokinetics and an elevated risk of bleeding events. Therefore, physicians prescribing rivaroxaban medications should assess the potential bleeding risk associated with the concurrent use of amiodarone, particularly in patients with renal impairment.

Full-dose rivaroxaban in patients with a history of bariatric surgery: bridging the knowledge gap through a phase 1 study

BackgroundBariatric surgery (BS) induces significant changes in gastrointestinal anatomy, potentially influencing the pharmacokinetics of orally administered drugs such as rivaroxaban. ObjectivesThis phase 1 study aimed to assess the pharmacokinetics and safety of full-dose rivaroxaban in post-BS patients. MethodsThe ABSORB (Rivaroxaban Pharmacokinetics and Pharmacodynamics After Bariatric Surgery and in Morbid Obesity) study was a single-center, nonrandomized, multiple-dose, parallel-design bioequivalence trial. Adult patients with stable weight after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) were compared with subjects with class III obesity and healthy controls. Participants received 20 mg of rivaroxaban daily for 8 days. ResultsPost-BS patients exhibited altered rivaroxaban pharmacokinetics, suggesting reduced absorption. Mean area under the concentration-time curve from time 0 to 24 hours after the first dose (RYGB, 1806.8 ng.h/mL; SG, 1648.9 ng.h/mL) was lower compared with that in controls (1893.5 ng.h/mL). At steady state, the area under the concentration-time curve values remained lower in BS groups (RYGB, 2129.9 ng.h/mL; SG, 1946.4 ng.h/mL) than in controls (2224.8 ng.h/mL). The maximum concentration after the first dose was lower in post-RYGB subjects (214.9 ng/mL) than in controls (264.1 ng/mL). This difference was less pronounced at steady state (RYGB, 256.9 ng/mL vs controls, 288.8 ng/mL). Neither BS group met bioequivalence criteria compared with controls, whereas the group with class III obesity met bioequivalence criteria compared with controls at steady state. ConclusionRivaroxaban displayed minor pharmacokinetic variations in post-BS patients. Given reported interindividual variability in the general population, these variations are unlikely to be of clinical significance. Our findings support rivaroxaban use in BS patients, emphasizing the need for further research in this area.

Pharmacokinetics of single-dose rivaroxaban under fed state in obese vs. non-obese subjects: An open-label controlled clinical trial (RIVOBESE-PK).

The evidence of rivaroxaban's pharmacokinetics in obese compared with non-obese populations remains inconclusive. We aimed to compare the pharmacokinetic profile of rivaroxaban between obese and non-obese populations under fed state. Participants who met the study's eligibility criteria were assigned into one of two groups: obese (body mass index ≥35 kg/m2) or non-obese (body mass index 18.5-24.9 kg/m2). A single dose of rivaroxaban 20 mg was orally administered to each participant. Nine blood samples over 48 h, and multiple urine samples over 18 h were collected and analyzed for rivaroxaban concentration using ultra-performance liquid chromatography coupled with tandem mass detector. Pharmacokinetic parameters were determined using WinNonlin software. Thirty-six participants were recruited into the study. No significant changes were observed between obese and non-obese participants in peak plasma concentration, time to reach peak plasma concentration, area under the plasma concentration-time curve over 48 h or to infinity, elimination rate constant, half-life, apparent volume of distribution, apparent clearance, and fraction of drug excreted unchanged in urine over 18 h. Rivaroxaban's exposure was similar between the obese and non-obese subjects, and there were no significant differences in other pharmacokinetic parameters between the two groups. These results suggest that dose adjustment for rivaroxaban is probably unwarranted in the obese population.

ABCG2 polymorphism and rivaroxaban pharmacokinetics in healthy individuals after a single dose.

Rivaroxaban is a direct factor Xa inhibitor. Its interindividual variability is large and may be connected to the occurrence of adverse drug reactions or drug inefficacy. Pharmacogenetics studies concentrating on the reasons underlying rivaroxaban's inadequate response could help explain the differences in treatment results and medication safety profiles. Against this background, this study evaluated whether polymorphisms in the gene encoding the ABCG2 transporter modify the pharmacokinetic characteristics of rivaroxaban. A total of 117 healthy volunteers participated in two bioequivalence experiments with a single oral dose of 20 mg rivaroxaban, with one group fasting and the other being fed. Ultra-high-performance liquid chromatography coupled with mass spectrometry was employed to determine the plasma concentrations of rivaroxaban, and the WinNonlin program was used to calculate the pharmacokinetics parameters. In the fasting group, the rivaroxaban pharmacokinetic parameters of Vd (508.27 vs 334.45 vs 275.59 L) and t1/2 (41.04 vs 16.43 vs 15.47 h) were significantly higher in ABCG2 421 A/A genotype carriers than in ABCG2 421 C/C and 421 C/A genotype carriers (P<0.05). The mean values of Cmax (145.81 vs 176.27 vs 190.19 ng/mL), AUC0-t (1193.81 vs 1374.69 vs 1570.77 ng/mL·h), and Cl (11.82 vs 14.50 vs 13.01 mL/h) for these groups were lower, but this difference was not statistically significant (P>0.05). These findings suggested that the ABCG2 421 A/A genotype may impact rivaroxaban parameters after a single dose in healthy subjects. This finding must be validated before it is applied in clinical practice.

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 15mg, 10mg, or 5mg 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 20mg, 15mg, or 5mg 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.

Pharmacogenetics and pharmacokinetics of rivaroxaban in patients with atrial fibrillation and chronic kidney disease

Aim. To study the possible relationship between polymorphic variants of ABCB1 (rs2032582, rs1045642, rs1128503), CYP3A5 (rs776746), CYP3A4 (rs35599367) and CYP2J2 (rs890293) genes with residual equilibrium concentrations (Cmin,ss) of rivaroxaban in patients with non-valvular atrial fibrillation (AF) and stage 3 and 4 chronic kidney disease (CKD).Material and methods. A total of 123 patients 52 to 97 years old (median age, 82 years) with AF in combination with stage 3 and 4 CKD were included in the study. Each patient underwent a pharmacogenetic and pharmacokinetic study.Results. Cmin,ss and dose-adjusted concentration (Cmin,ss/D) of rivaroxaban were significantly higher in patients with the TT genotype than with the CT genotype of the polymorphic variant rs1045642 of the ABCB1 gene (Сmin,ss 60,5 [36,7;173] ng/ml and 54,8 [23,1;97,3] ng/ml, respectively, р=0,016; Сmin,ss/D 4,06[2,3;8,1] ng/ml/mg and 2,2 [1,1;4,9] ng/ml/mg, р=0,006). In patients with the T allele (CT and TT genotypes), compared with CC genotype carriers, Cmin,ss and Cmin,ss/D were significantly higher (Cmin,ss 60,5 [36,7;173] ng/ml and 45,8 [20,9;82,3] ng/ml, respectively, p=0,029; Cmin,ss/D 4,06 [2,3;8,1] ng/ml/ mg and 2,6 [1,2;4,8] ng/ml/mg, respectively, p=0,014). Also, Cmin,ss and Cmin,ss/D was significantly higher in patients with the TT genotype according to the polymorphic variant rs2032582 of the ABCB1 gene than in patients with the GG genotype (p=0,02 and р=0,016 respectively). Cmin,ss and Cmin,ss/D in T allele (GT and TT genotypes) carriers were significantly higher than in T allele homozygotes (Cmin,ss 57,1 [27,7;106,0] ng/ml versus 37,6 [18,6;61,7] ng/ml respectively, p=0,024; Cmin,ss/D 3,6 [1,7;7,4] ng/ml/mg versus 2,3 [1,1;4,09] ng/ml/mg respectively, p=0,032). Differences in Сmin,ss and Сmin,ss/D of rivaroxaban were detected when comparing TC, CC and TT genotypes of polymorphism rs1128503 of the ABCB1 gene. When comparing Сmin,ss and Сmin,ss/D of rivaroxaban among carriers of AG and GG genotypes of the rs776746 polymorphism of the CYP3A56986A&gt;G gene, no significance was detected (p&gt;0,05). Also, no difference in Cmin,ss and Cmin,ss/D was found when comparing carriers of the CC and CT genotypes of the rs35599367 polymorphism of the CYP3A4 gene, and carriers of the CC and AC genotypes of the rs890293 polymorphism of the CYP2J2 gene (p&gt;0,05).Conclusion. The carriage of T allele by polymorphic variants rs1045642 and rs2032582 of the ABCB1 gene affects Cmin,ss and Cmin,ss/D of rivaroxaban.

An eco-friendly ultra-performance liquid chromatography-mass spectrometry method for quantification of rivaroxaban and ticagrelor in rat plasma: grapefruit interactions.

Aim: An eco-friendly ultra-performance liquid chromatography-tandem mass spectrometry method was developed to study the pharmacokinetics of rivaroxaban and ticagrelor in rat plasma, utilizing moxifloxacin as an internal standard. The food-drug interaction between grapefruit juice and these drugs was also investigated. Methods: Liquid-liquid extraction was used. A nonporous stationary phase Agilent® Poroshell 120EC C18 column was used with methanol: 0.1% aqueous formic acid (95:5 v/v) as a mobile phase. The detection was performed in multiple reaction monitoring mode using positive electrospray ionization. The method's validation was conducted in accordance with US FDA and European Medicines Agency guidelines. Results & conclusion: Grapefruit juice should be ingested with caution in patients treated with antithrombotic medications as it may increase their plasma concentration, inducing bleeding, and requires close clinical monitoring.

Mutant CYP3A4/5 Correlated with Clinical Outcomes by Affecting Rivaroxaban Pharmacokinetics and Pharmacodynamics in Patients with Atrial Fibrillation.

This study was designed to investigate the impact of single-nucleotide polymorphism-encoded cytochrome P450 enzymes (CYP3A4/5) on clinical outcomes of rivaroxaban in patients with non-valvular atrial fibrillation (NVAF) based on pharmacokinetics and pharmacodynamics (PK/PD) aspects. A prospective study enrolling 165 rivaroxaban-treated patients with NVAF was conducted. Genotyping of CYP3A4 (rs2242480, rs2246709, rs3735451, and rs4646440) and CYP3A5 (rs776746) was performed to explore their impact on the trough plasma concentrations (Ctrough) of rivaroxaban, coagulation indicators at the Ctrough including activated partial thromboplastin time (APTT) and prothrombin time (PT), and clinical outcomes. Patients with mutant genotype CYP3A4 (rs2242480, rs2246709, and rs3735451) and CYP3A5 (rs776746) had higher levels of rivaroxaban Ctrough, PT values than that of wild-type. Furthermore, a positive relationship was revealed between Ctrough and PT (r = 0.212, p = 0.007), while no significant correlation was found between Ctrough and APTT. Regarding the clinical outcomes, the minor allele carriers on rs3735451 and the minor allele (A) carriers on rs2246709 were associated with higher incidence of minor bleeding (p = 0.028 and p = 0.038, respectively) and were identified as the independent risk factors of minor bleeding treated with rivaroxaban (p = 0.024 and p = 0.036, respectively), with the receiver operating characteristic (ROC) curve validated (AUC = 0.8956, 95% CI: 0.829-0.962). The CYP3A4 polymorphisms (rs2242480, rs2246709, and rs3735451) and CYP3A5 rs776746 were associated with variations in rivaroxaban PK/PD. The minor allele (C) carriers on rs3735451 and the minor allele (A) carriers on rs2246709 were correlated with clinical outcomes.

NAT2 phenotype alters pharmacokinetics of rivaroxaban in healthy volunteers

Rivaroxaban is a direct inhibitor of factor Xa, a member of direct oral anticoagulant group of drugs (DOACs). Despite being a widely extended alternative to vitamin K antagonists (i.e., acenocoumarol, warfarin) the interindividual variability of DOACs is significant, and may be related to adverse drug reaction occurrence or drug inefficacy, namely hemorrhagic or thromboembolic events. Since there is not a consistent analytic practice to monitor the anticoagulant activity of DOACs, previously reported polymorphisms in genes coding for proteins responsible for the activation, transport, or metabolism of DOACs were studied. The study population comprised 60 healthy volunteers, who completed two randomized, crossover bioequivalence clinical trials between two different rivaroxaban formulations. The effect of food, sex, biogeographical origin and 55 variants (8 phenotypes and 47 single nucleotide polymorphisms) in drug metabolizing enzyme genes (such as CYP2D6, CYP2C9, NAT2) and transporters (namely, ABCB1, ABCG2) on rivaroxaban pharmacokinetics was tested. Individuals dosed under fasting conditions presented lower tmax (2.21 h vs 2.88 h, β = 1.19, R2 =0.342, p = 0.012) compared to fed volunteers. NAT2 slow acetylators presented higher AUC∞ corrected by dose/weight (AUC∞/DW; 8243.90 vs 7698.20 and 7161.25 h*ng*mg /ml*kg, β = 0.154, R2 =0.250, p = 0.044), higher Cmax/DW (1070.99 vs 834.81 and 803.36 ng*mg /ml*kg, β = 0.245, R2 =0.320, p = 0.002), and lower tmax (2.63 vs 3.19 and 4.15 h, β = −0.346, R2 =0.282, p = 0.047) than NAT2 rapid and intermediate acetylators. No other association was statistically significant. Thus, slow NAT2 appear to have altered rivaroxaban pharmacokinetics, increasing AUC∞ and Cmax. Nonetheless, further research should be conducted to verify NAT2 involvement on rivaroxaban pharmacokinetics and to determine its clinical significance.

Pharmacogenetics of new oral anticoagulants

The review presents modern studies the effect of genetic polymorphisms on the efficienty and safety of therapy with new oral anticoagulants. Hepatic carboxylesterase encoded by the CES1 gene and P-glycoprotein encoded by the ABCB1 gene affect dabigatran pharmacokinetics. The role of glucuronidation enzymes (UGT2B15, UGT1A9, UGT2B7) involved in active dabigatran metabolism is poorly understood. An increase in the peak apixaban concentration was noted in patients with the rs4148738 polymorphism of the ABCB1 gene. Polymorphisms rs776746 and rs77674 of the CYP3A5 gene affect concentration of apixaban in Asian patients and thus increased the bleeding risk. The effect SULT1A1 sulfotransferase on the metabolism of apixaban has yet to be studied. The BCRP protein encoded by the ABCG2 gene is a poorly studied but promising direction for the pharmacokinetics of apixaban. ABCB1 and CYP3A4 of the cytochrome P450 system affect the rivaroxaban metabolism, however, the number of studies devoted to examining the effect of polymorphisms of these genes on the rivaroxaban pharmacokinetics limited. Thus, large studies are needed to clarify the clinical relevance of genotyping in target patients taking new oral anticoagulants.

Transferability of Published Population Pharmacokinetic Models for Apixaban and Rivaroxaban to Subjects with Obesity Treated for Venous Thromboembolism: A Systematic Review and External Evaluations.

Apixaban and rivaroxaban have first-line use for many patients needing anticoagulation for venous thromboembolism (VTE). The pharmacokinetics of these drugs in non-obese subjects have been extensively studied, and, while changes in pharmacokinetics have been documented in obese patients, data remain scarce for these anticoagulants. The aim of this study was to perform an external validation of published population pharmacokinetic (PPK) models of apixaban and rivaroxaban in a cohort of obese patients with VTE. A literature search was conducted in the PubMed/MEDLINE, Scopus, and Embase databases following the PRISMA statement. External validation was performed using MonolixSuite software, using prediction-based and simulation-based diagnostics. An external validation dataset from the university hospitals of Brest and Rennes, France, included 116 apixaban pharmacokinetic samples from 69 patients and 121 rivaroxaban samples from 81 patients. Five PPK models of apixaban and 16 models of rivaroxaban were included, according to the inclusion criteria of the study. Two of the apixaban PPK models presented acceptable performances, whereas no rivaroxaban PPK model did. This study identified two published models of apixaban applicable to apixaban in obese patients with VTE. However, none of the rivaroxaban models evaluated were applicable. Dedicated studies appear necessary to elucidate rivaroxaban pharmacokinetics in this population.

Is a Lower Dose of Rivaroxaban Required for Asians? A Systematic Review of a Population Pharmacokinetics and Pharmacodynamics Analysis of Rivaroxaban

Rivaroxaban has been widely used to prevent and treat various thromboembolic diseases for more than a decade. However, whether a lower dose of rivaroxaban is required for Asians is still debatable. This review aimed to explore the potential ethnic difference in pharmacokinetic/pharmacodynamic (PK/PD) characteristics between Asians and Caucasians. A systematic search was conducted and twenty-four studies were identified, of which 10 were conducted on Asian adults, 11 on predominantly Caucasian adults, and 3 on Caucasian pediatrics. The apparent clearance (CL/F) of rivaroxaban in Caucasian adults with non-valvular atrial fibrillation (6.45-7.64 L/h) was about 31-43% higher than that in Asians (4.46-5.98 L/h) taking 10~20 mg rivaroxaban every 24 h. Moreover, there was no obvious difference in CL/F among Japanese, Chinese, Thai, and Irani people. Regarding PK/PD relationship, prothrombin time was linked to rivaroxaban concentration in a linear or near-linear manner, and Factor Xa activity was linked with the Emax model. The exposure-response relationship was comparable between Asians and Caucasians. Renal function has a significant influence on CL/F, and no covariate was recognized for exposure-response relationship. In conclusion, a lower dose of rivaroxaban might be required for Asians, and further studies are warranted to verify this ethnic difference to facilitate optimal dosing regimens.

Effect of ABCB1 Gene Carriage and Drug-Drug Interactions on Apixaban and Rivaroxaban Pharmacokinetics and Clinical Outcomes in Patients with Atrial Fibrillation and Deep Vein Thrombosis

Aim. To investigate the effect of ABCB1 gene carriage and interdrug interactions on apixaban pharmacokinetics and clinical outcomes in patients with atrial fibrillation and deep vein thrombosis.Material and methods. Patients hospitalized at Yudin State Clinical Hospital participated in the study. A total of 92 patients (50 patients received apixaban and 42 – rivaroxaban) with non-valvular atrial fibrillation and deep vein thrombosis were included. Genotyping was performed by real-time polymerase chain reaction. Direct oral anticoagulants concentrations were measured using an electrospray ionization mass spectrometer in positive ionization mode.Results. In our study we found that in patients carrying the CT+TT ABCB1 (rs4148738) C&gt;T genotype encoding the carrier protein (P-gp), the plasma concentration of rivaroxaban was statistically significantly higher p= 0.026. In addition, we found that patients taking apixaban together with a CYP3A4/P-gp inhibitor were 3.5 times more likely to have hemorrhagic complications than those without inhibitors p = 0.004.Conclusion. Our study revealed that the plasma concentration of rivaroxaban was higher in patients carrying the ABCB1 (rs4148738) C&gt;T polymorphism T allele. And patients taking apixaban together with CYP3A4/P-gp inhibitor had higher risk of hemorrhagic complications in comparison with patients not taking such drugs. Further studies are needed on the influence of pharmacogenetics and pharmacokinetics on the safety and efficacy profile of apixaban and rivaroxaban, taking into account the trend of systemic approach to optimization of anticoagulant therapy of direct oral anticoagulants based on pharmacokinetic, pharmacogenetic biomarkers.

Abstract 12256: Symptomatic Supratherapeutic International Normalized Ratio on Rivaroxaban: A Case Report and a Systematic Review

Rivaroxaban is a direct oral anticoagulant that works by inhibiting factor Xa. Direct anticoagulants have largely replaced direct vitamin K inhibitors (VKAs) due to the increased risk of major hemorrhages and the need for regular monitoring and dose adjustments. However, there have been multiple reports of elevated international normalized ratio (INR) and incidents of bleeding in patients on rivaroxaban, which brings into question the potential need for monitoring. The purpose of this review is to differentiate the patients that may benefit from regular monitoring and to propose future directions for implementation of monitoring. Here we report a case of an INR of 4.8 in a patient who presented with a gastrointestinal bleed and a drop of five gm/dL in hemoglobin four days after starting rivaroxaban following right femoral popliteal bypass graft stenting. The patient had no liver or kidney abnormalities and was not taking any medication or consuming any foods that could introduce any significant drug interaction. Additionally, we conducted a systematic review of similar reports in the literature with the goal of identifying the factors that could influence rivaroxaban’s levels in the blood or its influence on the INR. We reviewed PubMed using keywords including; “rivaroxaban”, “anti-Xa”, “DOAC”, “elevated”, “INR”, “bleeding”, “hemorrhage”, “pharmacology”, and “pharmacokinetics”. The literature revealed reports of INRs up to 5.2. Reviewing the pharmacokinetics of rivaroxaban indicated possibly higher drug levels in Caucasians, patients with a low body mass index (BMI), and patients with polymorphisms in the genes coding for CYP3A4, CYP2J2, or p-glycoprotein, assuming no renal or liver disease and no significant drug-drug or drug-food interactions. INR can be falsely normal if the thromboplastin reagent used to monitor the INR on warfarin is not sensitive to the changes in INR due to rivaroxaban. We suggest finding a thromboplastin reagent that is sensitive to INR changes with rivaroxaban, which could yield clinically relevant INRs on rivaroxaban allowing for accurate monitoring. We then suggest conducting studies to evaluate the cost effectiveness of regular monitoring in at-risk patients.

Single-Dose Bioequivalence Study of Rivaroxaban-Containing Medicinal Products in Healthy Volunteers

Therapeutically, new oral anticoagulants (NOACs) are considered to be non-inferior or superior to vitamin K antagonists (warfarin). NOACs are included in current guidelines for the treatment of various cardiovascular diseases. Rivaroxaban medicinal products have been shown to effectively fight thrombotic complications of the new coronavirus infection, COVID-19. The wide clinical use of rivaroxaban products motivates the development of generics.The aim of the study was to compare the pharmacokinetics and safety of rivaroxaban medicinal products in a single-dose bioequivalence study in healthy volunteers under fasting conditions.Materials and methods: the bioequivalence study compared single-dose oral administration of Rivaroxaban, 10 mg film-coated tablets (NovaMedica Innotech LLC, Russia), and the reference product Xarelto®, 10 mg filmcoated tablets (Bayer AG, Germany), in healthy volunteers under fasting conditions. The open, randomised, crossover trial included 46 healthy volunteers. Each of the medicinal products (the test product and the reference product) was administered once; blood samples were collected during the 48 h after the administration. The washout between the study periods lasted 7 days. Rivaroxaban was quantified in plasma samples of the volunteers by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS).Results: no adverse events or serious adverse events were reported for the test and reference products during the study. The following pharmacokinetic parameters were obtained for Rivaroxaban and Xarelto®, respectively: Cmax of 134.6 ± 58.0 ng/mL and 139.9 ± 49.3 ng/mL, AUC0–48 of 949.7 ± 354.5 ng×h/mL and 967.6 ± 319.9 ng×h/mL, AUC 0–∞ of 986.9 ± 379.7 ng×h/mL and 1003.6 ± 320.4 ng×h/mL, T1/2 of 8.2 ± 3.2 h and 7.8 ± 3.3 h. The 90% confidence intervals for the ratios of Cmax, AUC0–48, and AUC0–∞ geometric means were 88.04–108.67%, 89.42–104.92% and 89.44–104.81%, respectively.Conclusions: the test product Rivaroxaban and the reference product Xarelto® were found to have similar rivaroxaban pharmacokinetics and safety profiles. The study demonstrated bioequivalence of the medicinal products.

Risk assessment and molecular mechanism study of drug-drug interactions between rivaroxaban and tyrosine kinase inhibitors mediated by CYP2J2/3A4 and BCRP/P-gp.

Cancer patients generally has a high risk of thrombotic diseases. However, anticoagulant therapy always aggravates bleeding risks. Rivaroxaban is one of the most widely used direct oral anticoagulants, which is used as anticoagulant treatment or prophylaxis in clinical practice. The present study aimed to systemically estimate the combination safety of rivaroxaban with tyrosine kinase inhibitors (TKIs) based on human cytochrome P450 (CYPs) and efflux transporters and to explore the drug–drug interaction (DDI) mechanisms in vivo and in vitro. In vivo pharmacokinetic experiments and in vitro enzyme incubation assays and bidirectional transport studies were conducted. Imatinib significantly increased the rivaroxaban Cmax value by 90.43% (p < 0.05) and the area under the curve value by 119.96% (p < 0.01) by inhibiting CYP2J2- and CYP3A4-mediated metabolism and breast cancer resistance protein (BCRP)- and P-glycoprotein (P-gp)-mediated efflux transportation in the absorption phase. In contrast, the combination of sunitinib with rivaroxaban reduced the exposure in vivo by 62.32% (p < 0.05) and the Cmax value by 72.56% (p < 0.05). In addition, gefitinib potently inhibited CYP2J2- and CYP3A4-mediated rivaroxaban metabolism with Ki values of 2.99 μΜ and 4.91 μΜ, respectively; however, it almost did not affect the pharmacokinetics of rivaroxaban in vivo. Taken together, clinically significant DDIs were observed in the combinations of rivaroxaban with imatinib and sunitinib. Imatinib increased the bleeding risks of rivaroxaban, while sunitinib had a risk of reducing therapy efficiency. Therefore, more attention should be paid to aviod harmful DDIs in the combinations of rivaroxaban with TKIs.

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

ABCB1 gene polymorphisms are associated with rivaroxaban distribution changes and adverse reactions but the data are controversial. Toevaluate the influence of ABCB1 (rs1045642 and rs4148738) gene polymorphisms on rivaroxaban pharmacokinetics in patients aged 80 years and older with nonvalvular atrial fibrillation (NAF). 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 (Cmin,ss) of rivaroxaban and prothrombin time (PT) and analyzed prior medical records for clinically relevant non-major bleeding (CRNMB). CC genotype carriers had no differences in Cmin,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). 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.

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

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. 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. 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 5.79L/h (relative standard error [RSE] 4.4%) and 51.5L (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 (Cmax,ss) and trough plasma concentration at steady state (Cmin,ss) were in the target range for different covariate levels. When patients were administered rivaroxaban 15 or 20mg once daily, the Cmax,ss and Cmin,ss in the different bodyweight levels were also in the target range. For patients with the ABCB1 rs4728709 mutation, the Cmin,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)]. 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.