First-Line Durvalumab in Addition to Etoposide and Platinum for Extensive-Stage Small Cell Lung Cancer: A U.S.-Based Cost-Effectiveness Analysis.

BACKGROUND: The latest published CASPIAN trial demonstrated that adding durvalumab to etoposide and platinum (EP) improved survival dramatically for patients with extensive-stage small cell lung cancer (ES-SCLC). Considering the high cost of durvalumab, this study evaluated the cost-effectiveness of durvalumab plus EP (DEP) in the first-line setting for treatment-naïve patients with ES-SCLC from the U.S. payer perspective. MATERIALS AND METHODS: We developed a three-state Markov model to simulate the disease course and source consumption of ES-SCLC over a lifetime horizon. Pseudo-individual patient-level data were generated from digitized Kaplan-Meier curves. Direct medical costs, including drug and administration costs, disease management and adverse events treatment fees, best supportive care and terminal care costs were obtained from sources including the Centers for Medicare and Medicaid Services, Healthcare Cost and Utilization Project, and relevant literature. Health state utility values were derived from published literature. Main outcomes considered were total costs, life-years (LYs), quality-adjusted LYs (QALYs), and incremental cost-effectiveness ratio (ICER). All costs were adjusted for inflation to reflect 2019 U.S. dollars. The willingness-to-pay threshold was set as $150,000/QALY. One-way and probabilistic sensitivity analyses were used to explore the uncertainty of model assumptions. RESULTS: Compared with EP, DEP was projected to increase life expectancy by 0.86 LYs (1.73 vs. 0.87) and 0.44 QALYs (0.93 vs. 0.49). The incremental treatment cost was $95,907, and the corresponding ICER was $216,953/QALY. The result was most sensitive to the variation of durvalumab acquisition cost. Probabilistic sensitivity analysis revealed that the probability of DEP over EP regimen to be cost-effective was 9.4% at a willingness-to-pay threshold of $150,000/QALY. In the case of reducing the price of durvalumab by 30.7%, DEP was more cost-effective than EP. CONCLUSION: From the perspective of the U.S. payer, adding durvalumab to EP is estimated to be not cost-effective compared with EP alone for patients with untreated ES-SCLC. IMPLICATIONS FOR PRACTICE: The information provided by this analysis serves as a reference for decision makers. Lowering the price of durvalumab would be a potential measure to improve the economics of durvalumab plus etoposide and platinum (DEP), and the inclusion of durvalumab in the Medicare pharmacopeia could make DEP more economically available. These results may also guide physicians and patients to choose the most economically feasible treatment.

Drug-Induced Hospital-Acquired Acute Kidney Injury in China: A Multicenter Cross-Sectional Survey.

INTRODUCTION: Drug-induced acute kidney injury (D-AKI) is one of the important types of AKI. The incidence of D-AKI in China has rarely been studied. OBJECTIVE: This study aims to explore the disease burden, related drugs, and risk factors of D-AKI. METHODS: A nationwide cross-sectional survey was conducted in adult patients from 23 academic hospitals in 17 provinces in China. Suspected AKI was screened based on serum creatinine changes in accordance with the 2012 Kidney Disease: Improving Global Outcomes Clinical Practice Guideline for AKI, patients who met the diagnosis of hospital-acquired AKI in January and July of 2014 were defined. Suspected AKI was firstly evaluated for the possibility of D-AKI by pharmacists using the Naranjo Scale and finally defined as D-AKI by nephrologists through reviewing AKI clinical features. RESULTS: Altogether 280,255 hospitalized patients were screened and 1,960 cases were diagnosed as hospital-acquired AKI, among which 735 cases were defined as having D-AKI (37.50%, 735/1,960) with an in-hospital mortality rate of 13.88% and 54.34% of the survivors did not achieve full renal recovery. 1,642 drugs were related to AKI in these patients. Anti-infectives, diuretics, and proton pump inhibitors were the top 3 types of drugs relevant to D-AKI, accounting for 66.63% cumulatively. Besides age, AKI staging, severe disease, hypoalbuminemia, plasma substitute, and carbapenem related D-AKI were independent risk factors for in-hospital mortality of D-AKI patients. CONCLUSION: In China, D-AKI has caused a substantial medical burden. Efforts should be made to pursue nephrotoxic drug stewardship to minimize attributable risk and improve the prevention, diagnosis, and treatment of D-AKI.

Population pharmacokinetics of azathioprine active metabolite in patients with inflammatory bowel disease and dosage regimens optimisation.

Azathioprine is a first-line drug used to maintain the remission of inflammatory bowel disease (IBD). As a prodrug, azathioprine is metabolised to produce active 6-thioguanine nucleotides (6-TGN). There are large individual variations in the pharmacokinetics/pharmacodynamics of 6-TGN in patients with IBD. Here, we aimed to develop a model to quantitatively investigate factors that affect 6-TGN pharmacokinetics to formulate a dosage guideline for azathioprine. Data were collected prospectively from 100 adult patients with IBD who were receiving azathioprine. Patients were genotyped for two single-nucleotide polymorphisms (TPMT*3C c.719A > G and NUDT15 c.415C > T). Using high-performance liquid chromatography, we measured 156 steady-state trough concentrations of 6-TGN within the range 0.09 to 1.16 mg/L (ie 133-1733 pmol per 8 × 108 RBC). The covariates analysed included sex, age, body-weight, laboratory tests and concomitant medications. A population pharmacokinetic model was established using "non-linear mixed-effects modelling" software and the "first-order conditional estimation method with interaction." Body-weight, TPMT*3C polymorphisms and co-therapy with mesalazine were found to be important factors influencing the clearance of 6-TGN. A dosage guideline for azathioprine was developed based on the PPK model that enables individualised azathioprine dosing in adult patients with different body-weights, TPMT*3C genotypes and co-administration with mesalazine.

Glomerular Filtration Rate Is a Major Predictor of Clearance of Oxcarbazepine Active Metabolite in Adult Chinese Epileptic Patients: A Population Pharmacokinetic Analysis.

BACKGROUND: Oxcarbazepine (OXC) is almost completely metabolized to its10-monohydroxy derivative (MHD), which is responsible for the pharmacological effects of the drug. Several studies have described the population pharmacokinetics (PPK) of MHD in pediatric patients, but little is known about its pharmacokinetics in adult patients. In addition, no study to date has proposed a model to investigate the influence of genetic polymorphisms on MHD pharmacokinetics. The aim of this study was to establish a PPK model of MHD to investigate the effects of genetic polymorphisms in UGT2B7, UGT1A9, ABCB1, and ABCB2 in adult Chinese patients with epilepsy and to develop a new dosage guideline for OXC. METHODS: Data were prospectively collected from 187 adult patients with epilepsy who were taking OXC. MHD trough concentrations were detected by enzyme-multiplied immunoassay. Patients were genotyped for 4 single nucleotide polymorphisms (UGT2B7 802T>C, UGT1A9 I399C>T, ABCB1 3435C>T, and ABCB2 1249G>A). Other covariates included sex, age, body weight (BW), hepato-renal function, and concomitant medications. Data were analyzed using the nonlinear mixed effects modelling software. RESULTS: The apparent clearance (CL) of MHD was significantly influenced by glomerular filtration rate and BW, and was unrelated to other covariates such as genetic polymorphisms and coadministration with levetiracetam, lamotrigine, and topiramate. Moreover, a new dosage guideline was proposed based on the final model to individualize OXC regimens for adult patients with varying BW and renal function. CONCLUSIONS: Glomerular filtration rate was first found as an important covariate influencing MHD CL. A PPK model was established to estimate the individual MHD CL for adult patients taking OXC and may be applied for individualizing doses in the target population.

Population pharmacokinetics of oxcarbazepine active metabolite in Chinese paediatric epilepsy patients and its application in individualised dosage regimens.

PURPOSE: Oxcarbazepine (OXC) is an antiepileptic drug metabolised to active 10-monohydroxy derivative (MHD) following oral administration. There are no MHD population pharmacokinetic (PPK) models that describe the influence of genetic factors on MHD pharmacokinetics (PK). We developed a PPK model of MHD to investigate gene polymorphism of enzymes associated with MHD PK in Chinese paediatric epilepsy patients and evaluated its utility for dose individualisation. METHODS: Data were prospectively collected from 141 paediatric epilepsy patients (aged ≤ 14 years) who received OXC therapy at the First Affiliated Hospital of Fujian Medical University. The trough concentrations at steady state were determined by enzyme-multiplied immunoassay. Patients were genotyped for four single nucleotide polymorphisms (UGT2B7 802T>C, UGT1A9 I399C>T, ABCB1 3435C>T, and ABCB2 1249G>A). Patient gender, age, body weight (BW), hepatorenal function, and co-administrations were recorded. The PPK model was developed using nonlinear mixed-effects modelling software. The clinical performance of the final model was evaluated by including additional paediatric patients (n = 20) in the validation group. RESULTS: Oral clearance of MHD was significantly influenced by BW. The MHD PK was unrelated to the other covariates, such as the four single nucleotide polymorphisms and co-administration with new-generation antiepileptic drugs. The final BW-dependent exponent model showed the best fit with our data and predicted the trough concentrations in the validation group more accurately than the basic model. A new dosing strategy combining the dosage guideline and Bayesian method is proposed to individualise OXC regimens. CONCLUSION: A PPK model was established to estimate individual MHD clearance in paediatric patients taking OXC to develop individualised OXC dosing regimens for Chinese paediatric epilepsy patients.

Genotyping of common EGFR mutations in lung cancer patients by electrochemical biosensor.

In this study, we constructed a sandwich-type biosensor to identify six common types of mutations in exon 19 of the epidermal growth factor receptor (EGFR) gene, and tested them using tissue samples from patients with non-small cell lung carcinomas. Considering the characteristics that different locations of non-complementary in DNA probes resulting in different hybridization efficiency, we investigated the design of DNA capture probes with varying non-complementary sequence locations in an effort to optimize the selectivity of the biosensor. Our results revealed that non-complementary sequences located in the middle of a capture probe allow excellent hybridization specificity and achieve the strongest discrimination between mutations that differ by a single nucleotide. Based on this finding, we designed capture probes to identify six common types of EGFR mutations (del1-del6) successfully. Further, we proposed a grouped testing approach to reduce workload and rapidly identify mutation types. Subsequently, EGFR exon 19 hotspot deletion types in real samples were discriminated by this method. RT-PCR products from lung cancer patients were digested with λ-Exo and analyzed using electrochemical biosensors. The results of our grouped testing approach with optimized biosensors were consistent with that of direct sequencing, suggesting that our proposed protocol can be excellent candidate for genotyping of EGFR mutations in lung cancer patients.

Detection EGFR exon 19 status of lung cancer patients by DNA electrochemical biosensor.

Epidermal growth factor receptor (EGFR) exon 19 mutation status is a very important prediction index for tyrosine kinase inhibitors (TKIs) therapy. In this paper, we constructed a superior selective sandwich-type electrochemical biosensor to detect in-frame deletions in exon 19 of EGFR in real samples of patients with non-small cell lung carcinoma. Based on the characteristics of different hybridization efficiency in different hybridization phase conditions, different region around EGFR exon 19 deletion hotspots was selected to design DNA probes to improve biosensor performance. The results confirm that alteration of deletion location in target deliberately according to different hybridization phase is able to improve selectivity of sandwich-type DNA biosensor. Satisfactory discrimination ability can be achieved when the deletions are located in the capture probe interaction region. In order to improve efficiency of ssDNA generation from dsDNA, we introduce Lambda exonuclease (λ-exo) to sandwich-type biosensor system. EGFR exon 19 statuses of clinical real samples from lung cancer patients can be discriminated successfully by the proposed method. Our research would make the electrochemical biosensor be an excellent candidate for EGFR detection for lung cancer patients.

Population pharmacokinetics of vancomycin in adult Chinese patients with post-craniotomy meningitis and its application in individualised dosage regimens.

PURPOSE: Vancomycin (VCM) is a first-line antibacterial drug used to treat post-craniotomy meningitis (PCM). VCM pharmacokinetic parameters are altered in PCM patients, compared to those in other patients. Although VCM population pharmacokinetics (PPK) has been reported, changes in VCM PPK in adult Chinese PCM patients remain unknown. We developed a VCM PPK model in adult Chinese PCM patients and proposed a new strategy for individualising VCM administration using this model. METHODS: Data was obtained from a prospective study of 100 adult PCM patients in the Neurosurgery Department of the First Affiliated Hospital of Fujian Medical University. The trough concentrations at steady state were determined by enzyme multiplied immunoassay. Nonlinear mixed-effect model software was employed to develop the PPK model. The final model was evaluated using the bootstrap method and normalised prediction error distribution and through the testing of 20 independent adult PCM patients. RESULTS: VCM clearance in PCM patients was higher than that observed in other patients. Creatinine clearance affected VCM clearance, whereas no co-administered drugs influenced VCM pharmacokinetics. Trough concentrations were accurately predicted by the final model, while the prediction errors were less than ±32 %. Moreover, a new strategy for individualising VCM regimens using the PPK model was proposed and validated. CONCLUSIONS: A PPK model was developed to estimate the individual clearance in inpatients receiving intravenously infused VCM and could be used to develop individualised dosing of adult Chinese PCM patients.

High maintenance dose of clopidogrel in patients with high on-treatment platelet reactivity after a percutaneous coronary intervention: a meta-analysis.

OBJECTIVE: High on-treatment platelet reactivity (HTPR) has been linked to cardiovascular (CV) events after a percutaneous coronary intervention. There have been some controversies on whether a high maintenance dose (MD) of clopidogrel is effective for HTPR patients. Thus, we carried out a meta-analysis to assess the efficacy and safety of a high MD of clopidogrel in patients with HTPR. METHODS: Searches of PubMed (from 1966 to May 2014), EMBASE (from 1974 to May 2014), and the Cochrane Library (2 May 2014) were performed. All randomized-controlled trials assessing the efficacy and safety of a high MD of clopidogrel in patients with HTPR were included. RESULTS: A total of eight randomized-controlled trials including 3865 patients were included for analysis. In patients with HTPR, high-dose clopidogrel significantly reduced the risk of major adverse CV events or major adverse cardiac and cerebrovascular events [risk ratio (RR) 0.59; 95% confidence interval (CI) 0.39-0.88], stent thrombosis (RR 0.43; 95% CI 0.20-0.92), and target vessel revascularization (RR 0.31; 95% CI 0.10-0.93), without increasing major bleeding (RR 0.75; 95% CI 0.43-1.31) compared with standard-dose clopidogrel. CONCLUSION: A high MD of clopidogrel may be a feasible and readily available treatment to lower the risk of recurrent CV events in patients with HTPR after undergoing percutaneous coronary intervention, especially in HTPR patients with coronary artery disease and chronic kidney disease.

Population pharmacokinetics of valproic acid in adult Chinese epileptic patients and its application in an individualized dosage regimen.

BACKGROUND: There are several reports describing population pharmacokinetic (PPK) models of valproic acid (VPA). However, little was known in Chinese adult patients with epilepsy. The present study aimed to establish a PPK model for VPA in Chinese adult epileptic patients and to demonstrate its use for dose individualization. METHODS: Data were obtained from a prospective study of 199 adult epileptic patients at 5 hospitals. The trough concentrations at steady state were measured by fluorescence polarization immunoassay. Data were analyzed using the Nonlinear Mixed Effects Model software. The serum trough concentrations at steady state were also measured using samples (n = 20) collected prospectively from a different hospital from those providing the data for deriving the original model. These independent samples served as an evaluation group. RESULTS: The important determinants of apparent VPA clearance were daily dose, body weight, and combination with carbamazepine, phenytoin, or phenobarbital. The final model predicted the individualized doses accurately. A total of 85% of the trough concentrations in the evaluation group were accurately predicted by the final model, whereas the prediction errors of the other patients were all < ± 31%. CONCLUSIONS: A PPK model was developed to estimate the individual clearance for patients taking VPA and could be applied for individualizing doses in the target population.

A population pharmacokinetic model of valproic acid in pediatric patients with epilepsy: a non-linear pharmacokinetic model based on protein-binding saturation.

BACKGROUND AND OBJECTIVE: Valproic acid (VPA) follows a non-linear pharmacokinetic profile in terms of protein-binding saturation. The total daily dose regarding VPA clearance is a simple power function, which may partially explain the non-linearity of the pharmacokinetic profile; however, it may be confounded by the therapeutic drug monitoring effect. The aim of this study was to develop a population pharmacokinetic model for VPA based on protein-binding saturation in pediatric patients with epilepsy. METHODS: A total of 1,107 VPA serum trough concentrations at steady state were collected from 902 epileptic pediatric patients aged from 3 weeks to 14 years at three hospitals. The population pharmacokinetic model was developed using NONMEM(®) software. The ability of three candidate models (the simple power exponent model, the dose-dependent maximum effect [DDE] model, and the protein-binding model) to describe the non-linear pharmacokinetic profile of VPA was investigated, and potential covariates were screened using a stepwise approach. Bootstrap, normalized prediction distribution errors and external evaluations from two independent studies were performed to determine the stability and predictive performance of the candidate models. RESULTS: The age-dependent exponent model described the effects of body weight and age on the clearance well. Co-medication with carbamazepine was identified as a significant covariate. The DDE model best fitted the aim of this study, although there were no obvious differences in the predictive performances. The condition number was less than 500, and the precision of the parameter estimates was less than 30 %, indicating stability and validity of the final model. CONCLUSION: The DDE model successfully described the non-linear pharmacokinetics of VPA. Furthermore, the proposed population pharmacokinetic model of VPA can be used to design rational dosage regimens to achieve desirable serum concentrations.

[Population pharmacokinetic/pharmacodynamic modeling of warfarin by nonlinear mixed effects model].

The study aimed to establish a population pharmacokinetic/pharmacodynamic (PPK/PD) model of warfarin. PCR-RFLP technique was used to genotype the CYP2C9 and VKORC1 polymorphisms of 73 patients. RP-HPLC-UV method was used to determine the 190 plasma concentrations of warfarin. Application of NONMEM, the clinical information and 263 international normalized ratio (INR) monitoring data were used to investigate the effect of genetic, physiological, pathological factors, other medication on clearance and anticoagulant response. The final model of warfarin PPK/PD was described as follows: CL = θCL · (WT/60)θWT · θCYP · eηCL (if CYP2C9*1/*1, θCYP = 1; if *1/*3, θCYP = 0.708); EC50 = θEC50 · θVKOR · eηEC50 (if VKORC1- 1639AA, θVKOR = 1; if GA, θVKOR = 2.01; V = θV; K(E0) = θK(E0); Emax = θEmax; E0 = θE0 · eηE0. Among them, the body weight (WT), CYP2C9 and VKORC1 genotype had conspicuous effect on warfarin PK/PD parameters. The goodness diagnosis, Bootstrap, NPDE verification showed that the final model was stable, effective and predictable. It may provide a reference for opitimizing the dose regimen of warfarin.

Electrochemical genosensor for detection of human mammaglobin in polymerase chain reaction amplification products of breast cancer patients.

Human mammaglobin (MG) has been found to be the most specific molecular marker for the hematogenous spread of breast cancer cells. In our study, an electrochemical impedance spectroscopic DNA biosensor was established for the detection of MG in breast cancer patients. The working conditions for the biosensor, such as immobilization time, rinse process, and hybridization process, were optimized. Under the optimal conditions, the charge transfer resistance of the proposed DNA biosensor shows excellent correlation with the amount of the complementary oligonucleotides in the range from 1.0 × 10(-9) to 2.0 × 10(-8) M. The detection limit is 5.0 × 10(-10) M. The proposed biosensor was used to detect the polymerase chain reaction amplification products of actual clinical breast cancer samples. The results were compared with that obtained by conventional gel electrophoresis. The results indicate that the electrochemical impedance spectroscopic assay is significantly sensitive and time-saving. The simple strategy described here is expected to be used in clinical application for early diagnosis of breast cancer.

Simultaneous voltammetric determination of ascorbic acid, dopamine and uric acid using polybromothymol blue film-modified glassy carbon electrode.

A sensitive and selective electrochemical method for simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA) using an electropolymerized bromothymol blue (BTB)-modified glassy carbon electrode (GCE) was developed. The electrochemically synthesized film was investigated using electrochemical impedance spectroscopy and voltammetric methods. The electrochemical behavior of the polymer-modified electrode depends on film thickness, i.e., the electropolymyerization time. The poly-BTB-modified GCE shows excellent electrocatalytic activity toward the oxidation of AA, DA, and UA in phosphate buffer solution (pH 5.0). The voltametric peak separations of AA/DA, DA/UA, and AA/UA on this modified electrode are 118 mV, 298 mV, and 455 mV, respectively. Therefore the voltammetric responses of these three compounds can be resolved well on the polymer-modified electrode, and simultaneous determination of these three compounds can be achieved. In addition, this modified electrode can be successfully applied to determine AA and DA in injection and UA in urine samples without interference.

[Population pharmacokinetic modeling of flurbiprofen].

The paper is to report the establishment of a population pharmacokinetic model for flurbiprofen (FP), an active metabolite of flurbiprofen axetil (FA). 246 FP serum concentration and clinical data were perspectively collected from 23 general anaesthesia patients receiving FA intravenously before operation in Dentofacial Surgery and Otorhinolaryngology Department of the First Affiliated Hospital of Fujian Medical University. Population pharmacokinetic data analysis was performed using NONMEM software. The measure of Bootstrap was applied for internal validation, while Visual Predictive check was adopted for external validation. The data of FP correspond with two-compartment model. The body weight (WT) had conspicuous effect on clearance and volume of central compartment, while sex, age and daily dose of administration had no marked effect on pharmacokinetic parameter of FP. The basic model was described as follows: CL (L x h(-1)) = 1.28x EXP(ETA(1)), V1 (L) = 5.03x EXP(ETA(2)), Q (L x h(-1)) = 8.5 x EXP(ETA(3)), V2 (L) = 4.39 x EXP(ETA(4)). The final model was described as follows: CL (L x h(-1)) = 1.32 x (WT/60) x EXP(ETA(1)), V1 (L) = 5.23 x (WT/60) x EXP(ETA(2)), Q (L x h(-1)) = 8.45 x EXP(ETA(3)), V2 (L) = 4.37 x EXP(ETA(4)). The population typical value of CL, V1, Q and V2 were: 1.32 L x h(-1), 5.23 L, 8.45 L x h(-1) and 4.37 L, respectively. Bootstrap and visual predictive check show that the final model of FP is stable, effective and predictable. A novel population pharmacokinetic model is developed to estimate the individual pharmacokinetic parameter for patients intravenous injecting FA in terms of patients' characteristics and dosing history, and to design a prior dosage regimen.