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Warfarin is the most widely used oral anticoagulant worldwide, but serious bleeding complications are common. We tested whether genetic variants can identify patients who are at increased risk of bleeding with warfarin and, consequently, those who would derive a greater safety benefit with a direct oral anticoagulant rather than warfarin. ENGAGE AF-TIMI 48 was a randomised, double-blind trial in which patients with atrial fibrillation were assigned to warfarin to achieve a target international normalised ratio of 2·0–3·0, or to higher-dose (60 mg) or lower-dose (30 mg) edoxaban once daily. A subgroup of patients was included in a prespecified genetic analysis and genotyped for variants in CYP2C9 and VKORC1. The results were used to create three genotype functional bins (normal, sensitive, and highly sensitive responders to warfarin). This trial is registered with ClinicalTrials.gov, number NCT00781391. 14 348 patients were included in the genetic analysis. Of 4833 taking warfarin, 2982 (61·7%) were classified as normal responders, 1711 (35·4%) as sensitive responders, and 140 (2·9%) as highly sensitive responders. Compared with normal responders, sensitive and highly sensitive responders spent greater proportions of time over-anticoagulated in the first 90 days of treatment (median 2·2%, IQR 0–20·2; 8·4%, 0–25·8; and 18·3%, 0–32·6; ptrend<0·0001) and had increased risks of bleeding with warfarin (sensitive responders hazard ratio 1·31, 95% CI 1·05–1·64, p=0·0179; highly sensitive responders 2·66, 1·69–4·19, p<0·0001). Genotype added independent information beyond clinical risk scoring. During the first 90 days, when compared with warfarin, treatment with edoxaban reduced bleeding more so in sensitive and highly sensitive responders than in normal responders (higher-dose edoxaban pinteraction=0·0066; lower-dose edoxaban pinteraction=0·0036). After 90 days, the reduction in bleeding risk with edoxaban versus warfarin was similarly beneficial across genotypes. CYP2C9 and VKORC1 genotypes identify patients who are more likely to experience early bleeding with warfarin and who derive a greater early safety benefit from edoxaban compared with warfarin. Daiichi Sankyo.

ObjectiveThe aim of this study was to investigate whether genetic variants can identify patients with venous thromboembolism (VTE) at an increased risk of bleeding with warfarin.MethodsHokusai-venous thromboembolism (Hokusai VTE), a randomised, multinational, double-blind, non-inferiority trial, evaluated the safety and efficacy of edoxaban versus warfarin in patients with VTE initially treated with heparin. In this subanalysis of Hokusai VTE, patients genotyped for variants in CYP2C9 and VKORC1 genes were divided into three warfarin sensitivity types (normal, sensitive and highly sensitive) based on their genotypes. An exploratory analysis was also conducted comparing normal responders to pooled sensitive responders (ie, sensitive and highly sensitive responders).ResultsThe analysis included 47.7% (3956/8292) of the patients in Hokusai VTE. Among 1978 patients randomised to warfarin, 63.0% (1247) were normal responders, 34.1% (675) were sensitive responders and 2.8% (56) were highly sensitive responders. Compared with normal responders, sensitive and highly sensitive responders had heparin therapy discontinued earlier (p<0.001), had a decreased final weekly warfarin dose (p<0.001), spent more time overanticoagulated (p<0.001) and had an increased bleeding risk with warfarin (sensitive responders HR 1.38 [95% CI 1.11 to 1.71], p=0.0035; highly sensitive responders 1.79 [1.09 to 2.99]; p=0.0252).ConclusionIn this study, CYP2C9 and VKORC1 genotypes identified patients with VTE at increased bleeding risk with warfarin.Trial registration numberNCT00986154.

This prospective, single-blind, randomized study was designed to evaluate the effect of genotype-based warfarin dosing compared with standard warfarin dosing in Korean patients with mechanical cardiac valves. Patients were assigned to either the genotype-based dosing group or the standard dosing group using stratified block randomization. The genotype-based dosing equation was adopted from a previous study which included VKORC1 rs9934438, CYP2C9 rs1057910, CYP4F2 rs2108622, and age. Primary outcomes included the percentage of time in the therapeutic range (pTTR): (i) during the first week following initiation of warfarin therapy, (ii) during hospitalization and (iii) until the first outpatient visit. A total of 91 patients were included in the analysis, 42 treated with genotype-based warfarin dosing and 49 treated with standard warfarin dosing. The genotype frequency differences of the three SNPs included in this study (ie, VKORC1, CYP2C9, CYP4F2), between the genotype-based dosing and standard dosing groups were not different. The genotype-based dosing group trended toward higher pTTR when compared with the standard dosing group, although this difference was not statistically significant. In patients with aortic valve replacement, TTR Traditional and TTR Rosendaal were significantly higher in the genotype-based dosing group when compared with the standard dosing group during the first week following treatment initiation [ie, 58.5% vs. 38.1% (p = 0.009) and 64.0% vs. 44.6% (p = 0.012), respectively]. Based on the results, the genotype-guided dosing did not offer a significant clinical advantage, but a possible benefit in patients with aortic valve replacement has been suggested.

Flurbiprofen plays a critical role in clinical pain management. This study aims to elucidate the population pharmacokinetic (PPK) profiles of flurbiprofen's enantiomers, R(-) and S(+)-flurbiprofen in human subjects, following intravenous administration, while investigating the influence of clinical covariates. PPK modeling of flurbiprofen isomers was based on a prospective study that included a total of 67 patients, each of whom had plasma and cerebrospinal fluid (CSF) samples collected at various time points within 5-50 min. Nonlinear mixed effects modeling was performed using Phoenix NLME. The final PPK model was validated using both Bootstrap and visual prediction checks. Modeling was used to assess the effect of demographic, biological, and pharmacogenetic (12 SNPs relatived to CYP2C9, ABCB1, PXR, POR and UGT1A9) covariates on clearance (CL) and apparent volume of distribution (V ) for R(-) and S(+)-flurbiprofen. A two-compartment model best fit the data. All patients were homozygous for the wild-type CYP2C9 allele. Plasma CL of S(+)-flurbiprofen was significantly influenced by ABCB1 (rs1045642) polymorphisms. For R(-)-flurbiprofen, body surface area (BSA) were related to V while POR (rs1057868) polymorphisms were associated with CL. The V for both R(-)- and S(+)-flurbiprofen was found to be larger in CSF compared to plasma. Specifically, the final model estimated the Vd of R(-)-flurbiprofen (CSF 79.1 L VS plasma 17.1 L) and S(+)-flurbiprofen (CSF 32.6 L VS plasma 25.6 L), and the CL of R(-)-flurbiprofen (CSF 0.45L·h VS plasma 11.8L·h and S(+)-flurbiprofen (0.39 L·h VS plasma 16.7 L·h ), respectively. Key covariates of S (+)-flurbiprofen was ABCB1 gene polymorphisms and R-flurbiprofen was POR gene polymorphisms and BSA. The findings may provide support for future dose optimization and the development of novel therapeutic approaches.

Introduction Noscapine is a commonly used cough suppressant, with ongoing research on its anti-inflammatory and anti-tumor properties. The drug has a pronounced pharmacokinetic variability. Objective This evaluation aims to describe the pharmacokinetics of noscapine using a semi-mechanistic population pharmacokinetic model and to identify covariates that could explain inter-individual pharmacokinetic variability. Methods Forty-eight healthy volunteers (30 men and 18 women, mean age 33 years) were enrolled in a randomized, two-period, two-stage, crossover bioequivalence study of noscapine in two different liquid formulations. Noscapine plasma concentrations following oral administration of noscapine 50 mg were evaluated by a non-compartmental analysis and by a population pharmacokinetic model separately. Results Compared to the reference formulation, the test formulation exhibited ratios (with 94.12% confidence intervals) of 0.784 (0.662–0.929) and 0.827 (0.762–0.925) for peak plasma concentrations and area under the plasma concentration–time curve, respectively. Significant differences in p values (< 0.01) were both observed when comparing peak plasma concentrations and area under the plasma concentration–time curve between CYP2C9 genotype-predicted phenotypes. A three-compartmental model with zero-order absorption and first-order elimination process best described the plasma data. The introduction of a liver compartment was able to describe the profound first-pass effect of noscapine. Total body weight and the CYP2C9 genotype-predicted phenotype were both identified as significant covariates on apparent clearance, which was estimated as 958 ± 548 L/h for extensive metabolizers ( CYP2C9*1/*1 and *1/*9 ), 531 ± 304 L/h for intermediate metabolizers with an activity score of 1.5 ( CYP2C9*1/*2 ), and 343 ± 197 L/h for poor metabolizers and intermediate metabolizers with an activity score of 1.0 ( CYP2C9*1/*3 , *2/*3 , and *3/*3 ). Conclusion The current work is expected to facilitate the future pharmacokinetic/pharmacodynamic development of noscapine. This study was registered prior to starting at “Deutsches Register Klinischer Studien” under registration no. DRKS00017760.

It was aimed to underline the importance and explain the meaning of genetic testing in warfarin dosing and investigate and evaluate the contributions of the CYP2C9, VKORC1, and CYP4F2 variants in a Turkish population. Two hundred patients were genotyped for CYP2C9 (rs1799853, rs1057910 and rs56165452), VKORC1 (rs9934438, rs8050894, rs9923231, rs7294 and rs2359612) and CYP4F2 (rs2108622), yet, only 127 patients were found suitable for further evaluation in terms of their personal response to warfarin due to long term usage and available INR and dose usage information. The DNA sequences were determined by the ABI PRISM 3100 Genetic Analyzer to 3130xl System (Applied Biosystems, Foster City, California). Warfarin dose application suggestions by warfaringdosing.org, FDA and MayoClinic were followed. Dose requirements in the Turkish population were found higher than the suggested doses by warfarindosing.org. The multivariate logistic regression analysis reveals the utilization of VCORC1 genetic evaluation is valuable in warfarin dosing (low and moderate vs. high) in this study (p < 0.001). The present study provides findings for clinicians to adapt the genetic data to the daily practice. We observed that the VKORC1 variant showed a more potent impact in warfarin dosing in this study.

To clarify pharmacokinetic-pharmacodynamic (PK-PD) factors associated with the over-anticoagulation response in Asians during warfarin induction therapy, population PK-PD analyses were conducted in an attempt to predict the time-courses of the plasma S-warfarin concentration, Cp(S), and coagulation and anti-coagulation (INR) responses. In 99 Chinese patients we analyzed the relationships between dose and Cp(S) to estimate the clearance of S-warfarin, CL(S), and that between Cp(S) and the normal prothrombin concentration (NPT) as a coagulation marker for estimation of IC50. We also analyzed the non-linear relationship between NPT inhibition and the increase in INR to derive the non-linear index λ. Population analyses accurately predicted the time-courses of Cp(S), NPT and INR. Multivariate analysis showed that CYP2C9*3 mutation and body surface area were predictors of CL(S), that VKORC1 and CYP4F2 polymorphisms were predictors of IC50, and that baseline NPT was a predictor of λ. CL(S) and λ were significantly lower in patients with INR≥4 than in those with INR<4 (190 mL/h vs 265 mL/h, P<0.01 and 3.2 vs 3.7, P<0.01, respectively). Finally, logistic regression analysis revealed that CL(S), ALT and hypertension contributed significantly to INR≥4. All these results indicate that factors associated with the reduced metabolic activity of warfarin represented by CL(S), might be critical determinants of the over-anticoagulation response during warfarin initiation in Asians. ClinicalTrials.gov NCT02065388.

Background Pediatric adenotonsillectomy (A&T) is associated with prolonged pain and functional limitation. Celecoxib is an effective analgesic in adult surgery patients; however, its analgesic efficacy on pain and functional recovery in pediatric A&T patients is unknown. Methods During 2009-2012, children (age 2-18 yr) scheduled for elective A&T were enrolled in a single-centre double-blind randomized controlled trial. Study participants received either oral placebo or celecoxib 6 mg·kg −1 preoperatively, followed by 3 mg·kg −1 twice daily for five doses. The primary outcome was the mean “worst 24-hr pain” scores during postoperative days (PODs) 0-2 on a 100-mm visual analogue scale (VAS). Secondary outcomes for PODs 0-7 included co-analgesic consumption, adverse events, and functional recovery. The impact of the CYP2C9*3 allele – associated with reduced celecoxib hepatic metabolism – on recovery was considered. Results Of the 282 children enrolled, 195 (celecoxib = 101, placebo = 94) were included in the primary outcome analysis. While on treatment, children receiving celecoxib experienced a modest reduction in the average pain experienced over PODs 0-2 (7 mm on a VAS; 95% confidence interval [CI]: 0.3 to 14; P  = 0.04) and a “clinically significant” reduction (≥ 10 mm on a VAS; P  ≤ 0.01) on PODs 0 and 1. During PODs 0-2, the mean acetaminophen consumption was lower in the celecoxib group vs the placebo group (78 mg·kg −1 ; 95% CI: 68 to 89 vs 97 mg·kg −1 ; 95% CI: 85 to 109, respectively; P  = 0.03). No differences in adverse events, functional recovery, or satisfaction were observed by POD 7. The CYP2C9*3 allele was associated with less pain and improved functional recovery. Conclusions A three-day course of oral celecoxib reduces early pain and co-analgesic consumption; however, an increase in dose, dose frequency, and duration of dose may be required for sustained pain relief in the pediatric setting. The CYP2C9*3 allele may influence recovery. This trial was registered at: ClinicalTrials.gov: NCT00849966.

We aimed to assess the cost-effectiveness of pharmacogenetic-guided dosing of warfarin in patients with atrial fibrillation (AF) in the United Kingdom and Sweden. Data from EU-PACT, a randomized controlled trial in newly diagnosed AF patients, were used to model the incremental costs per quality-adjusted life-year (QALY) gained by pharmacogenetic-guided warfarin dosing versus standard treatment over a lifetime horizon. Incremental lifetime costs were £26 and 382 Swedish kronor (SEK) and incremental QALYs were 0.0039 and 0.0015 in the United Kingdom and Sweden, respectively. The corresponding incremental cost-effectiveness ratios (ICERs) were £6 702 and 253 848 SEK per QALY gained. The ICER was below the willingness-to-pay threshold of £20 000 per QALY gained in 93% of the simulations in the United Kingdom and below 500 000 SEK in 67% of the simulations in Sweden. Our data suggest that pharmacogenetic-guided dosing of warfarin is a cost-effective strategy to improve outcomes of patients with AF treated with warfarin in the United Kingdom and in Sweden.

PurposeA previous trial failed to demonstrate the superiority of a demographic-genetic algorithm in predicting warfarin (W) dose over a standard clinical approach. The purpose of the present study is to re-analyse the results in subgroups of patients with differing baseline sensitivity to W, integrated with additional pharmacokinetic data.MethodsThe original trial allocated 180 treatment-naïve patients with non-valvular atrial fibrillation to a control arm (CTL, n = 92) or a genetic-guided arm (GEN, n = 88). Before starting anticoagulation treatment, all patients were genotyped for CYP2C9, VKORC1 and CYP4F2 variants and classified into four quartiles (Q1, Q2, Q3, Q4) according to the algorithm-predicted W maintenance dose. International normalised ratios (INR) and plasma concentrations of S-warfarin [S-W]s and R-warfarin [R-W]s were measured at baseline and on days 5, 7, 9, 12, 15 and 19 of therapy.ResultsIn the lowest dose quartile (Q1), the number of INRs > 3 and mean INR values on days 5 and 7 were significantly higher in CTL than in GEN. In Q3 and Q4, the mean INR values reached therapeutic level (> 2) 2 days later in CTL than in GEN. During follow-up, the mean time courses of INRs and [S-W]s in GEN were remarkably stable in all dose quartiles. Thus, mean changes from starting to final doses were significantly smaller in GEN than in CTL. Plasma concentrations of R-W (a partially active enantiomer) steadily increased from day 5 to day 19 in all Qs in both CTL and GEN, except in the Q1 CTL group, due to the marked dose reduction required.ConclusionsThis analysis showed that the demographic-genetic algorithm used to predict the W dose can identify patients with differing degrees of sensitivity to W and to ‘normalise’ their average anticoagulant responses. The progressive rise in [R-W]s throughout the 19-day follow-up indicates that the (partial) contribution of R-W to the W anticoagulant effect changes continually during the early phase of treatment.