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Apixaban, a direct oral anticoagulant drug (DOAC), typically does not require routine therapeutic drug monitoring (TDM), yet recent guidelines propose its use in specific clinical scenarios. While various antifactor Xa (anti-FXa) chromogenic assays serve as useful proxies for measuring plasma exposure to apixaban in emergencies, they lack specificity compared with chromatographic methods. This research project is intended to the development and validation of a standardized protocol of liquid chromatography-tandem mass spectrometry (LC-MS/MS) in conformity with the ICH guidelines M10 for the measurement of apixaban in both plasma and dried plasma spots (DPSs). Samples preparation included protein precipitation after the addition of a deuterated internal standard (IS), and the chromatographic separation was carried out on a Thermo Scientific™ Accucore™ Polar Premium column (50 mm × 2.1 mm, i.d. 2.6 m). The newly developed LC-MS/MS method for apixaban mesurement from both plasma and DPS resulted linear over a wide concentration range (31.25-500 ng/mL), accurate, and reproducible without matrix effects, allowing for specific and rapid quantification. Stability was assessed on quality controls and a real sample, allowing the setting up of a robust TDM protocol that was applied to five anonymized plasma samples obtained from adult patients undergoing apixaban treatment at steady-state. In conclusion our novel LC-MS/MS method is adequate for accurate apixaban quantitation from both plasma and DPS matrixes, and may thus facilitate the guidelines suggested implementation of apixaban TDM, even in peripheral hospitals through shipment of DPS at reference laboratories., (© 2024 The Author(s). Journal of Mass Spectrometry published by John Wiley & Sons Ltd.)

Purpose: Routine therapeutic drug monitoring of apixaban is currently not recommended but may however be warranted in some situations and for some patient groups to provide better and safer treatment. Due to limited data on apixaban concentrations in different subpopulations, it is still unclear which group of patients could possibly gain from monitoring. The purpose of this study was to examine apixaban exposure in patients with obesity compared with normal-weight patients., Methods: Forty patients with obesity (mean BMI 39.4 kg/m 2 ) and 40 controls with normal weight (mean BMI 23.4 kg/m 2 ), treated with apixaban 5 mg twice daily were included. The patients were matched for age, sex, and renal function. Trough and peak apixaban concentrations were measured with LC‒MS/MS methodology., Results: The median trough concentrations in patients with obesity (58.7, range 10.7-200.7 ng/ml) were slightly higher than those in patients with normal weight (52.0, range 31.0-150.9 ng/ml) (p < 0.05). Notably, the variability in trough concentration was considerably higher in patients with obesity. Peak concentrations were similar in both groups, with a median of 124.5 ng/ml (range 82.0-277.5) and 113.5 ng/ml (range 75.5-334.6) in patients with obesity and normal weight, respectively., Conclusion: Apixaban exposure did not vary substantially between obese and normal weight matched controls, implying that general dose adjustments are not required. However, vast interindividual variability was observed in patients with obesity, suggesting that measuring the concentrations could be valuable for specific patients. Further research is needed to identify which specific patients may benefit from this approach., (© 2024. The Author(s).)

Objective: This study was the first to evaluate the effect of CYP3A4 gene polymorphisms on the plasma concentration and effectiveness of perampanel (PER) in Chinese pediatric patients with epilepsy., Methods: We enrolled 102 patients for this investigation. The steady-state concentration was determined after patients maintained a consistent PER dosing regimen for at least 21 days. Plasma PER concentrations were measured using liquid chromatography-tandem mass spectrometry. Leftover samples from standard therapeutic drug monitoring were allocated for genotyping analysis. The primary measure of efficacy was the rate of seizure reduction with PER treatment at the final check-up., Results: The CYP3A4×10 GC phenotype exhibited the highest average plasma concentration of PER at 491.1 ± 328.1 ng/mL, in contrast to the CC phenotype at 334.0 ± 161.1 ng/mL. The incidence of adverse events was most prominent in the CYP3A4×1 G TT and CYP3A4×10 GC groups, with rates of 77.8 % (7 of 9 patients) and 50.0 % (46 of 92 patients), respectively. Moreover, the percentage of patients for whom PER was deemed ineffective was least in the CYP3A4×1 G TT and CYP3A4×10 CC groups, recorded at 11.1 % (1 of 9 patients) and 10.0 % (1 of 10 patients), respectively. There was a significant correlation between PER plasma concentration and either exposure or toxicity (both with p < 0.05). We suggest a plasma concentration range of 625-900 ng/mL as a suitable reference for PER in Chinese patients with epilepsy., Conclusion: The CYP3A4×10 gene's genetic polymorphisms influence plasma concentrations of PER in Chinese pediatric patients with epilepsy. Given that both efficacy and potential toxicity are closely tied to plasma PER levels, the CYP3A4 genetic phenotype should be factored in when prescribing PER to patients with epilepsy., Competing Interests: Declaration of competing interest None of the authors have any conflict of interest to disclose. The authors confirm that they have read the Journal's policy on issues involved in ethical publication, and affirm that this study is consistent with those guidelines., (Copyright © 2024. Published by Elsevier Ltd.)

Perampanel belongs to a novel class of antiseizure medications (ASMs). Studies examining the effect of hemodialysis on perampanel serum levels in clinical settings are lacking. We aimed to evaluate the changes in serum perampanel levels during hemodialysis. We studied patients with seizures who received oral perampanel between April 2020 and March 2023 and whose serum concentration of perampanel was measured before and after hemodialysis. We analyzed the serum concentrations of levetiracetam and lacosamide for comparison. Fourteen patients, with a mean age of 76.1 ± 7.88 years, were included. The dose of perampanel was 2.14 ± 1.27 mg. The hemodialysis clearance rate of perampanel, levetiracetam, and lacosamide was 0 ± 13%, 69 ± 11%, and 59.6 ± 8.2%, respectively. The post-dialysis CD ratio decreased significantly with levetiracetam but not with perampanel. Adverse but acceptable effects of perampanel were observed in two patients. The serum concentrations of several ASMs have been shown to be reduced during hemodialysis. Our study revealed that the serum perampanel concentration does not decrease during hemodialysis. Owing to the low rate of adverse effects and the stability of perampanel serum concentration during hemodialysis, perampanel could be a favorable choice as an ASM for patients with seizures undergoing hemodialysis. PLAIN LANGUAGE SUMMARY: Our study looked at how hemodialysis affects the serum levels of perampanel, a new type of medication for seizures. In 14 patients who started treatment between April 2020 and March 2023, perampanel serum levels did not decrease during hemodialysis, unlike other seizure medications. This shows that perampanel can be a good option for patients with seizures who need hemodialysis, with fewer side effects compared to other medications., (© 2024 The Author(s). Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

The present study aimed to assess the bioequivalence of a new apixaban generic with reference formulation. Twenty-six healthy volunteers were recruited for an open-label, balanced, randomized, 2-treatment, 2-sequence, 2-period, single oral dose study. Following overnight fasting, each volunteer received 5 mg of apixaban test and reference formulations as single doses, separated by a 1-week washout period. Twenty blood samples were collected at predose and multiple time points between 0.5 and 72 hours after dosing. A validated ultra-performance liquid chromatography-tandem mass spectrometry detection method following a protein precipitation step was implemented to determine apixaban concentrations. Noncompartmental analysis was used to derive the pharmacokinetic parameters, which were then compared between the test and reference products using a multivariate analysis of variance. The pharmacokinetic parameters of the test product were not statistically different from the reference product, and the 90% confidence intervals of apixaban natural log-transformed area under the concentration-time curve from time 0 to infinity, area under the concentration-time curve from time 0 to the last measurable concentration, and maximum concentration were within 80%-125% based on the bioequivalence acceptance range criteria. The test and reference formulations of apixaban are bioequivalent in healthy subjects under fasting conditions., (© 2024, The American College of Clinical Pharmacology.)

Purpose: We assessed the differential effect of clarithromycin, a strong inhibitor of cytochrome P450 (CYP) 3A4 and P-glycoprotein, on the pharmacokinetics of a regular dose of edoxaban and on a microdose cocktail of factor Xa inhibitors (FXaI). Concurrently, CYP3A activity was determined with a midazolam microdose., Methods: In an open-label fixed-sequence trial in 12 healthy volunteers, the pharmacokinetics of a microdosed FXaI cocktail (μ-FXaI; 25 μg apixaban, 50 μg edoxaban, and 25 μg rivaroxaban) and of 60 mg edoxaban before and during clarithromycin (2 x 500 mg/d) dosed to steady-state was evaluated. Plasma concentrations of study drugs were quantified using validated ultra-performance liquid chromatography-tandem mass spectrometry methods., Results: Therapeutic clarithromycin doses increased the exposure of a therapeutic 60 mg dose of edoxaban with a geometric mean ratio (GMR) of the area under the plasma concentration-time curve (AUC) of 1.53 (90 % CI: 1.37-1.70; p < 0.0001). Clarithromycin also increased the GMR (90% CI) of the exposure of microdosed FXaI apixaban to 1.38 (1.26-1.51), edoxaban to 2.03 (1.84-2.24), and rivaroxaban to 1.44 (1.27-1.63). AUC changes observed for the therapeutic edoxaban dose were significantly smaller than those observed with the microdose (p < 0.001)., Conclusion: Clarithromycin increases FXaI exposure. However, the magnitude of this drug interaction is not expected to be clinically relevant. The edoxaban microdose overestimates the extent of the drug interaction with the therapeutic dose, whereas AUC ratios for apixaban and rivaroxaban were comparable to the interaction with therapeutic doses as reported in the literature., Trial Registration: EudraCT Number: 2018-002490-22., (© 2023. The Author(s).)

Abstract: This study evaluated perampanel pharmacokinetics and cytochrome P450 3A4 (CYP3A4) activity, assessed using the level of 4β-hydroxycholesterol (4β-OHC) as an endogenous biomarker of CYP3A4, before, during, and after pregnancy in a woman with epilepsy and compared these measurements with those from a control group of nonpregnant women with epilepsy. A 21-year-old pregnant woman was being treated with perampanel (serum concentration: 1120 ng/mL), lacosamide, and lamotrigine. After the first trimester, the lamotrigine concentration decreased markedly; however, the perampanel concentration remained almost unchanged (range, 1130-1320 ng/mL). Similarly, serum 4β-OHC levels did not change during pregnancy (before pregnancy, 78.2 ng/mL; during pregnancy, 62.2-83.2 ng/mL). To compare these measurements with those in nonpregnant women, we enrolled 27 nonpregnant women with epilepsy (age range, 16-40 years). In the control patients, we found a strong negative correlation between the concentration-to-dose ratio of perampanel and the 4β-OHC level ( r = -0.78, P < 0.001). As there was no significant change in CYP3A4 activity, we concluded that the serum perampanel concentration did not change significantly before, during, or after pregnancy. More patients need to be studied to confirm these early results., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Catheter ablation in patients with atrial fibrillation is associated with a transient increase in thromboembolic risk and adequate anticoagulation is highly important. When patients are anticoagulated with apixaban, monitoring of plasma concentrations of the drug is not routinely performed. This study aimed to assess the influence of clinical patient characteristics, concomitant drug treatment and self-reported adherence on apixaban concentrations, and to describe the intra- and inter-individual variability in apixaban concentrations in this group of patients. Method Apixaban concentrations from 141 patients were measured in plasma one week before ablation and two, six and ten weeks after ablation, employing ultra-high performance liquid chromatography coupled with tandem mass spectrometry. In samples not obtained at trough, apixaban concentrations were adjusted to trough levels. Self-reported adherence was registered by means of the 8-item Morisky Medication Adherence Scale before and after ablation., Results: There were statistically significant, positive correlations between apixaban concentrations and increased age, female sex, lower glomerular filtration rate, higher CHA2DS2-VASc score, use of cytochrome P450 3A4 and/or p-glycoprotein inhibitors, and use of amiodarone. Self-reported adherence was generally high. The mean intra-individual and inter-individual coefficients of variation were 29% and 49%, respectively., Conclusion: In patients undergoing catheter ablation for atrial fibrillation, age, sex, renal function, interacting drugs and cerebrovascular risk profile were all associated with altered plasma apixaban concentration. In this group of patients with a generally high self-reported adherence, intra-individual variability was modest, but the inter-individual variability was substantial, and similar to those previously reported in other patient apixaban-treated populations. If a therapeutic concentration range is established, there might be a need for a more flexible approach to apixaban dosing, guided by therapeutic drug monitoring., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Aakerøy et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Although antiretroviral therapy (ART) is highly effective for the treatment of HIV-1 infection to suppress virus in the blood, HIV persists in tissues. HIV persistence in the tissues is due to numerous factors, and one of those factors are antiretroviral (ARV) concentrations. ARV concentrations in tissues must be adequate to suppress HIV at the sites of action. While therapeutic drug monitoring in the plasma is well-known, drug monitoring in the tissues provides local assessments of adequate ARV exposure to prevent localized HIV resistance formation. Towards these efforts, we validated an ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) method in human tissues (cervical, rectal, and vaginal tissues) for the simultaneous quantification of five ARVs: bictegravir, cabotegravir, dolutegravir, doravirine, and raltegravir. For this assay, protein precipitation with acetonitrile with stable, isotopically-labeled internal standards followed by supernatant pre-concentration was performed. Analyte separation was accomplished using a multistep UPLC gradient mixture of 0.1 % formic acid in water (A) and acetonitrile (B) with a Waters Cortecs T3 (2.1x100 mm) column. The assay was extensively validated as per the United States Food and Drug Administration Bioanalytical Method Validation Guidance over a clinically observed range (0.05-50 ng/mL) with superb linearity (R2 > 0.99 across all ARVs). The assay run time was 8.5 min. This analytical method achieves appropriate performance of trueness (85.5-107.4 %), repeatability, and precision (CV < 15 %). Our method will be employed for the therapeutic monitoring of guideline-recommended ARVs in human tissues for monitoring therapeutic efficacy in HIV treatment and prevention research efforts., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Sharon A. Riddler reports a relationship with Gilead Sciences Inc that includes: funding grants. Sharon A. Riddler reports a relationship with Merck & Co Inc that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Baloxavir marboxil (BXM) is a cap-dependent nucleic acid endonuclease inhibitor, which exerts its antiviral effects after being metabolized to its active form baloxavir acid (BXA). Ethylenediamine tetra-acetic acid (EDTA) and heparin are the two most used anticoagulants in clinical blood sample collection to estimate drug levels in plasma. However, compared to heparin plasma, there is a lack of clinical pharmacokinetic data of BXA using EDTA anticoagulant tubes for blood collection. In the present study, an efficient, rapid, and sensitive ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous quantification of BXM and its active metabolite BXA in human plasma with its isotopic baloxavir-d5 (BXA-d5) as internal standard (IS). Plasma samples (50 μL) were undergone using acetonitrile containing 0.1 % formic acid a precipitant. Chromatographic separation was achieved by a Waters XBridge®C8 (2.1 mm × 50 mm, 2.5 µm) column. The gradient mobile phase was 0.1 % formic acid in water (A, pH 2.8) and 0.1 % formic acid in acetonitrile (B) and delivered at a flow rate of 0.6 mL/min for 4.5 min. BXM and BXA were monitored using a positive electrospray triple quadrupole mass spectrometer (TRIPLE QUAD™ 6500+) via multiple reaction monitoring mode. The mass-to-charge ratios (m/z) were 572.2→247.0, 484.2→247.0 and 489.2→252.0 for BXM, BXA, and BXA-d5 (IS). Calibration curves exhibited excellent linearity in the range of 0.1-10 ng/mL for BXM (r 2 > 0.996), and 0.3-300 ng/mL for BXA (r 2 > 0.998). Within-run and between-run precisions in coefficients of variations were less than 11.62 % for BXM and less than 7.47 % for BXA, and accuracies in relative error were determined to be within -7.78 % to 5.70 % for BXM and -6.67 % to 8.56 % for BXA. Extraction recovery efficiency was 92.76 % for BXM, 95.32 % for BXA, and 99.26 % for BXA-d5, respectively. The matrix effect of BXM and BXA was in line with the requirements, where the relative deviation of the accuracy was less than 6.67 % and the precision was less than 6.69 %. The validated efficient and simple UHPLC-MS/MS method was successfully used in the pharmacokinetic study of BXM and BXA in healthy human volunteers with K 2 EDTA and heparin tubes for blood collection. EDTA might compete with BXA for chelating metal ions and thereby decrease the plasma ratio in whole blood, leading to approximately 50 % lower measurement of pharmacokinetic parameters as compared with those obtained from heparin plasma anticoagulant tubes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Carbamazepine (CBZ) is an antiseizure medication known to induce the expression of cytochrome P4503A metabolic enzymes. Here, we describe a man living with HIV who underwent several changes in the daily dose of CBZ, which resulted in different induction effects on darunavir trough concentrations., Methods: A 59-year-old man with HIV, successfully undergoing maintenance antiretroviral treatment with darunavir/cobicistat once daily (combined with raltegravir), was prescribed CBZ for recurrent trigeminal neuralgia. Over subsequent months, the patient underwent various changes in the doses (from 200 to 800 mg/d) and trough concentrations (from 3.6 to 18.0 mg/L) of CBZ, guided by clinical response to trigeminal neuralgia., Results: A highly significant inverse association was observed between darunavir trough concentration and both CBZ dose or trough concentration (coefficient of determination >0.75, P < 0.0001). Ultimately, the darunavir dose was increased to 600 mg twice daily with ritonavir and dolutegravir to ensure optimal antiretroviral coverage, anticipating potential further uptitration of CBZ doses., Conclusions: The impact of CBZ on boosted darunavir exposure seemed to be dose- and concentration-dependent. The management of such drug-drug interactions in daily practice was facilitated through therapeutic drug monitoring. This case underscores the importance of a multidisciplinary approach that incorporates both antiretroviral and nonantiretroviral comedications contributing to the optimal management of polypharmacy in individuals living with HIV., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: The purposes of this study were to explore the pharmacokinetics of perampanel (PER) in children with epilepsy, identify factors that contribute to pharmacokinetic variations among subjects, evaluate the connection between PER exposure and clinical outcome, and establish an evidence-based approach for tailoring individualized antiepileptic treatment in this specific population., Methods: In this prospective study, PER plasma concentrations and genetic information on metabolic enzymes were obtained from 194 patients younger than 18 years. The disposition kinetics of PER in pediatric patients following oral dosing were characterized using nonlinear mixed effect models. The effective range for the plasma concentration of PER was determined by assessing the efficacy and safety of PER treatment and analyzing the relationship between drug exposure and clinical response. Monte Carlo simulations were then performed to evaluate and optimize the current dosing regimens., Results: The pharmacokinetic profile of PER was adequately described by a one-compartment model with first-order absorption and elimination. Body weight, total bilirubin level, and concomitant oxcarbazepine were found to have significant influences on PER pharmacokinetics. Model estimates of apparent clearance and volume of distribution were .016 ± .009 L/h/kg and 1.47 ± .78 L/kg, respectively. The effective range predicted from plasma concentration data in responders was 215-862 μg/L. Dosing scenarios stratified according to essential covariates were proposed through simulation analysis., Significance: In this study, we captured the pharmacokinetic/pharmacodynamic characteristics of PER in pediatric epilepsy patients through analysis of real-world data and adopted a pharmacometric approach to support an individualized dosing strategy for PER in this specific population., (© 2024 International League Against Epilepsy.)

Perampanel (PER) is a new type of antiseizure medication used for partial or generalized seizures. However, the plasma concentration shows obvious individual variability in children. The present study aims to ascertain the effect of age, comedications, and cytochrome P450 (CYP) 3A4/5 polymorphisms on PER exposure in Chinese pediatric patients with epilepsy. Clinical data were retrospectively collected in a tertiary children's hospital medical records system from January 2021 to December 2022. The influence factors on the daily dose, plasma concentration, and concentration-to-dose ratio (CDR) of PER were investigated. A total of 135 pediatric patients with 178 blood samples were involved. With a median daily dose of 4.0 mg (interquartile range, 3.0-5.0 mg), the median plasma concentration was 409.4 ng/mL (interquartile range, 251.7-639.4 ng/mL). The CDR in patients aged less than 4 years was significantly decreased by 48.0% and 39.1% compared with those aged 4-11 years and 12 years or older, respectively. Enzyme inducers significantly decreased the CDR of PER by 34.5%, while valproic acid showed an increase of 71.7%. In addition, genotype CYP3A5*3/*3 carriers presented a significant increase of 21.5% compared to the CYP3A5*1/*3 expresser. No correlations were observed between the CDR and CYP3A4∗1G polymorphism. PER showed high variations in individual plasma concentrations. Age younger than 4 years, comedication with enzyme inducers or valproic acid, and possession of the CYP3A5*3 genotype potentially predicted PER exposure in pediatric patients with epilepsy., (© 2024, The American College of Clinical Pharmacology.)

Background: Routine monitoring of direct oral anticoagulant (DOAC) levels is not recommended but may be useful in certain clinical situations. There is a knowledge gap regarding the clinical use of DOAC levels in Australian hospitals., Aims: To evaluate the clinical settings, indications and changes to anticoagulant management associated with DOAC levels in a tertiary hospital in Northern Tasmania, Australia., Methods: Patients with one or more DOAC levels (dabigatran, rivaroxaban or apixaban) requested between January 2017 and December 2022 were identified. Retrospective chart review was performed to evaluate the clinical settings, indications, adequacy of request information and changes to clinical management associated with the measurement of DOAC levels., Results: One hundred and twenty-nine DOAC measurements (54 rivaroxaban, 66 apixaban and nine dabigatran) were performed in 98 patients between January 2017 and December 2022. Annual requests for DOAC levels increased significantly between 2017 and 2019 and remained stable between 2020 and 2021 but declined in 2022. Overall, the most common indication for a DOAC level was renal impairment, followed by bleeding and recurrent thrombosis. Approximately 25% of requests were for acute bleeding with a reversal/haemostatic agent given in 45% of patients, while 10% were prior to urgent surgery. Measurement of DOAC levels was associated with a change in management in 50% of cases. 10% of requests did not specify anticoagulant history., Conclusion: Trends in requests for DOAC levels have changed over time. Clinician education regarding the importance of providing specific anticoagulant history is essential. Future prospective studies investigating the clinical utility of DOAC levels in different clinical settings are needed., (© 2024 Royal Australasian College of Physicians.)

Contezolid is a novel oxazolidinone antibiotic with good antibacterial activity against gram-positive bacteria including methicillin-resistant Staphylococcus aureus. For the purpose to further characterize the pharmacokinetics of contezolid and its major metabolite M2, accurate and rapid ultra-performance liquid chromatography-tandem mass spectrometric assays (UPLC-MS/MS) were developed and validated for simultaneous quantification of contezolid and M2 in human plasma and urine. The plasma samples were pretreated by liquid-liquid extraction. The automated solid phase extraction method was used to preprocess urine samples. ACQUITY UPLC® BEH C8 (2.1 mm × 100 mm, 1.7 µm) column was used to separate the analytes with a gradient mobile phase of acetonitrile and water at a flow rate of 0.4 mL/min. The calibration curves showed good linearity over the concentration ranges of 0.0100-5.00 µg/mL for contezolid in plasma and urine, 0.00200-1.00 µg/mL in plasma and 0.0200-10.0 µg/mL in urine for M2, respectively. For both plasma and urine assays, the intra- and inter-batch accuracy and precision were within 15% for all quality control levels, including the lower limit of quantitation. The methods were fully validated and successfully applied to a pharmacokinetic study of contezolid tablets in subjects with moderate hepatic impairment., (Copyright © 2022. Published by Elsevier B.V.)

AMPK is an energy sensor modulating metabolism, inflammation, and a target for metabolic disorders. Metabolic dysfunction results in lower AMPK activity. PXL770 is a direct AMPK activator, inhibiting de novo lipogenesis (DNL) and producing efficacy in preclinical models. We aimed to assess pharmacokinetics, safety, and pharmacodynamics of PXL770 in humans with metabolic syndrome-associated fatty liver disease. In a randomized, double-blind four-week trial, 12 overweight/obese patients with non-alcoholic fatty liver disease (NAFLD) and insulin resistance received PXL770 500 mg QD; 4 subjects received matching placebo. Endpoints included pharmacokinetics, hepatic fractional DNL, oral glucose tolerance testing, additional pharmacodynamic parameters, and safety. PK parameters show adequate plasma exposure in NAFLD patients for daily oral dosing. PXL770 decreases DNL-both peak and AUC are reduced versus baseline-and improves glycemic parameters and indices of insulin sensitivity versus baseline. Assessment of specific lipids reveals decrease in diacyglycerols/triacylglycerols. Safety/tolerability are similar to placebo. These results unveil initial human translation of AMPK activation and support this therapeutic strategy for metabolic disorders., Competing Interests: C.C., D.E.M., F.M, J.D., P.G.-D., P.F., P.T., S.B., and S.H.-B. are employees of Poxel SA and have received stock options as a condition of employment. K.C. has served as a consultant for Allergan, Altimmune, Arrowhead, AstraZeneca, BMS, Boehringer Ingelheim, Coherus, Eli Lilly, Fractyl, Hanmi, Genentech, Gilead, Intercept, Janssen, Pfizer, Poxel, Prosciento, Madrigal, and Novo Nordisk. The study was funded and designed by the sponsor (Poxel SA) with the support of expert consultants in the NASH field. The corresponding author, all co-authors, and the sponsor had full responsibility for the decision to submit for publication. Patents WO2011080277A1 and WO2020099678A1, owned by Poxel SA, are related to this work., (© 2021 Poxel SA.)

Background: Phase 3 clinical studies showed non-inferiority of long-acting intramuscular cabotegravir and rilpivirine dosed every 4 weeks to oral antiretroviral therapy. Important phase 2 results of every 8 weeks dosing, and supportive modelling, underpin further evaluation of every 8 weeks dosing in this trial, which has the potential to offer greater convenience. Our objective was to compare the week 48 antiviral efficacy of cabotegravir plus rilpivirine long-acting dosed every 8 weeks with that of every 4 weeks dosing., Methods: ATLAS-2M is an ongoing, randomised, multicentre (13 countries; Australia, Argentina, Canada, France, Germany, Italy, Mexico, Russia, South Africa, South Korea, Spain, Sweden, and the USA), open-label, phase 3b, non-inferiority study of cabotegravir plus rilpivirine long-acting maintenance therapy administered intramuscularly every 8 weeks (cabotegravir 600 mg plus rilpivirine 900 mg) or every 4 weeks (cabotegravir 400 mg plus rilpivirine 600 mg) to treatment-experienced adults living with HIV-1. Eligible newly recruited individuals must have received an uninterrupted first or second oral standard-of-care regimen for at least 6 months without virological failure and be aged 18 years or older. Eligible participants from the ATLAS trial, from both the oral standard-of-care and long-acting groups, must have completed the 52-week comparative phase with an ATLAS-2M screening plasma HIV-1 RNA less than 50 copies per mL. Participants were randomly assigned 1:1 to receive cabotegravir plus rilpivirine long-acting every 8 weeks or every 4 weeks. The randomisation schedule was generated by means of the GlaxoSmithKline validated randomisation software RANDALL NG. The primary endpoint at week 48 was HIV-1 RNA ≥50 copies per mL (Snapshot, intention-to-treat exposed), with a non-inferiority margin of 4%. The trial is registered at ClinicalTrials.gov, NCT03299049 and is ongoing., Findings: Screening occurred between Oct 27, 2017, and May 31, 2018. Of 1149 individuals screened, 1045 participants were randomised to the every 8 weeks (n=522) or every 4 weeks (n=523) groups; 37% (n=391) transitioned from every 4 weeks cabotegravir plus rilpivirine long-acting in ATLAS. Median participant age was 42 years (IQR 34-50); 27% (n=280) female at birth; 73% (n=763) white race. Cabotegravir plus rilpivirine long-acting every 8 weeks was non-inferior to dosing every 4 weeks (HIV-1 RNA ≥50 copies per mL; 2% vs 1%) with an adjusted treatment difference of 0·8 (95% CI -0·6-2·2). There were eight (2%, every 8 weeks group) and two (<1%, every 4 weeks group) confirmed virological failures (two sequential measures ≥200 copies per mL). For the every 8 weeks group, five (63%) of eight had archived non-nucleoside reverse transcriptase inhibitor resistance-associated mutations to rilpivirine at baseline. The safety profile was similar between dosing groups, with 844 (81%) of 1045 participants having adverse events (excluding injection site reactions); no treatment-related deaths occurred., Interpretation: The efficacy and safety profiles of dosing every 8 weeks and dosing every 4 weeks were similar. These results support the use of cabotegravir plus rilpivirine long-acting administered every 2 months as a therapeutic option for people living with HIV-1., Funding: ViiV Healthcare and Janssen., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Bictegravir coformulated with emtricitabine and tenofovir alafenamide as a fixed-dose combination (BIC/FTC/TAF 50/200/25 mg) is recommended as an initial regimen in patients who are antiretroviral (ARV)-naïve or virologically suppressed on a stable ARV regimen. However, no real-world pharmacokinetic (PK) data are available in treatment-experienced patients with antiretroviral resistance receiving BIC/FTC/TAF plus a boosted protease inhibitor., Setting/methods: This prospective, single-center, nonrandomized pharmacokinetic study enrolled adult treatment-experienced persons with HIV and creatinine clearance >30 mL/min receiving BIC/FTC/TAF + DRV/c as part of routine clinical care. Steady-state PK profiles of BIC, TAF, tenofovir (TFV), and DRV after daily dosing of BIC/FTC/TAF + darunavir/cobicistat (DRV/c) were obtained with samples at predose and 0.5, 1, 2, and 4 hours postdose. The AUC0-24 at steady state was extrapolated by imputing C0 for C24 for each participant (AUC0-tau,exp)., Results: Nine participants were enrolled with a median age of 59 years (range 54-67) and median number of years on ART of 19 (range 5.8-30). The median (interquartile range [IQR]) BIC AUC0-tau,exp and Cmax values were 128.9 µg*h/mL (78.1-159.5) and 6.9 µg/mL (5.1-9.8), respectively. The median (IQR) TAF AUC0-tau,exp and Cmax values were 0.376 µg*h/mL (0.199-0.430) and 0.276 µg/mL (0.149-0.543), respectively. Predose concentrations of TFV and DRV were comparable with historical data., Conclusion: Treatment-experienced persons with HIV receiving BIC/FTC/TAF + darunavir/cobicistat (DRV/c) had BIC exposures (AUC0-tau) that were increased by approximately 26% compared with historical PK data. Although TAF exposures were substantially increased, plasma TFV was only modestly higher. These results suggest that BIC/TAF/FTC + DRV/c is a viable antiviral regimen option for treatment-experienced persons., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

It is unclear whether elderly patients established on direct oral anticoagulants (DOACs) have greater exposure to these drugs, which could subsequently increase their risk of bleeding. We assessed DOAC exposure and factors affecting it in a real-world elderly cohort of patients. For this, 151 medically stable hospital inpatients (76 established on apixaban, 61 on rivaroxaban, 14 on dabigatran) with a median [interquartile range (IQR)] age of 84 (78-89) years were recruited. Patients provided blood samples for measurement of peak and trough plasma DOAC concentrations. There was up to 48-fold and 13-fold variation in trough and peak plasma drug concentrations respectively. A significantly greater proportion of patients on apixaban had peak plasma drug concentrations within the reported ranges compared to those on either rivaroxaban or dabigatran (82·9% vs. 44·3% vs. 64·3% respectively; P < 0·001). A third of the variability in DOAC plasma concentrations was attributed to the influences of DOAC dosage, renal function and gender. To what extent the observed increases in DOAC exposure in the older patients is the cause of their increased risk of bleeding, which could potentially be ameliorated by dosing titration, requires further investigation., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Abstract: Direct-acting oral anticoagulants (DOACs) vary in bioavailability and sites of absorption in the gastrointestinal tract (GIT). Data on DOAC use after major GIT surgery are limited. The aim of this case series was to report the impact of surgical resection or bypass of the GIT on rivaroxaban and apixaban peak plasma concentrations. This was a case series of patients who received rivaroxaban or apixaban after GIT surgery, during the period of July 1, 2019, to December 31, 2020. Peak plasma concentrations of rivaroxaban and apixaban were assessed for the expected concentrations. Of the 27 assessed patients, 18 (66.7%) received rivaroxaban, and 9 (33.3%) received apixaban. After rivaroxaban therapy, 4 of 5 patients (80%) who underwent gastrectomy, and 3 of 3 patients (100%) who underwent duodenum and proximal jejunum exclusion had peak plasma concentrations of rivaroxaban lower than the effective range, whereas 11 of 11 patients (100%) who underwent distal bowel or ileostomy had peak rivaroxaban plasma within the effective range. After apixaban therapy, 5 of 6 patients (83.3%) who underwent total or partial gastrectomy achieved effective peak concentrations. All the patients who underwent proximal and distal bowel resection or bypass had peak concentrations of apixaban within the effective range. In conclusion, surgical resection or bypass of the upper GIT could affect DOAC absorption and subsequently peak plasma concentrations. This effect was more observed among rivaroxaban recipients. An injectable anticoagulant or vitamin K antagonist may be preferred if DOAC concentrations cannot be measured after GIT surgery., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

In this study, we evaluated the in vitro stability of direct oral anticoagulants (DOACs) in blood samples of 57 patients under different storage conditions using functional coagulation assays. We determined the analyte concentrations (1) immediately after blood collection (baseline); (2) after storage of citrated whole blood (agitated) at room temperature and citrated plasma at room temperature and at 4 °C for 4, 8, and 24 h, respectively; and (3) after storage of citrated plasma at -20 °C for 30, 60, and 90 days. According to the concept of acceptable change limits (ACL), analytes were considered stable if the mean relative analyte recovery at a given time was >78%. The mean baseline values (range) of dabigatran, rivaroxaban, apixaban, and edoxaban were 115 ng/mL (62-217), 129 ng/mL (31-215), 156 ng/mL (49-362), and 101 ng/mL (33-283), respectively. After applying the analyte stability limit, all four DOACs were stable for 24 h at room temperature and at 4 °C. The mean recovery after 24 h was 102-111% for dabigatran, 88-97% for rivaroxaban, 95-98% for apixaban, and 90-96% for edoxaban. When plasma samples were stored at -20 °C, the mean percentage deviation after 90 days for all four DOACs was ≤10%, even after three freeze-thaw cycles. Thus, for the correct determination of DOAC plasma concentrations, blood samples do not have to be analyzed immediately and can be stored at room temperature for up to 24 h before analysis. In clinical practice, blood sample transport and storage for DOAC measurements appear to be unproblematic.

Objective: To compare the advanced glycation end products (AGEs) levels in follicular fluid according to the different ovarian responses of women who underwent controlled ovarian stimulation due to unexplained infertility and to examine the relationship between these levels and pregnancy outcomes., Methods: Sixty-three women who underwent fresh IVF/ICSI cycles with GNRH antagonist protocol were divided into 3 groups according to the number of retrieved oocytes as suboptimal (4-9 oocytes), optimal (10-15 oocytes) and high (>15 oocytes) responders. AGEs levels in follicular fluid were measured by ELISA method., Results: AGEs levels were 6.81 ± 2.20 µg/ml, 5.30 ± 2.01 and 6.44 ± 1.43 µg/ml in suboptimal, optimal and high response group, respectively. AGEs level was significantly higher in suboptimal response group than in optimal response group. The cutoff level of 6.19 µg/ml had a sensitivity of 59.3% and a specificity of 66.7% in distinguishing the suboptimal response group from the optimal response group. However, there were no statistically significant difference between AGEs levels and clinical pregnancy and live birth rates., Conclusion: Increased AGEs level in follicular fluid may be associated with decreased ovarian response during controlled ovarian stimulation in unexplained infertility case, however, it does not provide information about pregnancy outcomes.

Introduction/aims: Cortical hyperexcitability is a feature of amyotrophic lateral sclerosis (ALS) and cortical excitability can be measured using transcranial magnetic stimulation (TMS). Resting motor threshold (MT) is a measure of cortical excitability, largely driven by glutamate. Perampanel, a glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor blocker, is predicted to increase the cortical excitability threshold. This study aimed to evaluate TMS to functionally assess target engagement in a study of perampanel in ALS., Method: We studied the MT of ALS patients randomized to a single dose of perampanel or placebo 5:1 hourly for 4 h. Twelve patients participated at 4 mg and 7 returned for dosing and retesting at 8 mg. The study was terminated in April 2020 due to coronavirus disease 2019-related restrictions, after 7 out of 12 planned patients had received the 8 mg dose. Serum concentrations were also measured., Results: Ten patients received the 4 mg dose (2 received placebo) and 5 received the 8 mg dose (2 received placebo). Motor Threshold increased at 2 h after dosing in the combined treatment group +7% of maximal stimulator output (P < .01). Change could be detected in the larger 4 mg group (P = .02), but not in the smaller 8 mg dose group (P = .1). No side effects were reported after single dose exposure., Discussion: This study shows that perampanel effects the physiology of upper motor neurons. Studies aiming at gauging the effect of perampanel on ALS disease progression are already ongoing. Motor threshold may serve as a marker of biological target engagement., (© 2021 Wiley Periodicals LLC.)

Introduction: ST Genesia is a new automated system enabling quantitative standardized evaluation of thrombin generation (TG), for example, in patients receiving anti-Xa direct inhibitors (xabans). Data on its analytical performances are scarce., Methods: Over an 18-month period, repeatability, reproducibility, and accuracy were assessed using STG-ThromboScreen (without or with thrombomodulin) or STG-DrugScreen reagents (corresponding to intermediate/high tissue-factor concentration, respectively), and controls. Furthermore, reproducibility was assessed using commercialized lyophilized and frozen normal pooled plasmas. Rivaroxaban and apixaban impacts on TG parameters were assessed using spiking experiments. Finally, a comparison with the Calibrated Automated Thrombogram method (CAT) (PPP reagent) was performed using plasma from healthy volunteers enrolled in the DRIVING-studyNCT01627665) before and after rivaroxaban intake., Results: For all dedicated quality control (QC) levels, inter-series coefficients of variations (CV) were <7% for temporal TG parameters, peak height (PH), and endogenous thrombin potential (ETP), whether results were normalized with a dedicated reference plasma STG-RefPlasma or not. Noteworthy, STG-RefPlasma used for normalization displayed substantially high PH and ETP. Mean biases between the observed and manufacturer's assigned QC values were mostly <7%. Both rivaroxaban/apixaban plasma concentrations were significantly associated with TG parameters. Finally, Bland-Altman plots showed a good agreement between ST Genesia-STG-ThromboScreen and CAT method within the explored range of values, although biases could be observed (PH: 16.4 ± 13.2%, ETP: 17.8 ± 11.9%)., Conclusion: ST Genesia ® enables the reliable measurement of TG parameters in both in vitro and ex vivo xaban plasma samples using either STG-ThromboScreen or STG-DrugScreen according to xaban concentrations. The use of reference plasma, despite not completely reflecting a normal pooled plasma behavior, likely improves standardization and inter-laboratory comparisons., (© 2020 John Wiley & Sons Ltd.)

In some clinical situations, measurements of anticoagulant effect of apixaban may be needed. We investigated the inter- and intra-individual apixaban variability in patients with atrial fibrillation and correlated these results with clinical outcome. We included 62 patients receiving either 5 mg (A5, n = 32) or 2.5 mg (A2.5, n = 30) apixaban twice-daily. We collected three trough and three peak blood samples 6-8 weeks apart. Apixaban concentration was measured by liquid chromatography-tandem mass-spectrometry (LC-MS/MS) and by anti-Xa. Patients on A2.5 were older, had lower creatinine clearance, higher CHA 2 DS 2 VASc (4.7 ± 1.0 vs. 3.4 ± 1.7) and lower trough (85 ± 39 vs. 117 ± 53 ng/mL) and peak (170 ± 56 vs. 256 ± 91 ng/mL) apixaban concentrations than patients on A5 (all p < 0.01). In patients on A5, LC-MS/MS showed a significant difference between through levels and between peak levels (p < 0.01). During apixaban treatment, 21 patients suffered bleeding (2 major). There was no association between bleeding and apixaban concentrations or variability. Four patients who suffered thromboembolic event had lower peak apixaban concentrations than patients without it (159 ± 13 vs. 238 ± 88 ng/mL, p = 0.05). We concluded, that there was a significant intra- and inter-individual variability in apixaban trough and peak concentrations. Neither variability nor apixaban concentrations were associated with clinical outcomes.

Abstract: Patients with atrial fibrillation (AF) on long-term direct oral anticoagulants (DOACs) may be at higher risk of bleeding because of higher anti-Xa or anti-IIa levels. However, there is no postmarketing study investigating these DOAC plasma levels at the time of bleeding. The aim of this study was to evaluate DOAC levels at the time of a bleeding emergency. We analyzed 5440 patients examined at our Emergency Department in from April 1, 2019, to September 30, 2019. During this period, we prospective identified 105 consecutive patients with bleeding while on long-term antithrombotic therapy; 49 patients had AF on DOACs. We compared DOAC levels in patients who bled against a control sample of 55 patients who tolerated long-term high dose DOAC therapy without any emergency. Samples of these patients were tested with drug-specific anti-Xa chromogenic analysis (rivaroxaban and apixaban) and with Hemoclot Thrombin Inhibitor assay (dabigatran). Dabigatran-treated patients who bled had significantly higher anti-IIa levels when compared with trough (261.4 ± 163.7 vs. 85.4 ± 57.2 ng/mL, P < 0.001) and peak samples of controls (261.4 ± 163.7 vs. 138.8 ± 78.7 ng/mL, P < 0.05). Similarly, there were significantly higher anti-Xa levels in rivaroxaban-treated and apixaban-treated patients with bleeding compared with trough control samples (rivaroxaban: 245.9 ± 150.2 vs. 52.5 ± 36.4 ng/mL, P <0.001 and apixaban: 311.8 ± 142.5 vs. 119.9 ± 81.7 ng/mL, P < 0.001), as well as in apixaban-treated patients when compared with peak control samples (311.8 ± 142.5 vs. 210.9 ± 88.7 ng/mL, P < 0.05). Finally, rivaroxaban anti-Xa levels in patients who bled tended to be higher compared with peak control samples (245.9 ± 150.2 vs. 177.6 ± 38.6 ng/mL, P = 0.13). This observational study showed a significant difference in anti-IIa and anti-Xa plasma levels in patients with AF with bleeding complications compared with those who tolerated long-term high-dose DOAC therapy without bleeding complications., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background and Objectives: Islatravir (MK-8591) is a novel nucleoside analogue in development for the treatment and prevention of HIV-1 infection. Doravirine is a non-nucleoside reverse transcriptase inhibitor indicated for the treatment of HIV-1 infection. This study evaluated the pharmacokinetics, safety, and tolerability of islatravir and doravirine coadministration in a double-blind, placebo-controlled, randomized, fixed-sequence study., Methods: Adult participants without HIV infection were administered oral doravirine 100 mg (n = 10) or placebo (n = 4) once daily (QD) for 5 days, immediately followed by oral islatravir 2.25 mg (n = 10) or placebo QD (n = 4) for 14 days; islatravir 2.25 mg and doravirine 100 mg QD, or placebo QD, were then coadministered for 5 days. Pharmacokinetic and safety data were collected., Results: Doravirine geometric least-squares mean ratios (90% confidence intervals (CIs)) of (doravirine + islatravir)/doravirine for the area under the plasma drug concentration-time curve over 24 h (AUC 0-24h ), maximum plasma concentration (C max ), and plasma concentration at 24 h post-dose (C 24h ) were not meaningfully impacted. Islatravir geometric least-squares mean ratios (90% CI) of (islatravir + doravirine)/islatravir for AUC 0-24h and C max were both close to unity, 1.06 (1.01, 1.12) and 1.08 (0.91, 1.27), respectively. All study regimens were generally well tolerated., Conclusion: These results indicate that coadministration of islatravir and doravirine had no clinically meaningful effect on the pharmacokinetics of either drug, and support further clinical investigation of islatravir in combination with doravirine for the treatment of HIV-1 infection.

A once every eight-week cabotegravir (CAB) long-acting parenteral is more effective than daily oral emtricitabine and tenofovir disoproxil fumarate in preventing human immunodeficiency virus type one (HIV-1) transmission. Extending CAB dosing to a yearly injectable advances efforts for the elimination of viral transmission. Here we report rigor, reproducibility and mechanistic insights for a year-long CAB injectable. Pharmacokinetic (PK) profiles of this nanoformulated CAB prodrug (NM2CAB) are affirmed at three independent research laboratories. PK profiles in mice and rats show plasma CAB levels at or above the protein-adjusted 90% inhibitory concentration for a year after a single dose. Sustained native and prodrug concentrations are at the muscle injection site and in lymphoid tissues. The results parallel NM2CAB uptake and retention in human macrophages. NM2CAB nanocrystals are stable in blood and tissue homogenates. The long apparent drug half-life follows pH-dependent prodrug hydrolysis upon slow prodrug nanocrystal dissolution and absorption. In contrast, solubilized prodrug is hydrolyzed in hours in plasma and tissues from multiple mammalian species. No toxicities are observed in animals. These results affirm the pharmacological properties and extended apparent half-life for a nanoformulated CAB prodrug. The report serves to support the mechanistic design for drug formulation safety, rigor and reproducibility.

Dolutegravir (DTG) is an integrase inhibitor, whose gastrointestinal absorption is impaired by the formation of chelates with multivalent metal cation preparations. However, little is known regarding the interactions of DTG with preparations containing other multivalent metal cations or with polycation polymer preparations. This study examined how the pharmacokinetics of DTG are affected by co-administration with Al(OH) 3 , LaCO 3 , and the polycation polymers bixalomer (Bxl) and sevelamer (Svl). Prior to oral administration of DTG (5 mg/kg), rats were orally administered Al(OH) 3 (150 or 300 mg/kg), LaCO 3 (50 or 75 mg/kg), Bxl (250 or 500 mg/kg), or Svl (300 or 600 mg/kg). Serum concentrations of DTG were then measured over the next 24 h. Compared to the administration of DTG alone, its co-administration with Al(OH) 3 , LaCO 3 , Bxl, and Svl led to reduced serum concentration of DTG, and consequently, a significantly reduced area under the curve. These comparisons also revealed a considerable reduction in the maximum concentration, suggesting that the interactions of these agents with DTG in the intestinal tract inhibit absorption of DTG. The above results demonstrate that Al(OH) 3 , LaCO 3 , Bxl, and Svl affect the pharmacokinetics of DTG and indicate the need for caution when combining any of the above preparations with DTG., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2020 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.)

Background: Despite their usefulness in perioperative and acute care settings, factor-Xa inhibitor-specific assays are scarcely available, contrary to heparin anti-Xa assay. We assessed whether the heparin anti-Xa assay can (1) be used as a screening test to rule out apixaban, rivaroxaban, fondaparinux, and danaparoid levels that contraindicate invasive procedures according to current guidelines (>30 ng·mL-1, >30 ng·mL-1, >0.1 µg·mL-1, and >0.1 IU·mL-1, respectively), (2) quantify the anticoagulant level if found significant, that is, if it exceeded the abovementioned threshold., Methods: In the derivation cohort then in the validation cohort, via receiver operating characteristics (ROC) curve analysis, we evaluated the ability of heparin anti-Xa assay to detect levels of factor-Xa inhibitors above or below the abovementioned safety thresholds recommended for an invasive procedure (screening test). Among samples with relevant levels of factor-Xa inhibitor, we determined the conversion factor linking the measured level and heparin anti-Xa activity in a derivation cohort. In a validation cohort, the estimated level of each factor-Xa inhibitor was thus inferred from heparin anti-Xa activity. The agreement between measured and estimated levels of factor-Xa inhibitors was assessed., Results: Among 989 (355 patients) and 756 blood samples (420 patients) in the derivation and validation cohort, there was a strong linear relationship between heparin anti-Xa activities and factor-Xa inhibitors measured level (r = 0.99 [95% confidence interval {CI}, 0.99-0.99]). In the derivation cohort, heparin anti-Xa activity ≤0.2, ≤0.3, <0.1, <0.1 IU·mL-1 reliably ruled out a relevant level of apixaban, rivaroxaban, fondaparinux, and danaparoid, respectively (area under the ROC curve ≥0.99). In the validation cohort, these cutoffs yielded excellent classification accuracy (≥96%). If this screening test indicated relevant level of factor-Xa inhibitor, estimated and measured levels closely agreed (Lin's correlation coefficient close to its maximal value: 95% CI, 0.99-0.99). More than 96% of the estimated levels fell into the predefined range of acceptability (ie, 80%-120% of the measured level)., Conclusions: A unique simple test already widely used to assay heparin was also useful for quantifying these 4 other anticoagulants. Both clinical and economic impacts of these findings should be assessed in a specific study., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 International Anesthesia Research Society.)

Therapeutic drug monitoring (TDM) is used in certain clinically selected cases and in research settings to optimize the response to antiretroviral therapy. Plasma of blood is commonly used for TDM, but blood sampling is invasive and at risk for transmission of infectious agents. On the other hand, saliva sampling is noninvasive, safe, cheap, and easily performed compared to blood. Dolutegravir (DTG) is now widely prescribed as a key component of antiretroviral therapy for HIV infection. In this study, we examined the relationship between DTG concentrations in plasma and saliva of treated patients to explore the possibility of using saliva as an alternative body fluid of TDM. A total of 17 pairs of blood and saliva samples were obtained from 15 consented HIV-1-infected subjects treated with DTG containing regimens for more than one month. Both blood and saliva samples were collected within 1 h of each other. Drug concentrations were determined by liquid chromatography-tandem mass spectrometry using DTG-d5 as an internal standard. The LLOQ was 0.5 ng/mL. The calibration curves were prepared with pooled plasma or saliva containing DTG in a range of 0.5-100 ng/mL with precision of <14.4% and accuracy within ±14.7%. The DTG concentrations in the plasma and saliva were significantly correlated (Pearson's correlation coefficient r = 0.76, p < 0.001). The median ratio of the drug concentration in saliva to those in plasma was 0.0056, which is close to the rate of non-protein-bound DTG in plasma (0.70%), suggesting that only free DTG in plasma is transported to the salivary glands and secreted into saliva. The present study demonstrates that DTG concentration in saliva reflects the pharmacologically active drug concentration in plasma and may provide an easily accessible alternative for monitoring effective antiretroviral treatment., Competing Interests: The authors have read the journal’s policy and declare the following competing interests: KS and SK are employees of Hanah Meditech Co. Ltd. However, this company was established after this study concluded, and KS and SK were employees of Keio University, Tokyo, Japan at the time the study was conducted. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Objective: To report a near-fatal poisoning after intentional injection of ricin from a castor bean ( Ricinus communis ) extract., Case Report: A 21 year-old man self-injected ∼3 mL of a castor bean extract intramuscularly and subcutaneously in the left antecubital fossa. Upon admission to our ED (1 h post-exposure; day 1, D1) he was awake and alert, but complained of mild local pain and showed slight local edema and erythema. He evolved to refractory shock (∼24 h post-exposure) that required the administration of a large volume of fluids and high doses of norepinephrine and vasopressin, mainly from D2 to D4. During this period, he developed clinical and laboratory features compatible with systemic inflammatory response syndrome, multiple organ dysfunction, capillary leak syndrome, rhabdomyolysis, necrotizing fasciitis and possible compartment syndrome. The patient underwent forearm fasciotomy on D4 and there was progressive improvement of the hemodynamic status from D7 onwards. Wound management involved several debridements, broad-spectrum antibiotics and two skin grafts. Major laboratory findings within 12 days post-exposure revealed hypoalbuminemia, proteinuria, thrombocytopenia, leukocytosis and increases in cytokines (IL-6, IL-10 and TNF-α), troponin and creatine kinase. Ricin A-chain (ELISA) was detected in serum up to D3 (peak at 24 h post-exposure), with ∼79% being excreted in the urine within 64 h post-exposure. Ricinine was detected in serum and urine by LC-MS up to D5. A ricin A-chain concentration of 246 µg/mL was found in the seed extract, corresponding to the injection of ∼738 µg of ricin A-chain (∼10.5 µg/kg). The patient was discharged on D71, with limited range of motion and function of the left forearm and hand., Conclusion: Ricin injection resulted in a near-fatal poisoning that evolved with septic shock-like syndrome, multiple organ dysfunction and necrotizing fasciitis, all of which were successfully treated with supportive care.

Background: Effective antiviral drugs for COVID-19 are still lacking. This study aims to evaluate the clinical outcomes and plasma concentrations of baloxavir acid and favipiravir in COVID-19 patients., Methods: Favipiravir and baloxavir acid were evaluated for their antiviral activity against SARS-CoV-2 in vitro before the trial initiation. We conducted an exploratory trial with 3 arms involving hospitalized adult patients with COVID-19. Patients were randomized assigned in a 1:1:1 ratio into baloxavir marboxil group, favipiravir group, and control group. The primary outcome was the percentage of subjects with viral negative by Day 14 and the time from randomization to clinical improvement. Virus load reduction, blood drug concentration and clinical presentation were also observed. The trial was registered with Chinese Clinical Trial Registry (ChiCTR 2000029544)., Results: Baloxavir acid showed antiviral activity in vitro with the half-maximal effective concentration (EC 50 ) of 5.48 μM comparable to arbidol and lopinavir, but favipiravir didn't demonstrate significant antiviral activity up to 100 μM. Thirty patients were enrolled. The percentage of patients who turned viral negative after 14-day treatment was 70%, 77%, and 100% in the baloxavir marboxil, favipiravir, and control group respectively, with the medians of time from randomization to clinical improvement was 14, 14 and 15 days, respectively. One reason for the lack of virological effect and clinical benefits may be due to insufficient concentrations of these drugs relative to their antiviral activities. One of the limitations of this study is the time from symptom onset to randomization, especially in the baloxavir marboxil and control groups, which is higher than the favipiravir group., Conclusions: Our findings could not prove a benefit of addition of either baloxavir marboxil or favipiravir under the trial dosages to the existing standard treatment., (Copyright © 2020. Published by Elsevier B.V.)

With an elimination half-life of 105 hours, perampanel (PER) allows a once-daily dosing regimen. In pivotal trials, when PER was tapered, it was therefore usually discontinued abruptly. Thus, in our hospital we have always practiced abrupt cessation. In this case series, we investigated how long PER serum concentrations still remain measurable after abrupt discontinuation of PER and whether withdrawal symptoms, such as an increase in seizures or status epilepticus, occur. PER serum levels and the clinical course of 15 adult in-patients were monitored for three weeks based on a retrospective study design following abrupt discontinuation of PER. After one week, PER was still detected in 13 of 15 patients, after two weeks in 10, and after three weeks in three. Neither a severe increase in seizure frequency nor status epilepticus occurred. However, modifications of the concomitant antiseizure drugs were necessary. The abrupt discontinuation of PER leads to a slow decrease in plasma concentration, thus resembling self-evident gradual discontinuation of PER. In some cases, PER may still be measurable and thus clinically active even weeks after its discontinuation. Efficacy and safety of other antiseizure drugs can be estimated appropriately only thereafter.

Perampanel is a third-generation antiepileptic drug (AED), while lamotrigine is a second-generation AED. Both drugs are subject to extensive pharmacokinetic variability between different patients. Furthermore, it has been reported that perampanel and lamotrigine may be implied in pharmacokinetic drug-drug interactions with other AEDs such as carbamazepine or valproate, with consequent alterations of plasma concentrations. This emphasizes the relevance of therapeutic drug monitoring of perampanel and lamotrigine with appropriate bioanalytical methods. Herein, the development and validation of a bioanalytical techique for the simultaneous quantification of perampanel and lamotrigine in human plasma samples is described. The reported method is based on high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD) and sample preparation consists of liquid-liquid extraction. Chromatographic separation of the analytes (lamotrigine and perampanel) and the internal standard (entacapone) was achieved in 12 min on a reversed-phase C 18 column at 40 °C by applying a gradient elution program with a mobile phase composed of 0.1% ortho-phosphoric acid pH 2.79 (A) and acetonitrile (B) pumped at 1.0 mL/min. Perampanel was quantified at 320 nm while lamotrigine and the internal standard were monitored at 306 nm. Calibration curves were linear in the concentration range of 0.03-4.5 µg/mL (r 2  = 0.9978) for perampanel and in the concentration range of 0.25-30 µg/mL (r 2  = 0.9981) for lamotrigine. Overall precision did not exceed 14.3% and accuracy ranged from -6.08 to 12.66%. Some drugs potentially co-prescribed with perampanel and lamotrigine were tested and did not interfere with the retention times of the analytes and internal standard. The method was then successfully applied for the quantification of perampanel and lamotrigine in plasma samples obtained from 42 drug-resistant epileptic patients admitted to the Coimbra University Hospital Centre (CHUC.EPE, Coimbra, Portugal). In conclusion, it is a suitable method for the therapeutic drug monitoring of lamotrigine and perampanel in drug-resistant epileptic patients, as well as, for the assessment of drug-drug interactions. It can also be adopted by hospitals and laboratories, when HPLC with fluorescence and mass spectrometry detections are unavailable., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: People living with human immunodeficiency virus are ageing under combination antiretroviral treatments but data on drug exposure in serum and cerebrospinal fluid are limited. Dolutegravir is a widely used second-generation integrase strand transfer inhibitor: conflicting data suggest that neuropsychiatric side effects may present at a higher frequency in patients with higher dolutegravir serum concentrations., Methods: We performed a retrospective analysis of our therapeutic drug monitoring registry identifying patients receiving once-daily dolutegravir without concomitant interacting drugs and significant clinical conditions. Data were analysed stratifying time after drug dose intake (maximum concentration 0.5-4 and trough concentration 21-27 h). Cerebrospinal fluid samples from patients enrolled in neurological studies and receiving dolutegravir were analysed for dolutegravir cerebrospinal fluid concentrations and cerebrospinal fluid-to-plasma ratios. Serum and cerebrospinal fluid concentrations were measured through validated chromatographic methods., Results: We included 207 (providing 457 serum samples) and 41 patients (providing 41 cerebrospinal fluid samples). Participants were mostly male (68.2-72.8%) of median age of 50 years (50-53 years). Non-significant changes in dolutegravir maximum concentration and trough concentration were observed with age at Spearman's test (p values > 0.05); linear logistic regression showed a significant effect of age on dolutegravir trough concentration (p = 0.0013) (Fig. 1). Dolutegravir maximum concentration [3830 ng/mL (2311-5057) vs 4230 ng/mL (2919-5272), p = 0.311] and trough concentration [838 ng/mL (362-1587) vs 966 ng/mL (460-2085), p = 0.056] were non-significantly or borderline higher in patients aged > 50 years. Cerebrospinal dolutegravir concentrations were associated with plasma concentrations (ρ = 0.374, p = 0.016) and age (ρ = 0.537, p = 0.003); cerebrospinal fluid dolutegravir concentrations (13.8 vs 7.3 ng/mL, p = 0.015) and cerebrospinal fluid-to-plasma ratios (0.57 vs 0.32%, p = 0.017] were higher in participants aged > 50 years., Conclusions: We observed an increase in dolutegravir exposure in serum and in cerebrospinal fluid in older patients living with human immunodeficiency virus.

Here, we developed a novel high-performance liquid chromatography (HPLC) method for quantification of perampanel in clinical practice and investigated the relationships between the plasma concentrations of perampanel obtained by this HPLC method and the CYP3A4*1G polymorphism. The developed HPLC method was validated based on US Food and Drug Administration. The developed HPLC method could be performed with a plasma volume of only 200 μL and had a limit of quantification (LOQ) of 2.5 ng/mL. The coefficients of variation (CVs) for intra- and inter-day assays were less than 10.4 and 7.2%, respectively, and the accuracy was <2.4% for both assays. A total of 12 patients who received 2 mg perampanel had C0 values ranging from 70.5 to 451 ng/mL, and the CV showed a large variation of 51.4%. No correlations were observed between the dose-adjusted C0 and the CYP3A4*1G polymorphism. This method was superior to previously reported methods in terms of plasma volume and LOQ and was clinically applicable. Perampanel showed high variations in individual plasma concentrations; however, individual differences could not be predicted from analysis of the CYP3A4*1G polymorphism before perampanel administration. Therefore, after beginning perampanel treatment, the dose should be determined based on the observed plasma concentration., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Approximately 1-2% of patients with non-valvular atrial fibrillation have an acute ischemic stroke (AIS) while on direct oral anticoagulant (DOAC) treatment every year. However, current evidence on stroke subtypes, pathophysiology and factors leading to the failure of DOAC preventive therapy in a "real world" setting is still scanty. This study aimed at investigating whether there is any relationship between DOAC plasma levels and the stroke occurrence, on the basis of the phenotypic classification and pathophysiology of the stroke, in a cohort of DOAC-treated patients admitted to our hospital for AIS over 1-year period. A total of 28 patients had DOAC plasma levels determined in emergency and were included in the study, nine patients receiving dabigatran, 11 rivaroxaban and 8 apixaban. The DOAC levels were low in 8/28 patients (28.6% of the sample), intermediate in 4 (14.3%) and high in 16 (57.1%). The most prevalent stroke subtype was the small vessel disease, according to the A-S-C-O phenotypic classification, in 53.6% of our sample. The most common clinical presentation was "minor stroke" in 71.4% of the cases. There was a significantly higher proportion of patients with high DOAC levels in the small vessel group, compared to the cardioembolic group without other phenotypes. The question arises as to the most suitable clinical management of AIS in these patients on DOACs. In the current absence of clear evidence, taking into account the DOAC levels (low/intermediate/high) and the underlying stroke pathophysiology, we present a flowchart of our proposed clinical management of ischemic stroke in patients while on DOAC.

To evaluate changes in the pharmacokinetics of perampanel after discontinuation of carbamazepine. We enrolled 13 patients receiving perampanel who discontinued carbamazepine therapy between June 2016 and December 2018. Data on serum concentrations were obtained from the therapeutic drug monitoring database of the National Epilepsy Center (Shizuoka, Japan). To compare the pharmacokinetics of perampanel before and after discontinuation of carbamazepine, we determined the concentration/dose (CD) ratio of perampanel (serum level [ng/mL] divided by the dose [mg/kg]). The follow-up period was set to eight weeks following the discontinuation of carbamazepine therapy. The mean baseline CD ratio of perampanel was 1,247 ng/mL/mg/kg which increased markedly over time after discontinuation of carbamazepine, with a mean CD ratio at Weeks 1-2, Weeks 3-4, and Weeks 5-8 of 2,683, 3,914, and 4,220, respectively. At eight weeks, the mean CD ratio of perampanel had increased by 276%. Eleven patients developed adverse events, including dizziness, somnolence, irritability, and ataxia. Five of these 11 patients required perampanel dose reduction within eight weeks after discontinuation of carbamazepine. Two patients achieved seizure-free status at Weeks 5-8. The serum perampanel concentration began to increase from one week after discontinuation of carbamazepine, and continued to rise for eight weeks. Based on these findings, we recommend frequent monitoring of serum perampanel concentration for at least eight weeks after stopping carbamazepine therapy. Monitoring is required as a guide for dose adjustment in order to achieve a safe and effective therapeutic dose of perampanel.

Purpose: To investigate the distribution of plasma apixaban levels and their relationships with clinical outcomes in elderly patients with atrial fibrillation (AF)., Method: The J-ELD AF Registry is a multicenter prospective observational study of Japanese non-valvular AF patients aged ≥75 years taking an on-label dose of apixaban (3015 patients from 110 institutions). Among them, plasma apixaban levels at trough were estimated by anti-Xa assay (Api-AXA) in 943 patients. Patients with standard (5 mg bid; n = 431) and reduced (2.5 mg bid; n = 512) dose were further divided into two groups with low and high Api-AXA levels (boundary: median value)., Results: The incidence rates (per 100 person-years) of events in the low- and high-Api-AXA groups were as follows: 1.48 and 1.99 (log-rank test, P = 0.695) for stroke or systemic embolism, 0.98 and 1.49 (P = 0.652) for bleeding requiring hospitalization, and 0.49 and 0.99 (P = 0.565) for total deaths in patients with standard dose, versus 0.84 and 1.68 (P = 0.414), 0.42 and 4.64 (P = 0.004), and 2.52 and 6.65 (P = 0.035) in patients with a reduced dose, respectively. In multivariate Cox regression analysis among patients with a reduced dose, a high Api-AXA level was independently associated with bleeding requiring hospitalization (HR 12.12, 95% CI: 1.56-94.22) and nonsignificantly with total deaths., Conclusions: A high trough apixaban level in patients indicated for standard dose was not associated with adverse events, while a high apixaban level in patients indicated for a reduced dose was associated with bleeding requiring hospitalization.

Stiripentol is an orphan drug successfully used in combination with valproate and clobazam in the treatment of Dravet syndrome. Perampanel has also been added by experts. In this retrospective study, we investigated the influence of stiripentol on perampanel serum levels by using the doses and corresponding perampanel serum levels of 10 patients. The impact of stiripentol on the perampanel serum levels was significant as shown in a linear regression analysis, with perampanel serum levels increasing linearly with the stiripentol doses. We conclude that dose adjustments of stiripentol and perampanel when administered together, should be done carefully to avoid side effects or even severe intoxication. Hence, perampanel serum level monitoring seems advisable., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objective: To evaluate the time course of changes in perampanel levels when co-administered with carbamazepine, and following carbamazepine discontinuation, using a physiologically based pharmacokinetic (PBPK) model., Methods: The PBPK model was developed, verified using clinical PK data, and used to simulate the effect of abrupt discontinuation and down-titration (75 mg twice daily [bid]/wk) of co-administered carbamazepine 300 mg bid on the PK of perampanel once daily (qd). Perampanel dose tapering (8-4 mg) and up-titration (2-6 mg) were simulated during abrupt carbamazepine 300 mg bid discontinuation to identify a titration schedule that minimizes changes in perampanel plasma concentrations., Results: The PBPK model accurately reproduced perampanel plasma concentration-time profiles from clinical studies in single- and multiple-dose regimen simulations, including multiple-dose carbamazepine co-administration. The time course of return to pre-induced perampanel levels occurred more slowly following carbamazepine down-titration (~48 days after first down-titration) vs abrupt discontinuation (~25 days). Perampanel dose tapering (8-4 mg) at abrupt carbamazepine discontinuation produced minimal changes in steady-state concentrations, which returned to the levels observed during carbamazepine co-administration in ~15 days from the time of carbamazepine discontinuation. When perampanel was up-titrated in the presence of carbamazepine, return to steady state occurred more slowly when carbamazepine was down-titrated weekly (~45 days) vs abrupt discontinuation (~24 days)., Conclusion: This PBPK model simulated and predicted optimal perampanel dose tapering and up-titration schedules for maintaining perampanel levels during conversion to monotherapy. These results may guide physicians when managing conversion from perampanel polytherapy with concomitant enzyme-inducing anti-seizure medications to monotherapy., (© 2020 The Authors. Acta Neurologica Scandinavica published by John Wiley & Sons Ltd.)

Background: Pharmacokinetic studies and therapeutic drug monitoring of anticoagulants require a simple, rapid, and reliable analytical method for monitoring plasma concentrations. The aims of the current work were to develop and validate a liquid chromatography/tandem mass spectrometry method for the simultaneous determination of 3 direct oral anticoagulants (dabigatran, rivaroxaban, and apixaban) in human plasma that is suitable for pharmacokinetic studies and routine therapeutic drug monitoring in busy hospital laboratories., Methods: This method included a hydrolysis step to account for the active acylglucuronide metabolites of dabigatran that demonstrate an equivalent anticoagulant effect as dabigatran. After hydrolysis, a simple one-step protein precipitation was used for sample preparation. Total dabigatran (the sum of free dabigatran and the contribution from dabigatran acylglucuronides), rivaroxaban, and apixaban, and their corresponding isotopically labeled internal standards were resolved on a C18(2) column. All compounds were detected using electrospray ionization liquid chromatography/tandem mass spectrometry in the positive mode., Results: For all 3 anticoagulants, standard curves were linear over the concentration range of 1.0-1000 mcg/L (r > 0.99), bias was < ±10%, and intraday and interday coefficients of variation (imprecision) were <10%. The limit of quantification was 1.0 mcg/L. For all 3 anticoagulants and corresponding isotopically labeled internal standards, the absolute recoveries were similar and consistent, with mean values of 93%-102%. No significant matrix effects were observed., Conclusions: This method is simple, rapid, robust, and reliable and can be used to analyze the plasma concentrations of the drugs in patients on dabigatran or rivaroxaban therapy.

Objective: Therapeutic drug monitoring (TDM) of antiepileptic drugs (AEDs) helps optimize drug management for patients with epilepsy. Salivary testing is both noninvasive and easy, and has several other advantages. Due to technical advances, salivary TDM has become feasible for several drugs, including AEDs, and its value has been investigated. Until recently, saliva TDM of perampanel (PER) had not been reported. The purpose of our study was to confirm whether saliva is a biological substitute for plasma in PER TDM., Methods: Adult patients diagnosed with epilepsy who received PER from August 2018 to March 2019 at Seoul National University Hospital were enrolled. Total and free PER were measured in simultaneously obtained plasma and saliva samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatographic (HPLC). We examined the correlations between saliva and plasma PER concentrations and whether the use of concomitant medications classified as cytochrome P450 (CYP)3A4 inducers affected the correlations., Results: Thirty patients were enrolled, aged 16 to 60; 10 (33%) were women. Patients received 2 to 12 mg (mean, 6 mg) of PER. The average total and free concentrations of PER were 343.02 (46.6-818.0) and 1.53 (0.51-2.92) ng/mL in plasma and 9.74 (2.21-33.0) and 2.83 (1.01-6.8) ng/mL in saliva, respectively. A linear relationship was observed between the total PER concentrations in saliva and the total and free PER concentrations in plasma (both P < .001; r = .678 and r = .619, respectively). The change in the PER concentration caused by the CYP3A4 inducer did not affect the correlation between saliva and plasma concentrations (all P < .001)., Significance: The PER concentration in saliva was correlated with that in plasma. This correlation was not affected by CYP3A4 inducers. Our results demonstrate for the first time that PER is measurable in saliva and suggest the potential for the clinical application of the saliva PER TDM matrix., (© 2020 International League Against Epilepsy.)

Background: Antiviral drugs are administered in patients with severe COVID-19 respiratory syndrome, including those treated with direct oral anticoagulants (DOACs). Concomitant administration of antiviral agents has the potential to increase their plasma concentration. A series of patients managed in the Cremona Thrombosis Center were admitted at Cremona Hospital for SARS-CoV-2 and started antiviral drugs without stopping DOAC therapy. DOAC plasma levels were measured in hospital and results compared with those recorded before hospitalization., Methods: All consecutive patients on DOACs were candidates for administration of antiviral agents (lopinavir, ritonavir, or darunavir). Plasma samples for DOAC measurement were collected 2to 4 days after starting antiviral treatment, at 12 hours from the last dose intake in patients on dabigatran and apixaban, and at 24 hours in those on rivaroxaban and edoxaban. For each patient, C-trough DOAC level, expressed as ng/mL, was compared with the one measured before hospitalization., Results: Of the 1039 patients hospitalized between February 22 and March 15, 2020 with COVID-19 pneumonia and candidates for antiviral therapy, 32 were on treatment with a DOAC. DOAC was stopped in 20 and continued in the remaining 12. On average, C-trough levels were 6.14 times higher during hospitalization than in the pre-hospitalization period., Conclusion: DOAC patients treated with antiviral drugs show an alarming increase in DOAC plasma levels. In order to prevent bleeding complications, we believe that physicians should consider withholding DOACs from patients with SARS-CoV-2 and replacing them with alternative parenteral antithrombotic strategies for as long as antiviral agents are deemed necessary and until discharge., (© 2020 International Society on Thrombosis and Haemostasis.)

The widespread use of highly active antiretroviral treatments has dramatically changed the prognosis of people living with HIV (PLWH). However, such treatments have to be taken lifelong raising issues regarding the maintenance of both therapeutic effectiveness and long-term tolerability. Recently approved or investigational antiretroviral drugs present considerable advantages, allowing once daily oral dosage along with activity against resistant variants (eg, bictegravir and doravirine) and also parenteral intramuscular administration that facilitates treatment adherence (eg, long-acting injectable formulations such as cabotegravir and rilpivirine). Still, there remains a risk of insufficient or exaggerated circulating exposure due to absorption issues, abnormal elimination, drug-drug interactions, and others. In this context, a multiplex ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) bioassay has been developed for the monitoring of plasma levels of bictegravir, cabotegravir, doravirine, and rilpivirine in PLWH. A simple and convenient protein precipitation was performed followed by direct injection of the supernatant into the UHPLC-MS/MS system. The four analytes were eluted in less than 3 minutes using a reversed-phase chromatography method coupled with triple quadrupole mass spectrometry detection. This bioassay was fully validated following international guidelines and achieved good performances in terms of trueness (94.7%-107.5%), repeatability (2.6%-11%), and intermediate precision (3.0%-11.2%) over the clinically relevant concentration ranges (from 30 to 9000 ng/mL for bictegravir, cabotegravir, and doravirine and from 10 to 1800 ng/mL for rilpivirine). This sensitive, accurate, and rapid UHPLC-MS/MS assay is currently applied in our laboratory for routine therapeutic drug monitoring of the oral drugs bictegravir and doravirine and is also intended to be applied for the monitoring of cabotegravir/rilpivirine levels in plasma from PLWH receiving once monthly or every 2-month intramuscular injection of these long-acting antiretroviral drugs., (© 2020 The Authors. Journal of Mass Spectrometry published by John Wiley & Sons Ltd.)

Clinical studies are needed to clarify the use of direct oral anticoagulants (DOACs) in breastfeeding women. To support emerging clinical studies on investigating DOAC's transfer into breast milk, an ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for quantifying three DOACs - apixaban, edoxaban and rivaroxaban in human plasma and breast milk. Protein precipitation with methanol was performed for sample preparation. Chromatographic analysis was performed using a C18 column. The MS detection was performed in MRM mode. The method was validated in accordance with the European Guideline (EMA). The calibration range was 5-500 ng/mL in plasma and 5-250 ng/mL in breast milk. The within-batch and between-batch variability remained <9%. Recoveries ranged from 106.13% to 109.05% in plasma and from 93.40% to 107.91% in breast milk. The lot-to-lot matrix variability was within ±15% among a range of samples originating from many different subjects. All analytes were stable when stored for 24 h at room temperature, 7 days at 2-8 °C, and at least 5 weeks at -20 °C in both plasma and breast milk. The developed method fulfilled the EMA bioanalytical method validation guideline and was shown to be simple, fast, accurate and will now be used in a clinical trial evaluating the transfer of apixaban and rivaroxaban into human breast milk., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Declaration of Competing Interest The authors state that they have no conflict of interest., (Copyright © 2020. Published by Elsevier B.V.)

(1) Background: Prescribing apixaban for stroke prevention has significantly increased in patients with non-valvular atrial fibrillation (NVAF). The ABCB 1 genotype can influence apixaban absorption and bioavailability. The aim of the present study was to assess the factors that influence apixaban's plasma level and to establish if a certain relationship has clinical relevance. (2) Methods: Fifty-three NVAF patients were treated with 5 mg apixaban twice/day (70.0 years, range: 65-77, 60.4% men). Trough and peak plasma concentrations of apixaban were determined by liquid chromatography-tandem mass-spectrometry (LC-MS/MS), and ABCB 1 genotyping was performed. (3) Results: Apixaban plasma concentrations varied considerably. They were higher in women than in men (311.2 ng/dL vs. 252.2 ng/dL; p = 0.05) and were lower in patients with heart failure (149.4 ng/dL vs. 304.5 ng/dL; p < 0.01). Creatinine clearance was inversely correlated with the apixaban plasma level (Spearman correlation: r = -0.365; p = 0.007 for trough concentrations). No statistically significant differences between the genotypic groups of ABCB 1 rs1045642 and ABCB 1 rs4148738 were found in the trough or peak apixaban plasma concentrations. (4) Conclusions: Pharmacokinetic parameters are influenced by several clinical factors of which renal function is the major determinant. Plasma concentrations measured in women had higher values than those measured in men, and heart failure was associated with decreased plasma levels of apixaban.