Pharmacogenomics of Novel Direct Oral Anticoagulants: Newly Identified Genes and Genetic Variants

Common P-glycoprotein (ABCB1) polymorphisms do not seem to be associated with the risk of rivaroxaban-related bleeding events: Preliminary data

Introduction

Considering conflicting previous reports, we aimed to evaluate whether the common ABCB1 polymorphisms (rs1128503, rs2032582, rs1045642, rs4148738) affected the risk of bleeding in rivaroxaban-treated patients.

Materials and methods

We report preliminary data from a larger nested case-control study. Consecutive adults started on rivaroxaban for any indication requiring > 6 months of treatment were followed-up to one year. Patients who experienced major or non-major clinically relevant bleeding during the initial 6 months were considered cases, whereas subjects free of bleeding over > 6 months were controls. The polymorphisms of interest (rs1128503, rs2032582, rs1045642, rs4148738) were in a strong linkage disequilibrium, hence patients were classified regarding the "load" of variant alleles: 0-2, 3-5 or 6-8. The three subsets were balanced regarding a range of demographic, comorbidity, comedication and genetic characteristics. A logistic model was fitted to probability of bleeding.

Results

There were 60 cases and 220 controls. Raw proportions of cases were similar across the subsets with increasing number of ABCB1 variant alleles (0-2, N = 85; 3-6, N = 133; 6-8, N = 62): 22.4%, 21.8%, and 19.4%, respectively. Fully adjusted probabilities of bleeding were also similar across the subsets: 22.9%, 27.5% and 17.7%, respectively. No trend was observed (linear, t = -0.63, df = 273, P = 0.529; quadratic, t = -1.10, df = 273, P = 0.272). Of the 15 identified haplotypes, the completely variant (c.1236T_c.2677T(A)_c.3435T_c.2482-2236A) (40.7%) and completely wild-type (C_G_C_G) (39.5%) haplotypes prevailed, and had a closely similar prevalence of cases: 21.1% vs. 23.1%, respectively.

Conclusions

The evaluated common ABCB1 polymorphisms do not seem to affect the risk of early bleeding in patients started on rivaroxaban.

Efficacy and safety of antithrombotic therapy for preventing and treating pediatric thromboembolic disease: a systematic review

This review used traditional and network meta-analyses (NMA) to conduct a comprehensive study of antithrombotic therapies in children with thromboembolic disease. We searched the PubMed, Embase, Cochrane Library, Web of Science and ClinicalTrials.gov databases from their inception to 26 February, 2023. And we finally included 16 randomized controlled trials. In the prevention of thromboembolic events (TEs), the use of anticoagulants had a low risk of TEs (relative risk (RR) 0.73, 95% CI 0.56 to 0.94) and a high risk of minor bleeding (RR 1.43, 95% CI 1.09 to 1.86) compared with no anticoagulants. In the treatment of TEs, direct oral anticoagulants (DOACs) were not inferior to standard anticoagulation in terms of efficacy and safety outcomes. In NMA, rivaroxaban and apixaban showed the lowest risk for TEs and major or clinically relevant nonmajor bleeding. According to the overall assessment of efficacy and safety, dabigatran may be the best choice for children with thromboembolic disease. The results of our study will provide references and suggestions for clinical drug selection.

Differences in quality of anticoagulation care delivery according to ethnoracial group in the United States: A scoping review

Anticoagulation therapy is standard for conditions like atrial fibrillation, venous thromboembolism, and valvular heart disease, yet it is unclear if there are ethnoracial disparities in its quality and delivery in the United States. For this scoping review, electronic databases were searched for publications between January 1, 2011 - March 30, 2022. Eligible studies included all study designs, any setting within the United States, patients prescribed anticoagulation for any indication, outcomes reported for ≥ 2 distinct ethnoracial groups. The following four research questions were explored: Do ethnoracial differences exist in 1) access to guideline-based anticoagulation therapy, 2) quality of anticoagulation therapy management, 3) clinical outcomes related to anticoagulation care, 4) humanistic/educational outcomes related to anticoagulation therapy. A total of 5374 studies were screened, 570 studies received full-text review, and 96 studies were analyzed. The largest mapped focus was patients' access to guideline-based anticoagulation therapy (88/96 articles, 91.7%). Seventy-eight articles made statistical outcomes comparisons among ethnoracial groups. Across all four research questions, 79 articles demonstrated favorable outcomes for White patients compared to non-White patients, 38 articles showed no difference between White and non-White groups, and 8 favored non-White groups (the total exceeds the 78 articles with statistical outcomes as many articles reported multiple outcomes). Disparities disadvantaging non-White patients were most pronounced in access to guideline-based anticoagulation therapy (43/66 articles analyzed) and quality of anticoagulation management (19/21 articles analyzed). Although treatment guidelines do not differentiate anticoagulant therapy by ethnoracial group, this scoping review found consistently favorable outcomes for White patients over non-White patients in the domains of access to anticoagulation therapy for guideline-based indications and quality of anticoagulation therapy management. No differences among groups were noted in clinical outcomes, and very few studies assessed humanistic or educational outcomes.

Efficacy and safety of dabigatran and rivaroxaban in atrial fibrillation patients with impaired liver function: a multicenter retrospective cohort study

BACKGROUND

The efficacy and safety of direct oral anticoagulants (DOACs) in atrial fibrillation (AF) patients with impaired liver function (ILF) have not been sufficiently studied. The aim of this study was to evaluate the efficacy and safety of DOACs for stroke prevention in patients with AF and ILF.

METHOD

This study was based on data from 15 centers in China, including 4,982 AF patients. The patients were divided into 2 subgroups based on their liver function status: patients with normal liver function (NLF)(n = 4213) and patients with ILF (n = 769). Logistic regression analysis was used to investigate the risk of total bleeding, major bleeding, thromboembolism, and all-cause deaths in AF patients with NLF and ILF after taking dabigatran or rivaroxaban, respectively.

RESULTS

Among AF patients treated with dabigatran or rivaroxaban, patients with ILF were associated with significantly higher major bleeding, compared with NLF patients (aOR: 4.797; 95% CI: 2.224-10.256; P < 0.001). In patients with NLF, dabigatran (n = 2011) had considerably lower risk of total bleeding than rivaroxaban (n = 2202) (aOR: 1.23; 95% CI: 1.002-1.513; P = 0.049). In patients with ILF, dabigatran (n = 321) significantly favored lower risks of major bleeding compared with rivaroxaban(n = 448) (aOR: 5.484; 95% CI: 1.508-35.269; P = 0.026).

CONCLUSION

After using dabigatran or rivaroxaban, patients with ILF had remarkably increased risk of major bleeding compared with patients with NLF. In AF patients with NLF, dabigatran had the distinct strength of significantly reduced risk of total bleeding compared with rivaroxaban. In patients with AF and ILF, dabigatran use was associated with lower risk for major bleeding compared with rivaroxaban.

The Effect of ABCB1 and CES1 Polymorphisms on Plasma Levels of Dabigatran and Risk of Hemorrhagic Complications in Ischemic Stroke Patients

BACKGROUND

Dabigatran directly inhibits thrombin and is used in primary and secondary stroke prevention in individuals with nonvalvular atrial fibrillation. The prodrug dabigatran etexilate is absorbed by enteral P-glycoprotein (ABCB1) and then activated by hepatic and intestinal carboxylesterases (CES1) to produce active metabolites. Variations in dabigatran metabolism because of genetics may affect concentration levels and clinical outcomes.

STUDY QUESTION

We conducted a study to assess how polymorphisms in the CES1 (rs2244613) and ABCB1 (rs4148738) genes affect the through plasma level (cmin) of dabigatran and its correlation to clinical outcomes.

STUDY DESIGN

Retrospective multicentric study of consecutive patients on dabigatran therapy. Examination of CES1 rs2244613 and ABCB1 rs4148738 polymorphisms, cmin 12 hours after administration, clinical follow-up (ischemic stroke, major or clinically relevant hemorrhage, myocardial infarction, other thromboembolism, and death).

MEASURES AND OUTCOMES

A total of 432 patients received treatment for an average of 19.78 months (SD of 20.165). The sex distribution of the patients was 56.5% male, and the average age was 67.56 years (SD of 14.7). The ABCB1 variant genotype was present in 67.8% of patients, whereas 37.5% carried the CES1 polymorphism.

RESULTS

Compared with wild-type patients, patients with the CES1 variant had significantly lower dabigatran plasma levels (with a mean difference of 16.986; 95% confidence interval, 5.794-28.178 ng/mL, P = 0.003). We also found a significant risk of major bleeding in patients carrying the ABCB1 rs4148738 allele (hazard ratio = 1.99, confidence interval 95% 1.10 to 3.59, P = 0.024).

CONCLUSIONS

The CES1 variant genotype rs2244613 is closely linked with reduced cmin of dabigatran. Carriers of the ABCB1 rs4148738 polymorphism exhibit a tendency toward higher plasma levels of dabigatran, which leads to a significantly increased risk of bleeding.

Toward Genetic Testing of Rivaroxaban? Insights from a Systematic Review on the Role of Genetic Polymorphism in Rivaroxaban Therapy

BACKGROUND

Investigations into the rivaroxaban response from the perspective of genetic variation have been relatively recent and wide in scope, whereas there is no consensus on the necessity of genetic testing of rivaroxaban. Thus, this systematic review aims to thoroughly evaluate the relationship between genetic polymorphisms and rivaroxaban outcomes.

METHODS

The PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Chinese databases were searched to 23 October 2022. We included cohort studies reporting the pharmacogenetic correlation of rivaroxaban. Outcomes measured included efficacy (all-cause mortality, thromboembolic events and coagulation-related tests), safety (major bleeding, clinically relevant non-major bleeding [CRNMB] and any hemorrhage), and pharmacokinetic outcomes. A narrative synthesis was performed to summarize findings from individual studies according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the reporting guideline for Synthesis Without Meta-Analysis.

RESULTS

A total of 12 studies published between 2019 and 2022 involving 1364 patients were included. Ten, one, and six studies focused on the ABCB1, ABCG2, and CYP gene polymorphisms, respectively. Pharmacokinetic outcomes accounted for the majority of the outcomes reported (n = 11), followed by efficacy (n = 5) [including prothrombin time (PT) or international normalized ratio (n = 3), platelet inhibition rate (PIR) or platelet reactivity units (PRUs; n = 1), thromboembolic events (n = 1)], and safety (n = 5) [including major bleeding (n = 2), CRNMB (n = 2), any hemorrhage (n = 1)]. For ABCB1 gene polymorphism, the relationship between PT and ABCB1 rs1045642 was inconsistent across studies, however there was no pharmacogenetic relationship with other efficacy outcomes. Safety associations were found in ABCB1 rs4148738 and major bleeding, ABCB1 rs4148738 and CRNMB, ABCB1 rs1045642 and CRNMB, and ABCB1 rs2032582 and hemorrhage. Pharmacokinetic results were inconsistent among studies. For ABCG2 gene polymorphism, no correlation was observed between ABCG2 rs2231142 and dose-adjusted trough concentration (Cmin/D). For CYP gene polymorphisms, PIR or PRUs have a relationship with CYP2C19 rs12248560, however bleeding or pharmacokinetic effects did not show similar results.

CONCLUSIONS

Currently available data are insufficient to confirm the relationship between clinical or pharmacokinetic outcomes of rivaroxaban and gene polymorphisms. Proactive strategies are advised as a priority in clinical practice rather than detection of SNP genotyping.

CLINICAL TRIALS REGISTRATION

PROSPERO registration number CRD42022347907.

Prothrombin Complex Concentrate vs Conservative Management in ICH Associated With Direct Oral Anticoagulants

Importance

Intracerebral hemorrhage (ICH) associated with direct oral anticoagulant (DOAC) use carries extremely high morbidity and mortality. The clinical effectiveness of hemostatic therapy is unclear.

Objective

To compare the clinical and radiological outcomes of DOAC-associated ICH treated with prothrombin complex concentrate (PCC) vs conservative management.

Design, Setting, and Participants

In this population-based, propensity score-weighted retrospective cohort study, patients who developed DOAC-associated ICH from January 1, 2016, to December 31, 2021, in Hong Kong were identified. The outcomes of patients who received 25 to 50 IU/kg PCC with those who received no hemostatic agents were compared. Data were analyzed from May 1, 2022, to June 30, 2023.

Main Outcomes and Measures

The primary outcome was modified Rankin scale of 0 to 3 or returning to baseline functional status at 3 months. Secondary outcomes were mortality at 90 days, in-hospital mortality, and hematoma expansion. Weighted logistic regression was performed to evaluate the association of PCC with study outcomes. In unweighted logistic regression models, factors associated with good neurological outcome and hematoma expansion in DOAC-associated ICH were identified.

Results

A total of 232 patients with DOAC-associated ICH, with a mean (SD) age of 77.2 (9.3) years and 101 (44%) female patients, were included. Among these, 116 (50%) received conservative treatment and 102 (44%) received PCC. Overall, 74 patients (31%) patients had good neurological recovery and 92 (39%) died within 90 days. Median (IQR) baseline hematoma volume was 21.7 mL (3.6-66.1 mL). Compared with conservative management, PCC was not associated with improved neurological recovery (adjusted odds ratio [aOR], 0.62; 95% CI, 0.33-1.16; P = .14), mortality at 90 days (aOR, 1.03; 95% CI, 0.70-1.53; P = .88), in-hospital mortality (aOR, 1.11; 95% CI, 0.69-1.79; P = .66), or reduced hematoma expansion (aOR, 0.94; 95% CI, 0.38-2.31; P = .90). Higher baseline hematoma volume, lower Glasgow coma scale, and intraventricular hemorrhage were associated with lower odds of good neurological outcome but not hematoma expansion.

Conclusions and Relevance

In this cohort study, Chinese patients with DOAC-associated ICH had large baseline hematoma volumes and high rates of mortality and functional disability. PCC treatment was not associated with improved functional outcome, hematoma expansion, or mortality. Further studies on novel hemostatic agents as well as neurosurgical and adjunctive medical therapies are needed to identify the best management algorithm for DOAC-associated ICH.

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.

Comparison of the Correlation Between Coagulation Indices and Rivaroxaban Concentrations

BACKGROUND

Rivaroxaban has predictable pharmacokinetics and pharmacodynamics. However, monitoring rivaroxaban concentrations should be provided for special patients with hepatic insufficiency, high bleeding risk, and high thrombotic risk.

OBJECTIVE

This study aimed to correlate chromogenic anti-Xa assay, prothrombin time (PT), activated partial thromboplastin time (APTT), thromboelastogram reaction time (TEG R-time), and rivaroxaban concentration measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) (MS-Riva).

METHODS

Peripheral venous blood was collected from recruited patients 30 minutes before and 2 to 4 hours after drug administration. High-performance liquid chromatography-tandem mass spectrometry and chromogenic anti-Xa assay measured rivaroxaban concentration. Different assays were compared by Pearson correlation coefficient and Bland-Altman analysis.

RESULTS

A total of 104 patients with 191 plasma were included in the study. Overall analysis shows that chromogenic anti-Xa assay, PT, APTT, and TEG R-time strongly correlated with MS-Riva (r = 0.986; r = 0.884; r = 0.741; r = 0.739; P < 0.001). Rivaroxaban peak concentration detected by HPLC-MS/MS (MS-peak) showed a very strong correlation with the chromogenic anti-Xa assay (r = 0.977, P < 0.001) and moderate correlation with PT, APTT, and TEG R-time (r = 0.670; r = 0.571; r = 0.481, P < 0.001). Rivaroxaban trough concentration detected by HPLC-MS/MS (MS-trough) correlated strongly with the chromogenic anti-Xa assay (r = 0.884, P < 0.001), weakly with APTT (r = 0.313; P = 0.043), and not significantly with PT and TEG R-time (P = 0.140; P = 0.341).

CONCLUSION AND RELEVANCE

High-performance liquid chromatography-tandem mass spectrometry/MS is the preferred choice for monitoring peak and tough concentrations, followed by anti-Xa, while PT is only suitable for peak concentrations. This study can help the clinicians to better adjust the medication regimen and reduce the risk of recurrence of thrombosis as well as the risk of bleeding.

Association of ABCB1 gene polymorphisms rs1128503, rs2032582, rs4148738 with anemia in patients receiving dabigatran after total knee arthroplasty

PURPOSE

Dabigatran is usually prescribed in recommended doses without monitoring of the blood coagulation for the prevention of venous thromboembolism after joint arthroplasty. ABCB1 is a key gene in the metabolism of dabigatran etexilate. Its allele variants are likely to play a pivotal role in the occurrence of hemorrhagic complications.

METHODS

The prospective study included 127 patients with primary knee osteoarthritis undergoing total knee arthroplasty. Patients with anemia and coagulation disorders, elevated transaminase and creatinine levels as well as already receiving anticoagulant and antiplatelet therapy were excluded from the study. The association of ABCB1 gene polymorphisms rs1128503, rs2032582, rs4148738 with anemia as the outcome of dabigatran therapy was evaluated by single-nucleotide polymorphism analysis with a real-time polymerase chain reaction assay and laboratory blood tests. The beta regression model was used to predict the effect of polymorphisms on the studied laboratory markers. The probability of the type 1 error (p) was less than 0.05 was considered statistically significant. BenjaminiHochberg was used to correct for significance levels in multiple hypothesis tests. All calculations were performed using Rprogramming language v3.6.3.

RESULTS

For all polymorphisms there was no association with the level of platelets, protein, creatinine, alanine transaminase, prothrombin, international normalized ratio, activated partial thromboplastin time and fibrinogen. Carriers of rs1128503 (TT) had a significant decrease of hematocrit (p = 0.001), red blood count and hemoglobin (p = 0.015) while receiving dabigatran therapy during the postoperative period compared to the CC, CT. Carriers of rs2032582 (TT) had a significant decrease of hematocrit (p = 0.001), red blood count and hemoglobin (p = 0.006) while receiving dabigatran therapy during the postoperative period compared to the GG, GT phenotypes. These differences were not observed in carriers of rs4148738.

CONCLUSION

It might be necessary to reconsider thromboprophylaxis with dabigatran in carriers of rs1128503 (TT) or rs2032582 (TT) polymorphisms in favor of other new oral anticoagulants. The long-term implication of these findings would be the reduction of bleeding complications after total joint arthroplasty.

Direct oral anticoagulant concentrations and adherence in stroke patients

No therapeutic ranges linking drug concentrations of apixaban and rivaroxaban to clinical outcomes have been defined. We investigated whether direct oral anticoagulant (DOAC) concentrations among patients admitted to hospital with symptoms of stroke differed between those later verified to suffer an ischaemic cerebrovascular event (stroke or transient ischaemic attack) and those having other diagnoses (control group). Serum concentrations in 102 patients on DOAC for atrial fibrillation (84%) and thromboembolic disease (16%) were measured within 24 h of the acute event, employing ultra-high performance liquid chromatography with tandem mass spectrometry. We converted all concentrations to standardized trough levels. DOAC concentrations were lower in the 64 patients with verified ischaemic cerebrovascular event than in the 30 controls, 255 ± 155 versus 329 ± 144 nmol/L (p = 0.029), despite no statistically significant difference in self-reported adherence and daily dosages. Calculated concentrations were 5.4-596 nmol/L (median = 229 nmol/L) in the ischaemic stroke group and 41-602 nmol/L (median = 316 nmol/L) in controls. CHA2 DS2 -VASc score was significantly higher in the ischaemic stroke group than in controls (4.9 ± 1.6 versus 4.1 ± 1.7; p = 0.007). These results may suggest that patients with high cerebrovascular risk might benefit from higher DOAC levels than those with a lower risk.

Comparing Efficacy and Safety Between Patients With Atrial Fibrillation Taking Direct Oral Anticoagulants or Warfarin After Direct Oral Anticoagulant Failure

BACKGROUND

An increased risk of recurrent stroke is noted in patients with atrial fibrillation despite direct oral anticoagulant (DOAC) use. We investigated the efficacy and safety of treatment with each of 4 different DOACs or warfarin after DOAC failure.

METHODS AND RESULTS

We retrospectively analyzed patients with atrial fibrillation with ischemic stroke despite DOAC treatment between January 2002 and December 2016. The different outcomes of patients with DOAC failure were compared, including recurrent ischemic stroke, major cardiovascular events, intracranial hemorrhage and subarachnoid hemorrhage, mortality, and net composite outcomes according to switching to different DOACs or vitamin K antagonist after index ischemic stroke. We identified 3759 patients with DOAC failure. A total of 84 patients experienced recurrent ischemic stroke after switching to different oral anticoagulants, with a total follow-up time of 14 years. Using the vitamin K antagonist group as a reference, switching to any of the 4 DOACs was associated with a 69% to 77% reduced risk of major cardiovascular events (adjusted hazard ratio [aHR], 0.25 [95% CI, 0.16-0.39] for apixaban, 0.23 [95% CI, 0.14-0.37] for dabigatran, 0.23 [95% CI, 0.09-0.60] for edoxaban, and 0.31 [95% CI, 0.21-0.45] for rivaroxaban), and a 69% to 83% reduced risk of net composite outcomes (aHR, 0.25 [95% CI, 0.18-0.35] for apixaban, 0.17 [95% CI, 0.11-0.25] for dabigatran, 0.31 [95% CI, 0.17-0.56] for edoxaban, and 0.31 [95% CI, 0.23-0.41] for rivaroxaban).

CONCLUSIONS

In Asian patients with DOAC failure, continuing DOACs after index stroke was associated with fewer undesirable outcomes than switching to a vitamin K antagonist. Alternative pharmacologic and nonpharmacologic strategies warrant investigation.

Pharmacogenomics of Cardiovascular Drugs for Atherothrombotic, Thromboembolic and Atherosclerotic Risk

PURPOSE OF REVIEW

Advances in pharmacogenomics have paved the way for personalized medicine. Cardiovascular diseases still represent the leading cause of mortality in the world. The aim of this review is to summarize the background, rationale, and evidence of pharmacogenomics in cardiovascular medicine, in particular, the use of antiplatelet drugs, anticoagulants, and drugs used for the treatment of dyslipidemia.

RECENT FINDINGS

Randomized clinical trials have supported the role of a genotype-guided approach for antiplatelet therapy in patients with coronary heart disease undergoing percutaneous coronary interventions. Numerous studies demonstrate how the risk of ineffectiveness of new oral anticoagulants and vitamin K anticoagulants is linked to various genetic polymorphisms. Furthermore, there is growing evidence to support the association of some genetic variants and poor adherence to statin therapy, for example, due to the appearance of muscular symptoms. There is evidence for resistance to some drugs for the treatment of dyslipidemia, such as anti-PCSK9.

SUMMARY

Pharmacogenomics has the potential to improve patient care by providing the right drug to the right patient and could guide the identification of new drug therapies for cardiovascular disease. This is very important in cardiovascular diseases, which have high morbidity and mortality. The improvement in therapy could be reflected in the reduction of healthcare costs and patient mortality.

Comparison of the efficacy and safety between rivaroxaban and dabigatran in the treatment of acute portal vein thrombosis in cirrhosis

BACKGROUND

New oral anticoagulants (NOACs) have been becoming prevalent in recent years and are increasingly used in the treatment of port vein thrombosis. The difference of the efficacy and safety between rivaroxaban and dabigatran remains unclear in the treatment of cirrhotic patients with acute portal vein thrombosis (PVT).

METHODS

This retrospective study included all consecutive cirrhotic patients with acute portal vein thrombosis in our institute from January 2020 to December 2021. The patients received oral anticoagulation with rivaroxaban or dabigatran. The demographic, clinical, and imaging data of patients were collected. The diagnosis of acute PVT was confirmed by imaging examinations. The severity of liver cirrhosis was assessed using Child-Pugh score and Model for End-Stage Liver Disease (MELD) score. Outcomes included recanalization (complete, partial, and persistent occlusion), liver function, bleedings, and survival. The log-rank test was used to compare Kaplan-Meier distributions of time-to-event outcomes. The Cox proportional hazards model was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

A total of 94 patients were included, 52 patients (55%) received rivaroxaban and 42 (45%) with dabigatran. The complete and partial recanalization of PVT was observed in 41 patients. There was no significant difference in complete recanalization, partial recanalization, and persistent occlusion between the two groups. With multivariate analysis, D-dimer (HR 1.165, 95% CI 1.036-1.311, p = 0.011) was independent predictors of complete recanalization. The Child-Pugh score (p = 0.001) was significantly improved in both two groups after anticoagulation, respectively. However, there was no difference between the two groups. The probability of survival was 94%, 95% in the rivaroxaban and dabigatran groups (log-rank p = 0.830). Major bleedings were reported in 3 patients (6%) in rivaroxaban group and 1 patient (2%) in dabigatran group (p = 0.646). Six patients (12%) in rivaroxaban group experienced minor bleeding, and five (12%) from dabigatran group (p = 0.691).

CONCLUSIONS

The efficacy and safety were comparable between rivaroxaban and dabigatran in the treatment of cirrhotic patients with acute portal vein thrombosis. And D-dimer can contribute to the prediction of PVT recanalization in cirrhotic patients.

Management of Patients Treated with Direct Oral Anticoagulants in Clinical Practice and Challenging Scenarios

It is well established that direct oral anticoagulants (DOACs) are the cornerstone of anticoagulant strategy in atrial fibrillation (AF) and venous thromboembolism (VTE) and should be preferred over vitamin K antagonists (VKAs) since they are superior or non-inferior to VKAs in reducing thromboembolic risk and are associated with a lower risk of intracranial hemorrhage (IH). In addition, many factors, such as fewer pharmacokinetic interactions and less need for monitoring, contribute to the favor of this therapeutic strategy. Although DOACs represent a more suitable option, several issues should be considered in clinical practice, including drug-drug interactions (DDIs), switching to other antithrombotic therapies, preprocedural and postprocedural periods, and the use in patients with chronic renal and liver failure and in those with cancer. Furthermore, adherence to DOACs appears to remain suboptimal. This narrative review aims to provide a practical guide for DOAC prescription and address challenging scenarios.

ABCG2 Gene Polymorphisms May Affect the Bleeding Risk in Patients on Apixaban and Rivaroxaban

Purpose

Direct oral anticoagulants (DOACs) are widely used for stroke prevention in atrial fibrillation. However, they have a bleeding complication. Breast cancer resistance protein, encoded by ABCG2, is known to be an efflux transporter of apixaban and rivaroxaban among DOACs. This study aimed to investigate the association between gene variants and bleeding complications during treatment with ABCG2 substrates (apixaban and rivaroxaban).

Patients and Methods

Patients treated with apixaban and rivaroxaban were enrolled from June 2018 to December 2021. Five single nucleotide polymorphisms (SNPs) of ABCG2 were selected. Previously studied genes (ABCB1, CYP3A4, and CYP3A5) were further analyzed as possible confounders. Finally, a total of 16 SNPs were examined in this case-control study. The outcome was defined as major bleeding and clinically relevant non-major bleeding. Two models were constructed using the multivariable analysis.

Results

Among 293 patients, 64 were cases. The mean age of the patients was 68.8 years, and males comprised 62.5% of the study population. Model I revealed that a history of bleeding, concurrent use of proton pump inhibitor (PPI), ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with bleeding complications; the AORs (95% CI) were 6.209 (2.210-17.442), 2.385 (1.064-5.349), 2.188 (1.156-4.142), and 3.243 (1.371-7.671), respectively. Model II showed that modified HAS-BLED score, concurrent use of PPI, ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with bleeding complications.

Conclusion

The modified HAS-BLED score, a history of bleeding, concurrent use of PPI, ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with the risk of bleeding complications in patients on apixaban and rivaroxaban, after adjusting for other confounders. These findings can be used to develop individualized treatment strategies for patients taking apixaban and rivaroxaban.

Non-major bleeding risk of direct oral anticoagulants versus vitamin K antagonists for stroke prevention with atrial fibrillation: a systematic review and network meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs) are associated with bleeding. Patients often stop taking DOACs due to non-major bleeding, which may lead to stroke recurrence. We aimed to determine the risk of non-major bleeding using different DOACs to prevent strokes in atrial fibrillation (AF).

METHODS

A systematic search of four databases (PubMed, EMBASE, Web of Science, and Cochrane Library) was performed to identify randomized controlled trials (RCTs) reporting non-major bleeding events in patients taking DOACs or vitamin K antagonists (VKAs). In this frequency-based network meta-analysis, odds ratios and 95% confidence intervals were used for reporting. Based on the surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Nineteen randomized controlled trials (RCTs) (involving 85,826 patients) were included. For clinically relevant non-major bleeding, the risk for bleeding was lowest for apixaban (SUCRA, 93.9), followed by that for VKAs (SUCRA, 47.7), dabigatran (SUCRA, 40.3), rivaroxaban (SUCRA, 35.9), and edoxaban (SUCRA, 32.2). The minor bleeding safety of DOACs was ranked from highest to lowest as follows: apixaban (SUCRA, 78.1), edoxaban (SUCRA, 69.4), dabigatran (SUCRA, 48.8), and VKAs (SUCRA, 3.7).

CONCLUSIONS

Based on current evidence, for stroke prevention in patients with AF, the safest DOAC is apixaban in terms of non-major bleeding. This suggests that apixaban may have a lower risk of non-major bleeding than other anticoagulants and may help provide some clinical reference for choosing a more appropriate drug for the patient.

Association of Alternative Anticoagulation Strategies and Outcomes in Patients With Ischemic Stroke While Taking a Direct Oral Anticoagulant

BACKGROUND AND OBJECTIVES

Ischemic stroke despite a direct oral anticoagulant (DOAC) is increasingly common and portends a high risk of subsequent ischemic stroke. The efficacy and safety of antithrombotic regimens after the condition are unclear. We aimed to compare the outcomes of patients with ischemic stroke despite DOACs with and without an alternative antithrombotic regimen and determine the risk factors of recurrent ischemic stroke while on anticoagulation.

METHODS

In a population-based, propensity score-weighted, retrospective cohort study, we compared the clinical outcomes of DOAC-to-warfarin switch, DOAC-to-DOAC switch (DOACswitch), or addition of antiplatelet agents, with those of unchanged DOAC regimen (DOACsame) among patients with nonvalvular atrial fibrillation (NVAF) who developed the first ischemic stroke despite a DOAC from January 1, 2015, to December 31, 2020, in Hong Kong. The primary outcome was recurrent ischemic stroke. Secondary outcomes were intracranial hemorrhage, acute coronary syndrome, and death. We performed competing risk regression analyses to compare the clinical endpoints and determined the predictors of recurrent ischemic stroke in an unweighted multivariable logistic regression model.

RESULTS

During the 6-year study period, among 45,946 patients with AF on a DOAC as stroke prophylaxis, 2,908 patients developed ischemic stroke despite a DOAC. A total of 2,337 patients with NVAF were included in the final analyses. Compared with DOACsame, warfarin (aHR 1.96, 95% CI 1.27-3.02, p = 0.002) and DOACswitch (aHR 1.62, 95% CI 1.25-2.11, p < 0.001) were associated with an increased risk of recurrent ischemic stroke. In the DOACsame group, adjunctive antiplatelet agent was not associated with a reduced risk of recurrent ischemic stroke. Diabetes mellitus, concurrent cytochrome P450/P-glycoprotein (CYP/P-gp) modulators, and large artery atherosclerotic disease (LAD) were predictors of recurrent ischemic stroke.

DISCUSSION

In patients with NVAF with ischemic stroke despite a DOAC, the increased risk of recurrent ischemic stroke with switching to warfarin called for caution against such practice, while the increased ischemic stroke with DOAC-to-DOAC switch demands further studies. Adjunctive antiplatelet agent did not seem to reduce ischemic stroke relapse. Because diabetes mellitus, the use of CYP/P-gp modulators, and LAD were predictors of recurrent ischemic stroke, further investigations should evaluate whether strict glycemic control, DOAC level monitoring, and routine screening for carotid and intracranial atherosclerosis may reduce ischemic stroke recurrence in these patients.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in patients with NVAF experiencing an ischemic stroke while being treated with a DOAC, continuing treatment with that DOAC is more effective at preventing recurrent ischemic stroke than switching to a different DOAC or to warfarin.

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.

Direct Oral Anticoagulant Failures in Atrial Fibrillation With Stroke: Retrospective Admission Analysis and Novel Classification System

Introduction

Breakthrough acute ischemic stroke (AIS) in patients with known, nonvalvular Atrial Fibrillation (AF), on Direct Oral Anticoagulants (DOAC), is an ongoing clinical conundrum. Switching anticoagulants was shown to be ineffective in preventing recurrent AIS. Systematic, patient-level chart review of so-called "DOAC failures" may offer insight into this phenomenon.

Methods

We conducted an IRB-approved, 6-year, retrospective study of AIS admissions, already prescribed DOAC for known AF. We sought plausible, alternative reasons for the AIS using a novel classification schema, CLAMP: C for Compliance concerns, L for Lacunes (small-vessel disease), A for Arteriopathy (atherosclerosis, web, or vasculitis), M for Malignancy, and P for Patent Foramen Ovale (PFO). These categories were labeled as DOAC "Pseudo-failures." Conversely, absence of CLAMP variables were labeled as DOAC "Crypto-failures" conceivably from AF itself ("atriopathy") or pharmacokinetic/pharmacogenomic dysfunction (ie, altered DOAC absorption, clearance, metabolism, or genetic polymorphisms). Forward logistic regression analysis was performed on prespecified DOAC subgroups.

Results

Of 4890 AIS admissions, 606 had AF, and 87 were previously prescribed DOAC (14.4% overall DOAC failure rate, 2.4% annualized over 6 years). Pseudo-failures comprised 77%: Compliance concerns (48.9%), Lacunes (5.7%), Arteriopathy (17.0%), Malignancy (26.1%), and PFO (2.3%). Crypto-failures comprised 23%, had lower CHADSVASc scores (AOR = .65, P = .013), and occurred more with rivaroxaban (41%) than apixaban (16%) or dabigatran (5.6%).

Conclusion

In AIS patients with known AF, DOAC Pseudo-failures, with identified alternate etiologies, are 3 times more likely than DOAC Crypto-failures. The CLAMP schema represents a novel approach to diagnostic classification and therapeutic adjustments in patients already prescribed DOAC for AF.

Phenotype-directed clinically driven low-dose direct oral anticoagulant for atrial fibrillation

Clinically-driven dose reduction of direct oral anticoagulants in individuals with atrial fibrillation is prevalent worldwide. However, a paucity of evidence to tailor dose selection remained as clinical unmet need. Current doses of anticoagulant were determined largely by landmark clinical trials, in which the enrolled subjects were carefully selected and without major comorbidities. Our study reviewed the relevant real-world studies in specific patient phenotypes, including renal and hepatic diseases, elderly, low body weight, Asians and presence of concomitant drug-drug interactions. Thorough investigations toward the efficacy and safety of direct oral anticoagulants in reduced doses will facilitate substituting current universal approach with individualized prescriptions.

The Distribution of the Genotypes of ABCB1 and CES1 Polymorphisms in Kazakhstani Patients with Atrial Fibrillation Treated with DOAC

Nowadays, direct oral anticoagulants (DOACs) are the first-line anticoagulant strategy in patients with non-valvular atrial fibrillation (NVAF). We aimed to identify the influence of polymorphisms of the genes encoding P-glycoprotein (ABCB1) and carboxylesterase 1 (CES1) on the variability of plasma concentrations of DOACs in Kazakhstani patients with NVAF. We analyzed polymorphisms rs4148738, rs1045642, rs2032582 and rs1128503 in ABCB1 and rs8192935, rs2244613 and rs71647871 CES1 genes and measured the plasma concentrations of dabigatran/apixaban and biochemical parameters in 150 Kazakhstani NVAF patients. Polymorphism rs8192935 in the CES1 gene (p = 0.04), BMI (p = 0.01) and APTT level (p = 0.01) were statistically significant independent factors of trough plasma concentration of dabigatran. In contrast, polymorphisms rs4148738, rs1045642, rs2032582 and rs1128503 in ABCB1 and rs8192935, rs2244613 and rs71647871 CES1 genes did not show significant influence on plasma concentrations of dabigatran/apixaban drugs (p > 0.05). Patients with GG genotype (138.8 ± 100.1 ng/mL) had higher peak plasma concentration of dabigatran than with AA genotype (100.9 ± 59.6 ng/mL) and AG genotype (98.7 ± 72.3 ng/mL) (Kruskal-Wallis test, p = 0.25). Thus, CES1 rs8192935 is significantly associated with plasma concentrations of dabigatran in Kazakhstani NVAF patients (p < 0.05). The level of the plasma concentration shows that biotransformation of the dabigatran processed faster in individual carriers of GG genotype rs8192935 in the CES1 gene than with AA genotype.

Severe Bleeding Risk of Direct Oral Anticoagulants Versus Vitamin K Antagonists for Stroke Prevention and Treatment in Patients with Atrial Fibrillation: A Systematic Review and Network Meta-Analysis

PURPOSE

We aimed to determine the safety of direct oral anticoagulants (DOACs) for stroke prevention and treatment in patients with atrial fibrillation (AF).

METHODS

A systematic search of four databases (PubMed, EMBASE, Web of Science, and Cochrane Library) was performed to identify randomized controlled trials (RCTs) reporting severe bleeding events in patients taking DOACs or vitamin K antagonists (VKAs). In this frequency-based network meta-analysis, odds ratios and 95% confidence intervals were used for reporting. Based on the surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Twenty-three RCTs met the inclusion criteria, and a total of 87,616 patients were enrolled. The bleeding safety of DOACs for stroke prevention and treatment in patients with AF was ranked from highest to lowest as follows: fatal bleeding: edoxaban (SUCRA,80.2), rivaroxaban (SUCRA,68.3), apixaban (SUCRA,48.5), dabigatran (SUCRA,40.0), VKAs (SUCRA,12.9); major bleeding: dabigatran (SUCRA,74.0), apixaban (SUCRA,71.5), edoxaban (SUCRA,66.5), rivaroxaban (SUCRA,22.7), VKAs (SUCRA,15.4); gastrointestinal bleeding: apixaban (SUCRA,55.9), VKAs (SUCRA,53.7), edoxaban (SUCRA,50.5), rivaroxaban (SUCRA,50.4), dabigatran (SUCRA,39.5); intracranial hemorrhage: dabigatran (SUCRA,84.6), edoxaban (SUCRA,74.1), apixaban (SUCRA,65.8), rivaroxaban (SUCRA,24.4), VKAs (SUCRA,1.1).

CONCLUSION

Based on current evidence, for stroke prevention and treatment in patients with AF, the most safe DOAC is edoxaban in terms of fatal bleeding; dabigatran in terms of major bleeding and intracranial hemorrhage and apixaban in terms of gastrointestinal bleeding. However, given the nature of indirect comparisons, more high-quality evidence from head-to-head comparisons is still needed to confirm them.

Effect of Genotype on the Pharmacokinetics and Bleeding Events of Direct Oral Anticoagulants: A Systematic Review and Meta-analysis

This meta-analysis aimed to investigate the effect of the genotype on the pharmacokinetics and bleeding events of direct oral anticoagulants (DOACs) and comprehensively searched electronic databases. Weighted mean difference (WMD) was used to assess the kinetic indicators, odds ratio, and 95% confidence interval (CI) were used to calculate the clinical outcomes. Thirteen articles with 1543 participants were finally included in this study. The peak concentration (C_max ) and area under the plasma concentration-time curve from time 0 to infinity of individuals with the ABCB1 rs 1045642 CT + TT were higher than that of the CC (WMD = -31.9, 95% CI [-49.94, -12.24], P = .02; WMD = -79.97, 95%CI [-152.38 to -7.56], P = .03, I² = 0). The C_max of individuals with mutated genes in ABCB1 2677-3435 is higher than that the wild type (WMD = -19.20, 95%CI [36.62 to -1.79], P = .03, I² = 0). Carriers of the CYP3A5 rs776746 GG genotype had a higher C_max than the GA gene (WMD = -51.22, 95%CI [-92.26 to -10.19], P = .01, I² = 0). Bleeding events were more common in the CES1 rs 2244613 AA + AC than in the CC (odds ratio, 2.62, 95%CI [1.06, 6.47], P = .04; I² = 0). The C_max of DOACs was affected by individuals with ABCB1 rs 1045642, ABCB1 2677-343, and cytochrome P450 3A5 rs 776746. Carriers of the ABCB1 rs 1045642 affected the change of area under the plasma concentration-time curve from time 0 to infinity of DOACs. Bleeding events were affected by CES1 rs 2244613.

Direct Oral Anticoagulants use in Patients with Stable Coronary Artery Disease, Acute Coronary Syndrome or Undergoing Percutaneous Coronary Intervention

The investigation for the optimal anticoagulation strategy for patients with stable coronary artery disease, acute coronary syndromes, and undergoing percutaneous coronary intervention constitutes a great challenge for physicians and is a field of extensive research. Although aspirin is commonly recommended as a protective measure for all patients with coronary artery disease and dual antiplatelet therapy for those undergoing procedures, such as percutaneous coronary intervention or coronary artery bypass graft surgery, the risk of recurrent cardiovascular events remains significant. In this context, the shortcomings associated with the use of vitamin K antagonists have led to the assessment of direct oral anticoagulants as promising alternatives. This review will explore and provide a comprehensive analysis of the existing data regarding the use of direct oral anticoagulants in patients with stable coronary artery disease or acute coronary syndrome, as well as their effectiveness in those undergoing percutaneous coronary intervention or coronary artery bypass graft surgery.

Predicting disruptions to drug pharmacokinetics and the risk of adverse drug reactions in non-alcoholic steatohepatitis patients

The liver plays a central role in the pharmacokinetics of drugs through drug metabolizing enzymes and transporters. Non-alcoholic steatohepatitis (NASH) causes disease-specific alterations to the absorption, distribution, metabolism, and excretion (ADME) processes, including a decrease in protein expression of basolateral uptake transporters, an increase in efflux transporters, and modifications to enzyme activity. This can result in increased drug exposure and adverse drug reactions (ADRs). Our goal was to predict drugs that pose increased risks for ADRs in NASH patients. Bibliographic research identified 71 drugs with reported ADRs in patients with liver disease, mainly non-alcoholic fatty liver disease (NAFLD), 54 of which are known substrates of transporters and/or metabolizing enzymes. Since NASH is the progressive form of NAFLD but is most frequently undiagnosed, we identified other drugs at risk based on NASH-specific alterations to ADME processes. Here, we present another list of 71 drugs at risk of pharmacokinetic disruption in NASH, based on their transport and/or metabolism processes. It encompasses drugs from various pharmacological classes for which ADRs may occur when used in NASH patients, especially when eliminated through multiple pathways altered by the disease. Therefore, these results may inform clinicians regarding the selection of drugs for use in NASH patients.

Genetic variations in relation to bleeding and pharmacodynamics of dabigatran in Chinese patients with nonvalvular atrial fibrillation: A nationwide multicentre prospective cohort study

INTRODUCTION

To identify the potential factors responsible for the individual variability of dabigatran, we investigated the genetic variations associated with clinical outcomes and pharmacodynamics (PD) in Chinese patients with nonvalvular atrial fibrillation (NVAF).

MATERIALS AND METHODS

Chinese patients with NVAF taking dabigatran etexilate with therapeutic doses were enrolled. The primary (bleeding events) and secondary (thromboembolic and major adverse cardiac events) outcomes for a 2-year follow-up were evaluated. Peak and trough PD parameters (anti-FIIa activity, activated partial thromboplastin time and prothrombin time) were detected. Whole-exome sequencing, genome-wide sequencing and candidate gene association analyses were performed.

RESULTS

There were 170 patients with NVAF treated with dabigatran (110 mg twice daily) who were finally included. Two single-nucleotide polymorphisms (SNPs) were significantly related with bleeding, which include UBASH3B rs2276408 (odds ratio [OR] = 8.79, 95% confidence interval [CI]: 2.99-25.83, p = 7.77 × 10-5 at sixth month visit) and FBN2 rs3805625 (OR = 8.29, 95% CI: 2.87-23.89, p = 9.08 × 10-5 at 12th month visit), as well as with increased trends at other visits (p < .05). Furthermore, minor allele carriers of 16 new SNPs increased PD levels, and those of one new SNP decreased PD values (p < 1.0 × 10-5 ). Lastly, 33 new SNPs were found to be associated with bleeding and PD among 14 candidate genes. Unfortunately, the low number of secondary outcomes precluded further association analyses.

CONCLUSIONS

Genetic variations indeed affected bleeding and PD in Chinese patients with NVAF treated with dabigatran. The functions of these suggestive genes and SNPs might further be explored and verified in more in vivo and in vitro investigations.

Impact of concomitant fluconazole on direct oral anticoagulant bleeding risk

STUDY OBJECTIVE

The aim of this study was to evaluate the effect on bleeding risk when fluconazole is administered concomitantly with direct oral anticoagulants (DOACs).

DESIGN

This was a retrospective cohort study including hospitalized adult patients prescribed a DOAC with or without fluconazole.

SETTING

The Ohio State University Wexner Medical Center, a tertiary care academic medical center with more than 1800 beds.

PATIENTS

Hospitalized patients ages 18-89 years who received apixaban or rivaroxaban with or without fluconazole from October 1, 2016, to September 30, 2021, were included. The minimum duration of DOAC or DOAC with fluconazole therapy was 48 h. Patients were excluded if they received fluconazole <400 mg daily or a DOAC at doses outside those recommended for atrial fibrillation or venous thromboembolism treatment or prophylaxis. Patients were matched based on DOAC received.

INTERVENTION

Patients who received a DOAC with fluconazole were compared with those receiving a DOAC alone. The primary outcome was a composite of major, clinically relevant nonmajor, and minor bleeding events at 30 days.

MEASUREMENTS AND MAIN RESULTS

There were 216 patients included, 108 in the DOAC with fluconazole group and 108 in the DOAC alone group. More patients in the DOAC with fluconazole group experienced bleeding at 30 days compared with the DOAC alone group [35/108 (32%) vs. 21/108 (19%), respectively; p = 0.03]; however, after adjusting for proven confounding variables (hemoglobin and concomitant carvedilol) this was found not to be statistically significant [adjusted odds ratio 1.71, 95% confidence interval 0.85-3.40].

CONCLUSIONS

Patients receiving a DOAC with fluconazole were not at significantly increased risk for bleeding at 30 days compared with those receiving a DOAC alone after controlling for confounding variables. As an increasing number of patients are prescribed DOACs, the results of this study may inform clinical decision-making on the safety of concomitant DOAC and fluconazole use.

Risk of nonmajor bleeding upon use of direct oral anticoagulants for preventing and treating venous thromboembolism: A network meta-analysis

INTRODUCTION

Direct oral anticoagulants (DOACs) are associated with bleeding. Patients often stop taking DOACs due to nonmajor bleeding, which may lead to venous thromboembolism (VTE) recurrence. We aimed to determine the risk of nonmajor bleeding using different DOACs to prevent and treat VTE.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library databases were searched from inception until January 6, 2021. The incidence of clinically relevant nonmajor bleeding and minor bleeding was investigated. In frequentist-based network meta-analysis, we analyzed the odds ratio (OR) with 95% CI and the surface under the cumulative ranking curves (SUCRA).

RESULTS

Twenty-seven randomized controlled trials (RCTs) (involving 64,493 patients) were included. For preventing VTE, the risk for clinically relevant nonmajor bleeding was lowest for apixaban, followed by that for low-molecular weight heparin (LMWH), dabigatran, edoxaban, and rivaroxaban. The risk for minor bleeding was lowest for apixaban, followed by that for rivaroxaban, LMWH, dabigatran, and edoxaban. For treating VTE, the risk for clinically relevant nonmajor bleeding was also lowest for apixaban, followed by that for edoxaban, vitamin K antagonists (VKAs), and rivaroxaban. The risk for minor bleeding was lowest for apixaban, followed by that for rivaroxaban and VKAs.

CONCLUSIONS

Regardless of whether it was used for preventing or treating VTE, apixaban had the lowest risk of nonmajor bleeding. This suggests that apixaban may have a lower risk of nonmajor bleeding than other anticoagulants and may help provide some clinical reference for choosing a more appropriate drug for the patient.

Genetic determinants of apixaban plasma levels and their relationship to bleeding and thromboembolic events

Apixaban is a direct oral anticoagulant, a factor Xa inhibitor, used for the prevention of ischemic stroke in patients with atrial fibrillation. Despite using recommended dosing a few patients might still experience bleeding or lack of efficacy that might be related to inappropriate drug exposure. We conducted a genome-wide association study using data from 1,325 participants in the pivotal phase three trial of apixaban with the aim to identify genetic factors affecting the pharmacokinetics of apixaban. A candidate gene analysis was also performed for pre-specified variants in ABCB1, ABCG2, CYP3A4, CYP3A5, and SULT1A1, with a subsequent analysis of all available polymorphisms within the candidate genes. Significant findings were further evaluated to assess a potential association with clinical outcome such as bleeding or thromboembolic events. No variant was consistently associated with an altered apixaban exposure on a genome-wide level. The candidate gene analyses showed a statistically significant association with a well-known variant in the drug transporter gene ABCG2 (c.421G &gt; T, rs2231142). Patients carrying this variant had a higher exposure to apixaban [area under the curve (AUC), beta = 151 (95% CI 59–243), p = 0.001]. On average, heterozygotes displayed a 5% increase of AUC and homozygotes a 17% increase of AUC, compared with homozygotes for the wild-type allele. Bleeding or thromboembolic events were not significantly associated with ABCG2 rs2231142. This large genome-wide study demonstrates that genetic variation in the drug transporter gene ABCG2 is associated with the pharmacokinetics of apixaban. However, the influence of this finding on drug exposure was small, and further studies are needed to better understand whether it is of relevance for ischemic and bleeding events.

Pharmacogenomic Biomarkers

Why does the usual dose of medication work for a person while another individual cannot give the expected response to the same drug? On the other hand, how come half of the usual dose of an analgesic relieves an individual’s pain immediately, as another man continue to suffer even after taking double dose? Although a treatment method has been successfully used in majority of the population for many years, why does the same therapy cause serious side effects in another region of the world? Most presently approved therapies are not effective in all patients. For example, 20-40% of patients with depression respond poorly or not at all to antidepressant drug therapy. Many patients are resistant to the effects of antiasthmatics and antiulcer drugs or drug treatment of hyperlipidemia and many other diseases. The reason for all those is basically interindividual differences in genomic structures of people, which are explained in this chapter in terms of the systems and the most frequently used drugs in clinical treatment.

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.

SLC4A4, FRAS1, and SULT1A1 Genetic Variations Associated With Dabigatran Metabolism in a Healthy Chinese Population

Background: The purpose of this study was to identify genetic variations associated with the metabolism of dabigatran in healthy Chinese subjects, with particular focus given to pharmacokinetics (PK) and pharmacodynamics (PD).

Methods: Healthy Chinese adults aged 18–65 years with unknown genotypes from a bioequivalence trial were included according to the protocol registered at ClinicalTrial.org (NCT03161496). All subjects received a single dose (150 mg) of dabigatran etexilate. PK (main outcomes: area under the concentration-time, AUC0-t, of total and free dabigatran) and PD (main outcomes: anti-FIIa activity, APTT, and PT) parameters were evaluated. Whole-exome sequencing and genome-wide association analyses were performed. Additionally, candidate gene association analyses related to dabigatran were conducted.

Results: A total of 118 healthy Chinese subjects were enrolled in this study. According to the p-value suggestive threshold (1.0 × 10−4), the following three SNPs were found to be associated with the AUC0–t of total dabigatran: SLC4A4 SNP rs138389345 (p = 5.99 × 10−5), FRAS1 SNP rs6835769 (p = 6.88 × 10−5), and SULT1A1 SNP rs9282862 (p = 7.44 × 10−5). Furthermore, these SNPs were also found to have significant influences on the AUC0–t of free dabigatran, maximum plasma concentration, and anti-FIIa activity (p &lt; 0.05). Moreover, we identified 30 new potential SNPs of 13 reported candidate genes (ABCB1, ABCC2, ABCG2, CYP2B6, CYP1A2, CYP2C19, CYP3A5, CES1, SLCO1B1, SLC22A1, UGT1A1, UGT1A9, and UGT2B7) that were associated with drug metabolism.

Conclusion: Genetic variations were indeed found to impact dabigatran metabolism in a population of healthy Chinese subjects. Further research is needed to explore the more detailed functions of these SNPs. Additionally, our results should be verified in studies that use larger sample sizes and investigate other ethnicities.

Rapid Assay for the Therapeutic Drug Monitoring of Edoxaban

Edoxaban is a direct oral anticoagulant (DOAC) that has been recently indicated for the treatment of pulmonary embolism (PE) in SARS-CoV-2 infections. Due to its pharmacokinetic variability and a narrow therapeutic index, the safe administration of the drug requires its therapeutic drug monitoring (TDM) in patients receiving the treatment. In this work, we present a label-free method for the TDM of edoxaban by surface enhanced Raman spectroscopy (SERS). The new method utilises the thiol chemistry of the drug to chemisorb its molecules onto a highly sensitive SERS substrate. This leads to the formation of efficient hotspots and a strong signal enhancement of the drug Raman bands, thus negating the need for a Raman reporter for its SERS quantification. The standard samples were run with a concentration range of 1.4 × 10⁻⁴ M to 10⁻¹² M using a mobile phase comprising of methanol/acetonitrile (85:15 v/v) at 291 nm followed by the good linearity of R² = 0.997. The lowest limit of quantification (LOQ) by the SERS method was experimentally determined to be 10⁻¹² M, whereas LOQ for HPLC-UV was 4.5 × 10⁻⁷ M, respectively. The new method was used directly and in a simple HPLC-SERS assembly to detect the drug in aqueous solutions and in spiked human blood plasma down to 1 pM. Therefore, the SERS method has strong potential for the rapid screening of the drug at pathology labs and points of care.

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.

Pharmacogenetics and Precision Medicine Approaches for the Improvement of COVID-19 Therapies

Many drugs are being administered to tackle coronavirus disease 2019 (COVID-19) pandemic situations without establishing clinical effectiveness or tailoring safety. A repurposing strategy might be more effective and successful if pharmacogenetic interventions are being considered in future clinical studies/trials. Although it is very unlikely that there are almost no pharmacogenetic data for COVID-19 drugs, however, from inferring the pharmacokinetic (PK)/pharmacodynamic(PD) properties and some pharmacogenetic evidence in other diseases/clinical conditions, it is highly likely that pharmacogenetic associations are also feasible in at least some COVID-19 drugs. We strongly mandate to undertake a pharmacogenetic assessment for at least these drug–gene pairs (atazanavir–UGT1A1, ABCB1, SLCO1B1, APOA5; efavirenz–CYP2B6; nevirapine–HLA, CYP2B6, ABCB1; lopinavir–SLCO1B3, ABCC2; ribavirin–SLC28A2; tocilizumab–FCGR3A; ivermectin–ABCB1; oseltamivir–CES1, ABCB1; clopidogrel–CYP2C19, ABCB1, warfarin–CYP2C9, VKORC1; non-steroidal anti-inflammatory drugs (NSAIDs)–CYP2C9) in COVID-19 patients for advancing precision medicine. Molecular docking and computational studies are promising to achieve new therapeutics against SARS-CoV-2 infection. The current situation in the discovery of anti-SARS-CoV-2 agents at four important targets from in silico studies has been described and summarized in this review. Although natural occurring compounds from different herbs against SARS-CoV-2 infection are favorable, however, accurate experimental investigation of these compounds is warranted to provide insightful information. Moreover, clinical considerations of drug–drug interactions (DDIs) and drug–herb interactions (DHIs) of the existing repurposed drugs along with pharmacogenetic (e.g., efavirenz and CYP2B6) and herbogenetic (e.g., andrographolide and CYP2C9) interventions, collectively called multifactorial drug–gene interactions (DGIs), may further accelerate the development of precision COVID-19 therapies in the real-world clinical settings.

Impact of Drug Interactions on Major Bleed Rates in Patients Taking Direct Oral Anticoagulants

Background: While direct oral anticoagulants (DOACs) have less stringent monitoring, favorable pharmacokinetics, and fewer drug interactions compared to warfarin, there is still a potential for drug–drug interactions. There is limited evidence showing total impact of DOAC drug interactions on major bleeding events. Methods: This was an IRB-approved retrospective, case control, single center study. Patients were included if they had received a DOAC from January 2012 to September 2019 and were identified for major bleeding events and matched to a control group. The primary objective was to compare the presence of major drug interactions between patients on DOACs who did and did not have a major bleeding event. The secondary objectives were to compare the impact of specific interacting drug classes and their additive effects on major bleeding events. Results: There were 122 patients included in the study. While the number of patients on at least one interacting medication within duration of DOAC use was numerically higher in the bleed group (85% vs 72%), this was not significant (P = .077). There were significantly more patients on at least three interacting medications within the last 3 months of the study period in the bleed group (n = 9 vs 1), with significantly higher use of aspirin (n = 38 vs 17) and rate control agents (n = 24 vs 11). Conclusion: There may be a cumulative effect on risk of bleeding if patients are on three or more interacting medications concomitantly with a DOAC. This risk of bleeding may be higher with aspirin and rate control agents.

Genetic Factors of Renin–Angiotensin System Associated with Major Bleeding for Patients Treated with Direct Oral Anticoagulants

The purpose of this study was to identify the renin–angiotensin system (RAS)-related genetic factors associated with bleeding and develop the bleeding risk scoring system in patients receiving direct oral anticoagulants (DOACs). This study was a retrospective analysis of prospectively collected samples from June 2018 to May 2020. To investigate the associations between RAS-related genetic factors and major bleeding, we selected 16 single nucleotide polymorphisms (SNPs) from five genes (namely, AGT, REN, ACE, AGTR1, and AGTR2). Multivariable logistic regression analysis was employed to investigate the independent risk factors for bleeding and to develop a risk scoring system. A total of 172 patients were included in the analysis, including 33 major bleeding cases. Both old age (≥65 years) and moderate to severe renal impairment (CrCl < 50 mL/min) increased the risk of bleeding in the multivariable analysis. Among RAS-related polymorphisms, patients carrying TT genotype of rs5050 and A allele of rs4353 experienced a 3.6-fold (95% CI: 1.4–9.3) and 3.1-fold (95% CI: 1.1–9.3) increase in bleeding, respectively. The bleeding risk increased exponentially with a higher score; the risks were 0%, 2.8%, 16.9%, 32.7%, and 75% in patients with 0, 1, 2, 3, and 4 points, respectively. Although this study is limited to a retrospective study design, this is the first study to suggest RAS-related genetic markers and risk scoring systems, including both clinical and genetic factors, for major bleeding in patients receiving DOAC treatment.

Pharmacogenomics Informs Cardiovascular Pharmacotherapy

Precision medicine exemplifies the emergence of personalized treatment options which may benefit specific patient populations based upon their genetic makeup. Application of pharmacogenomics requires an understanding of how genetic variations impact pharmacokinetic and pharmacodynamic properties. This particular approach in pharmacotherapy is helpful because it can assist in and improve clinical decisions. Application of pharmacogenomics to cardiovascular pharmacotherapy provides for the ability of the medical provider to gain critical knowledge on a patient's response to various treatment options and risk of side effects.

Is this the beginning of end for warfarin in bioprosthetic mitral valve recipients with atrial fibrillation? - New insights from RIVER trial

Novel oral anticoagulants, with dabigatran in particular have failed in their quest to replace the traditional anticoagulation in the form of vitamin K antagonist in patients with mechanical valvular implants. However, the same had not been tried in bioprosthetic valve recipients until recently in a large trial where rivaroxaban was found to be non-inferior to warfarin on head-to-head basis. This commentary discusses the various aspects related to oral anticoagulation in bioprosthetic valve recipients in the light of recent clinical evidence.

Pharmacogenetics of Bleeding and Thromboembolic Events in Direct Oral Anticoagulant Users

This study aimed to analyze associations between genetic variants and the occurrence of clinical outcomes in dabigatran, apixaban, and rivaroxaban users. This was a retrospective real-world study linking genotype data of three Finnish biobanks with national register data on drug dispensations and healthcare encounters. We investigated several single-nucleotide variants (SNVs) in the ABCG2, ABCB1, CES1, and CYP3A5 genes potentially associated with bleeding or thromboembolic events in direct oral anticoagulant (DOAC) users based on earlier research. We used Cox regression models to compare the incidence of clinical outcomes between carriers and noncarriers of the SNVs or haplotypes. In total, 1,806 patients on apixaban, dabigatran, or rivaroxaban were studied. The ABCB1 c.3435C>T (p.Ile1145=, rs1045642) SNV (hazard ratio (HR) 0.42, 95% confidence interval (CI), 0.18-0.98, P = 0.044) and 1236T-2677T-3435T (rs1128503-rs2032582-rs1045642) haplotype (HR 0.44, 95% CI, 0.20-0.95, P = 0.036) were associated with a reduced risk for thromboembolic outcomes, and the 1236C-2677G-3435C (HR 2.55, 95% CI, 1.03-6.36, P = 0.044) and 1236T-2677G-3435C (HR 5.88, 95% CI, 2.35-14.72, P < 0.001) haplotypes with an increased risk for thromboembolic outcomes in rivaroxaban users. The ABCB1 c.2482-2236G>A (rs4148738) SNV associated with a lower risk for bleeding events (HR 0.37, 95% CI, 0.16-0.89, P = 0.025) in apixaban users. ABCB1 variants are potential factors affecting thromboembolic events in rivaroxaban users and bleeding events in apixaban users. Studies with larger numbers of patients are warranted for comprehensive assessment of the pharmacogenetic associations of DOACs and their relevance for clinical practice.

Efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism: a meta-analysis

Objective

Several trials had compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin for acute venous thromboembolism, but the results were incomplete. This updated review comprehensively assessed the efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism.

Design

Meta-analysis of randomised control trials. Six databases were searched from January 2000 to December 2018.

Setting

Adult patients had got non-vitamin K antagonist oral anticoagulants or warfarin for venous thromboembolism.

Participants

Randomised control trials that compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin.

Main outcome measures

The efficacy and safety of non-vitamin K antagonist oral anticoagulants .

Results

Seven studies involving 29,879 cases were included, among which 14,943 cases were assigned to non-vitamin K antagonist oral anticoagulants group and 14,936 cases to warfarin group. Meta-analysis showed that compared with warfarin, recurrent venous thromboembolism (odds ratio 0.94 [95% confidence interval 0.81 to 1.11]), death related to venous thromboembolism or fatal pulmonary embolism (odds ratio 1.00 [95% confidence interval 0.63 to 1.60]), symptomatic deep-vein thrombosis (odds ratio 0.88 [95% confidence interval 0.72 to 1.09]), symptomatic nonfatal pulmonary embolism (odds ratio 1.03 [(95% confidence interval 0.82 to 1.30]) and all deaths (odds ratio 0.92 [95% confidence interval 0.76 to 1.12]) are similar in non-vitamin K antagonist oral anticoagulants group, but major bleeding event (odds ratio 0.61 [95% confidence interval 0.50 to 0.75]) and clinically relevant non-major bleeding event (odds ratio [95% confidence interval 0.53 to 0.85]) are less in non-vitamin K antagonist oral anticoagulants group. .

Conclusions

For the treatment of venous thromboembolism, non-vitamin K antagonist oral anticoagulants is as effective as warfarin, and has a better safety profile than warfarin.

Naringenin has an inhibitory effect on rivaroxaban in rats both in vitro and in vivo

Food–drug interactions are reported to have some impacts on the pharmacokinetics and pharmacodynamics of various oral drugs. To better understand the effects of naringenin, one natural product in many fruits, on the pharmacokinetics of rivaroxaban, drug–drug interactions (DDIs) between naringenin and rivaroxaban in vitro were investigated in Sprague–Dawley (SD) rat liver microsomes. For the DDIs in vivo, 12 male SD rats were randomly divided into the experimental group and the control group with six rats in each group. Rats in the experimental group were pre‐treated with naringenin (10 mg/kg/day) for 2 weeks before the administration of rivaroxaban (10 mg/kg) by oral gavage, while the rats in the control group were given rivaroxaban (10 mg/kg) only once. The plasma concentration of rivaroxaban in rats was then measured by UPLC‐MS/MS. In vitro data indicated that naringenin could decrease the metabolic clearance rate of rivaroxaban with the IC₅₀ value of 38.89 μM, and exhibited a mixed inhibition to rivaroxaban (Ki =54.91 μM, aKi =73.33 μM, a = 0.74). In vivo data in rats revealed that as compared with that of the control group, the AUC_(0–t) value of rats in the experimental group was increased from 2406.28 ± 519.69 μg/h/L to 4005.04 ± 1172.76 μg/h/L, the C_max value was increased from 310.23 ± 85.76 μg/L to 508.71 ± 152.48 μg/L, and the V_z/F and CL_z/F were decreased from 23.03 ± 4.81 L/kg to 16.2 ± 8.42 L/kg, 4.26 ± 0.91 L/h/kg to 2.57 ± 0.73 L/h/kg, respectively. These data indicated that naringenin had an inhibitory effect on the pharmacokinetics of rivaroxaban in rats, suggesting that the DDIs between naringenin and rivaroxaban might occur when they were co‐administered in the clinic.

Oral Anticoagulant Treatment in Patients with Atrial Fibrillation and Chronic Kidney Disease

Over the past few decades, a series of innovative medicines have been developed in order to optimize anticoagulation therapy for atrial fibrillation (AF). As a result, a number of nonvitamin K antagonist oral anticoagulants (NOAC) that directly target the enzymatic activity of factor II and factor Xa have been successfully licensed providing a more predictable effect and better safety profile compared to conventional anticoagulants (heparins and vitamin K antagonists (VKAs)). However, comparative efficacy and safety data is limited in patients with advanced chronic kidney disease (i.e., CKD stage 4/5 and end stage renal disease) because patients with estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m² were actively excluded from landmark trials, thus representing a major clinical limitation for the currently available agents. However, the renal function of AF patients can be altered over time. On the other hand, patients with CKD have an increased risk of developing AF. This review article will provide an overview of current concepts and recent evidence guiding the clinical use of NOACs in patients with CKD requiring chronic anticoagulation, and the associated risks and benefits of treatment in this specific patient population.

The Impact of ABCB1 and CES1 Polymorphisms on Dabigatran Pharmacokinetics in Healthy Chinese Subjects

Dabigatran is a novel direct oral anticoagulant agent, whose plasma concentration is closely related to bleeding risk. Genetic polymorphisms can affect the level of plasma dabigatran. The purpose of this study was to understand the relationship between dabigatran-related genes and the plasma level of dabigatran in healthy Chinese subjects after taking a single oral dose. This study was performed with a single-center, single-dose, randomized, open-label, and four-period crossover trial design under both fasting and fed conditions. A total of 106 eligible healthy subjects were enrolled in the study and 104 were genotyped. One-way analysis of variance (ANOVA) was used to compare pharmacokinetic parameters among different genotypes and linear regression was applied to explore the multiplicative interaction between variables. In this study, we found that the genotype frequencies of CES1 rs2244613 and CES1 rs8192935 were significantly different between Chinese and Caucasians, but the genotype frequencies of ABCB1 rs1045642 and ABCB1 rs4148738 were similar in both populations. CES1 rs8192935 were associated with the peak concentration of dabigatran. There was no significant gender difference in the exposure level of dabigatran. Furthermore, food significantly delayed the absorption of dabigatran but had little effect on C_max and AUC_0-∞.

Using Pharmacogenetics of Direct Oral Anticoagulants to Predict Changes in Their Pharmacokinetics and the Risk of Adverse Drug Reactions

Dabigatran, rivaroxaban, apixaban, and edoxaban are direct oral anticoagulants (DOACs) that are increasingly used worldwide. Taking into account their widespread use for the prevention of thromboembolism in cardiology, neurology, orthopedics, and coronavirus disease 2019 (COVID 19) as well as their different pharmacokinetics and pharmacogenetics dependence, it is critical to explore new opportunities for DOACs administration and predict their dosage when used as monotherapy or in combination with other drugs. In this review, we describe the details of the relative pharmacogenetics on the pharmacokinetics of DOACs as well as new data concerning the clinical characteristics that predetermine the needed dosage and the risk of adverse drug reactions (ADRs). The usefulness of genetic information before and shortly after the initiation of DOACs is also discussed. The reasons for particular attention to these issues are not only new genetic knowledge and genotyping possibilities, but also the risk of serious ADRs (primarily, gastrointestinal bleeding). Taking into account the effect of the carriership of single nucleotide variants (SNVs) of genes encoding biotransformation enzymes and DOACs metabolism, the use of these measures is important to predict changes in pharmacokinetics and the risk of ADRs in patients with a high risk of thromboembolism who receive anticoagulant therapy.