Apparent Clearance Research Articles

Combined carbapenem resulted in a 4.48-fold increase in valproic acid clearance: a population pharmacokinetic model in Chinese children and adults with epilepsy or after neurosurgery

Our study aims to explore the pharmacokinetics of valproic acid (VPA) in Chinese patients with epilepsy or after neurosurgery and establish a robust population pharmacokinetics (PPK) model. The PPK model was developed using nonlinear mixed-effects modeling, incorporating a total of 615 VPA plasma concentration data points from 443 Chinese epilepsy or after neurosurgery patients. A one-compartment model with an additive residual model was established. Forward addition and backward elimination strategies were used to assess the impact of covariates on the model parameters. Goodness-of-fit plots, bootstrap, visual predict check and normalized prediction distribution errors were used for model validation. In the final model, the apparent clearance (CL) was estimated using the following formula: CL L/h=0.430×BW/600.787×Cr/50.3−0.253×ALB/39−0.873×egender×eCBP×eIND2 ×eηCL (gender = 0.121 when is female, otherwise = 0; CBP = 1.50 when combined with carbapenems, otherwise = 0; IND2 = 0.15 when combined with oxcarbazepine, carbamazepine, phenobarbital, or phenytoin, otherwise = 0). The volume of distribution (Vd) was estimated using the formula: Vd L=8.66×BW/600.751. Comedication with carbapenems could increase VPA clearance by 4.48 times, and comedication with oxcarbazepine could enhance VPA clearance by 116%. Besides, creatinine and albumin could affect VPA clearance. Goodness-of-fit plots, bootstrap, visual predict check and normalized prediction distribution showed acceptable data fit, stability, and predictability of the model. In our study, a PPK model was utilized to attain a more comprehensive insight into these variables, improving the accuracy and individualization of VPA therapy in Chinese patients with epilepsy or after neurosurgery.

Pharmacometric Analysis to Describe Pharmacokinetics and Exposure-Efficacy Response of Ivermectin in Adolescents Infected with Trichuris trichiura.

The efficacy of the combination therapy of albendazole and ivermectin against Trichuris trichiura infection is higher in Tanzania than in Côte d'Ivoire. This study therefore aimed to investigate the difference between the population pharmacokinetics (PK) at these study sites and to determine if an exposure-response analysis could explain the low efficacy of the combination therapy in Côte d'Ivoire. Twenty-four participants (aged 12-19 years) receiving single doses of ivermectin (200 µg/kg) and albendazole (400 mg) were included in the population PK modeling. A regression analysis was performed to investigate the relationship between the reduction of fecal whipworm eggs and different exposure metrics (peak concentration, area under the plasma drug concentration-time curve [AUC], and time above a certain threshold). The PK profile of ivermectin was best described by a one-compartment model, first-order absorption, and no delay in absorption, with the absorption rate constant estimated as 0.26 per h, an apparent volume of distribution of 162.43 L, and an apparent clearance of 7.82 L/h. In Tanzania, all patients showed a very high reduction in egg count independent of exposure. In Côte d'Ivoire, a relationship was found between higher ivermectin exposure and egg reduction, although not statistically significant. There was no significant difference between the PK profiles at both study sites, despite a difference in clinical outcome. Model-based simulations indicate that higher ivermectin doses such as 400 and 600 µg/kg may be associated with reduced egg count. Larger clinical studies are warranted to explore further the exposure-efficacy response relationship at 200 µg/kg and higher ivermectin doses in adults and children.

Clinical pharmacokinetics and pharmacodynamics of ongericimab: A potential long-acting PCSK9 monoclonal antibody in healthy subjects and patients with hypercholesterolemia: Randomized, double-blind, placebo-controlled phase Ia and Ib/II studies.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases plasma low-density lipoprotein-cholesterol (LDL-C) by decreasing the expression of the LDL-receptor on hepatic cells. Ongericimab (JS002) is a novel PCSK9 monoclonal antibody that exhibits a long-acting LDL-C lowering effect by exclusively inhibiting PCSK9 in pre-clinical studies. Two randomized, double-blind, placebo-controlled trials were conducted to evaluate the safety, tolerability, efficacy, immunogenicity, pharmacokinetic, and pharmacodynamic profiles of ongericimab in healthy subjects and patients with hypercholesterolemia. Eighty-four healthy subjects in the phase Ia study received a single dose of placebo or ongericimab (15-450 mg). Ninety patients with hypercholesterolemia in the phase Ib/II study received placebo or ongericimab 150 mg Q2W, 300 mg Q4W, or 450 mg Q4W for 12 weeks. Ongericimab exhibited non-linear kinetics. The apparent clearance decreased as the dosage increased, with terminal elimination half-life (t1/2) values of 4.5-6.5 days. Overall, ongericimab was well tolerated in both studies. A single dose of ongericimab reduced LDL-C levels by 30%-73% in healthy subjects, and repeated doses of ongericimab reduced LDL-C levels by 67%-80% in patients with hypercholesterolemia. At the end of the dosing interval in the phase Ib/II study, over 70% of patients' LDL-C levels decreased by more than 50% from baseline. The results showed that ongericimab had a significant long-acting LDL-C lowering effect with good safety and potential for clinical application.

Bupropion Increased More than Five Times the Systemic Exposure to Aripiprazole: An In Vivo Study in Wistar albino Rats

Background/Objectives: In psychiatric disorders, antipsychotics and antidepressant medication are often administered together. Aripiprazole, a third-generation antipsychotic drug, is extensively metabolized by CYP2D6 and CYP3A4 isoenzymes, while bupropion, used in depressive disorders, is known as a moderate or strong CYP2D6 enzyme inhibitor. This in vivo experiment aimed to assess the presence of a pharmacokinetic drug interaction between aripiprazole and bupropion and its magnitude on the systemic exposure of aripiprazole. Methods: 24 healthy Wistar albino male rats were included in two study groups. A single dose of 8 mg/kg aripiprazole was given to rats in the reference group, while the test group received repeated doses of bupropion for 6 days, followed by a single dose of aripiprazole. An LC-MS/MS method was developed for the concomitant quantification of aripiprazole and its active metabolite, dehydroaripiprazole, and non-compartmental analysis was employed to assess their pharmacokinetic parameters. Results: The mean AUC0-∞ of aripiprazole increased 5.65-fold (1117.34 ± 931.41 vs. 6311.66 ± 2978.71 hr·ng/mL), the mean Cmax increased by 96.76% and the apparent systemic clearance decreased over 9-fold after bupropion repeated doses. The exposure to aripiprazole’s active metabolite increased as well, having a 4-fold increase in the mean AUC0–∞ (from 461.13 ± 339.82 to 1878.66 ± 1446.91 hr·ng/mL) and a 2-fold increase in the mean Cmax. Conclusions: The total exposure to the aripiprazole parent compound and active moiety significantly increased after bupropion pretreatment in this preclinical in vivo experiment. Clinical studies should further establish the significance of this interaction in humans.

Composition of Higher Alcohols in Different Alcoholic Beverages and Their Metabolic Dynamics in Bama Pigs.

The unique flavour contribution of higher alcohols in alcoholic beverages has received growing attention; however, there is a dearth of information on their in vivo metabolic kinetics. In this study, the composition and content of higher alcohols in different alcoholic beverages from Chinese Baijiu and Lujiu were studied via in vivo analysis using Bama pigs to elucidate the mechanisms for intoxication of alcohol in vitro and in drinkers. Direct injection combined with gas chromatography-mass spectrometry (GC-MS) were used to accurately quantify a total of 14 higher alcohols in five alcoholic beverages. Based on the external standard method, a total content of 289.37-938.33 mg/L was detected, mainly 1-butanol, 3-methyl-1-butanol, 1-hexanol, 2-methyl-1-propanol and 2-butanol. Then, headspace solid-phase microextraction (HS-SPME) and solid-phase extraction (SPE) combined with GC-MS analysis strategy, respectively, were adopted to continuously monitor the changes in the concentrations of ethanol and 11 higher alcohols in the blood within 24 h after gavage of different alcoholic beverages, and the key pharmacokinetic parameters were analysed. The peak concentration (Cmax) and area under curve (AUC) of blood higher alcohols were significantly lower than those of ethanol (p < 0.05), accompanied by a later peak time (Tmax) and a larger apparent clearance rate (CL_F), and there were certain differences between the same higher alcohols in different alcoholic beverages and between different higher alcohols in the same alcoholic beverage. This work provides valuable insights into the metabolism of alcoholic beverages.

Population Pharmacokinetic and Pharmacodynamic of Atorvastatin in Chinese Lung Transplant Recipients.

Atorvastatin is a widely prescribed cholesterol-lowering drug that inhibits 3-hydroxy-3-methylglutaryl coenzyme A reductase to reduce lipid levels. This study aimed to establish a population pharmacokinetic and pharmacodynamic model for atorvastatin in Chinese lung transplant recipients (LTRs), particularly those using voriconazole (VOR) and with different genotypes. It evaluated precise dosing regimens and analyzed the correlation between atorvastatin exposure and clinical outcomes. A nonlinear mixed-effects model was used for the population pharmacokinetic/pharmacodynamic (PK/PD) analysis. A one-compartment population PK model was developed, incorporating VOR, SLCO2A1 rs76906503, and SLC22A8 rs2187383 to assess apparent clearance and volume of distribution. LDL-C was modeled as a biomarker to evaluate atorvastatin efficacy. A Monte Carlo simulation was conducted to assess various dosing schemes and the effects of different covariates on achieving the target LDL concentration. The correlation between atorvastatin exposure and clinical outcomes was also evaluated. Results indicated that the average probability of target attainment for optimal dosing regimens across various covariate results exceeded 45.8%. Dosages of 10, 20, and 40 mg were deemed suitable for LTRs. A lower dose was recommended for LTRs taking VOR or with mutant-type genotypes to avoid overexposure and adverse reactions. The population PK/PD model offers valuable guidance for evaluating atorvastatin dosing regimens in clinical settings, particularly for LTRs using VOR and those with different genotypes.

Population pharmacokinetics of nirmatrelvir/ritonavir in critically ill Chinese COVID-19 patients and recommendations for medication use: a two-center retrospective study

ABSTRACT Background This study aimed to establish population pharmacokinetics (PPK) models of nirmatrelvir/ritonavir in critically ill Chinese patients with the coronavirus disease 2019 (COVID-19) infection, explore factors affecting the pharmacokinetics (PK) of nirmatrelvir/ritonavir. Methods A total of 285 serum samples and clinical data were collected from 152 patients. The PPK models of nirmatrelvir/ritonavir were analyzed using nonlinear mixed-effect modeling (NONMEM) approach. The optimal dosing regimen for patients with different renal function was determined using Monte Carlo simulations. Results The population typical values of apparent clearance (CL/F) and apparent volume of distribution (V/F) of nirmatrelvir were 2.26 L/h and 15.3 L, respectively. Notably, creatinine clearance (CrCL) significantly influenced the PK variation of nirmatrelvir. Monte Carlo simulations suggested that patients with mild-to-moderate renal impairment experienced a 22.0–59.9% increase in the area under the curve (AUC) when they were administered a standard dose of nirmatrelvir compared to those with normal renal function. The AUC in patients with severe renal impairment after administration of 150 mg q12h nirmatrelvir was similar to that in patients with normal renal function after administration of 300 mg q12h nirmatrelvir. Conclusions PPK modeling and simulation provided a reference for the rational clinical application of nirmatrelvir/ritonavir in critically ill Chinese patients.

Population pharmacokinetic and dose-response models of nepadutant, a selective antagonist of the NK2 receptors, in infants with colic.

The aim of the current analyses was to develop a population pharmacokinetic model for nepadutant in infants with colic, and a pharmacokinetic-pharmacodynamic model based on observations of duration of crying and fussing following oral nepadutant administration in infants (3-25 weeks) with colic. The models were developed based on data obtained at baseline and following treatment with placebo, nepadutant 0.1mg/kg or nepadutant 0.5mg/kg administered for 7days. A continuous response variable, duration of crying and fussing in minutes within 2h interval, was assembled based on records from "baby's day" diary. The pharmacokinetics of nepadutant was described by a one-compartment model with first-order absorption and elimination with body weight as a structural covariate incorporated allometrically. For an infant weighing 5.3kg, the estimated apparent clearance was 68.6L/h (12% relative standard error) and exhibited large variability (78% coefficient of variation). The pharmacokinetic-pharmacodynamic model described (i) a circadian rhythm in the response with lowest and highest observations at 4a.m. and 9p.m., respectively, (ii) a placebo effect increasing and flattening out with time in an exponential manner, and (iii) a statistically significant (P < .01) linearly increasing response with dose. The observed and model predicted relative change in response from baseline was -35% and -28% (95% prediction interval -36%; -19%) following placebo, and -44% and -36% (-46%; -27%) after 0.5mg/kg. Population pharmacokinetic and dose-response models were successfully developed characterizing the available nepadutant pharmacokinetics and duration of crying and fussing data in infants.

UGT2B10 is the Major UDP-Glucuronosyltransferase 2B Isoform Involved in the Metabolism of Lamotrigine and is Implicated in the Drug-Drug Interaction with Valproic Acid.

Lamotrigine is a phenyltriazine anticonvulsant that is primarily metabolized by phase II UDP-glucuronosyltransferases (UGT) to a quaternary N2-glucuronide, which accounts for ~ 90% of the excreted dose in humans. While there is consensus that UGT1A4 plays a predominant role in the formation of the N2-glucuronide, there is compelling evidence in the literature to suggest that the metabolism of lamotrigine is catalyzed by another UGT isoform. However, the exact identity of the UGT isoform that contribute to the formation of this glucuronide remains uncertain. In this study, we harnessed a robust reaction phenotyping strategy to delineate the identities and its associated fraction metabolized (fm) of the UGTs involved in lamotrigine N2-glucuronidation. Foremost, human recombinant UGT mapping experiments revealed that the N2-glucuronide is catalyzed by multiple UGT isoforms. (i.e., UGT1A1, 1A3, 1A4, 1A9, 2B4, 2B7, and 2B10). Thereafter, scaling the apparent intrinsic clearances obtained from the enzyme kinetic experiments with our in-house liver-derived relative expression factors (REF) and relative activity factors (RAF) revealed that, in addition to UGT1A4, UGT2B10 was involved in the N2-glucuronidation of lamotrigine. This was further confirmed via chemical inhibition in human liver microsomes with the UGT1A4-selective inhibitor hecogenin and the UGT2B10-selective inhibitor desloratadine. By integrating various orthogonal approaches (i.e., REF- and RAF-scaling, and chemical inhibition), we quantitatively determined that the fm for UGT1A4 and UGT2B10 ranged from 0.42 - 0.64 and 0.32 - 0.57, respectively. Finally, we also provided nascent evidence that the pharmacokinetic interaction between lamotrigine and valproic acid likely arose from the in vivo inhibition of its UGT2B10-mediated pathway.

Pharmacokinetic and Pharmacodynamic Interaction of Finerenone with Diltiazem, Fluconazole, and Ritonavir in Rats.

Finerenone, a novel selective non-steroidal mineralocorticoid receptor antagonist, has been indicated in chronic kidney disease associated with type 2 diabetes mellitus. Considering the potential complications of diabetes, finerenone can be co-administered with various drugs, including fluconazole, diltiazem, and ritonavir. Given that finerenone is a substrate of cytochrome P450 (CYP) 3A4, the concurrent administration of finerenone with CYP3A4 inhibitors (diltiazem or fluconazole or ritonavir) could potentially lead to drug interactions, which may cause adverse events such as hyperkalemia. No studies have investigated interactions between finerenone and diltiazem or fluconazole or ritonavir. Therefore, this study aims to investigate the pharmacokinetic interaction of finerenone with diltiazem or fluconazole or ritonavir and to evaluate the impact of fluconazole on the pharmacodynamics of finerenone. The pharmacokinetic study included four rat groups (n=8 rats/group), including a control group (finerenone alone) and test groups (finerenone pretreated with diltiazem or fluconazole or ritonavir) using both non-compartment analysis (NCA) and population pharmacokinetic (pop-PK) modeling. The pop-PK model was developed using non-linear mixed-effects modeling in NONMEM® (version 7.5.0). In the pharmacodynamic study, serum potassium (K+) levels were measured to assess the effects of fluconazole on finerenone-induced hyperkalemia. The NCA results indicated that the area under the plasma concentration-time curve (AUC) of finerenone increased by 1.86- and 1.95-fold when coadministered with fluconazole and ritonavir, respectively. In contrast, diltiazem did not affect the pharmacokinetics of finerenone. The pharmacokinetic profiles of finerenone were best described by a one-compartment disposition with first-order elimination and dual first-order absorption kinetics. The pop-PK modeling results demonstrated that the apparent clearance of finerenone decreased by 50.3% and 49.2% owing to the effects of fluconazole and ritonavir, respectively. Additionally, the slow absorption rate, which represents the absorption in the distal intestinal tract of finerenone, increased by 55.7% due to the effect of ritonavir. Simultaneously, a pharmacodynamic study revealed that finerenone in the presence of fluconazole caused a significant increase in K+ levels compared with finerenone alone. Coadministration of finerenone with fluconazole or ritonavir increased finerenone exposure in rats. Additionally, the administration of finerenone in the presence of fluconazole resulted in elevated K+ levels in rats. Further clinical studies are required to validate these findings.

Pharmacokinetics and pharmacodynamics of the factor XIa-inhibiting antibody osocimab in healthy male East Asian volunteers: Results from two phase 1 studies.

The pharmacokinetics, pharmacodynamics, immunogenicity, and safety of osocimab single doses in healthy Chinese and Japanese volunteers over 149 days were evaluated. Two phase 1 single-blinded, placebo-controlled studies with 27 Japanese and 50 Chinese participants were conducted. Osocimab was investigated with IV doses of 0.3, 1.25, and 2.5 mg/kg (Chinese study) and 0.3, 1.25, and 5.0 mg/kg (Japanese study), as well as SC doses of 3.0 and 6.0 mg/kg (Chinese study) and 6.0 mg/kg (Japanese study). The maximum plasma concentration was reached 1-3 h and 4-6 days after IV and SC administration, respectively. Osocimab exhibited a deviation from dose-proportional pharmacokinetics for AUC but not Cmax; higher doses had higher apparent clearance and disproportionately lower total exposure. A slightly lower exposure was observed in Japanese compared with Chinese volunteers after IV administration; conversely, relatively higher exposure in Japanese volunteers with SC dosing was identified. Osocimab was associated with a dose-dependent increase in activated partial thromboplastin time (aPTT). Maximal aPTT prolongations were observed 1-4 h and 2-6 days after IV and SC administration, respectively. Anti-drug antibodies of low titer were detected in 1/9 (11.1%) Japanese volunteers administered placebo and 26/40 (65.0%) Chinese volunteers administered osocimab. Adverse events were reported in 8/18 (44.4%) Japanese and 28/40 (70.0%) Chinese volunteers who received osocimab, as well as in 1/9 (11.1%) Japanese and 6/10 (60.0%) Chinese volunteers who received placebo. In conclusion, data did not suggest a clear dose-proportionality for osocimab within the investigated dose range. The effect of osocimab on aPTT was expected per its mechanism of action. Osocimab was generally well tolerated.

Pharmacokinetics of once-daily darunavir/ritonavir in second-line treatment in African children with HIV.

Darunavir is a potent HIV protease inhibitor with a high barrier to resistance. We conducted a nested pharmacokinetic sub-study within CHAPAS-4 to evaluate darunavir exposure in African children with HIV, taking once-daily darunavir/ritonavir for second-line treatment. We used data from the CHAPAS-4 pharmacokinetic sub-study treating children with once-daily darunavir/ritonavir (600/100 mg if 14-24.9 kg and 800/100 mg if ≥25 kg) with either tenofovir alafenamide fumarate (TAF)/emtricitabine (FTC), abacavir/lamivudine or zidovudine/lamivudine. Steady-state pharmacokinetic sampling was done at 0, 1, 2, 4, 6, 8, 12 and 24 hours after observed darunavir/ritonavir intake. Non-compartmental and population pharmacokinetic analyses were used to describe the data and identify significant covariates. Reference adult pharmacokinetic data were used for comparison. We simulated the World Health Organization (WHO) recommended 600/100 mg darunavir/ritonavir dose for the 25-34.9 kg weight band. Data from 59 children with median age and weight 10.9 (range 3.8-14.7) years and 26.0 (14.5-47.0) kg, respectively, were available. A two-compartment disposition model with transit absorption compartments and weight-based allometric scaling of clearance and volume best described darunavir data. Our population achieved geometric mean (%CV) darunavir AUC0-24h, 94.3(50) mg·h/L and Cmax, 9.1(35) mg/L, above adult reference values and Ctrough, 1.5(111) mg/L, like adult values. The nucleoside reverse-transcriptase inhibitor backbone was not found to affect darunavir concentrations. Simulated WHO-recommended darunavir/ritonavir doses showed exposures equivalent to adults. Higher alpha-1-acid glycoprotein increased binding to darunavir and decreased apparent clearance of darunavir. Darunavir exposures achieved in our trial are within safe range. Darunavir/ritonavir can safely be co-administered with TAF/FTC. Both WHO-recommended 600/100 mg and CHAPAS-4 800/100 mg darunavir/ritonavir doses for the 25-34.9 kg weight band offer favourable exposures. The choice between them can depend on tablet availability.

Optimizing tacrolimus dosing in Hispanic renal transplant patients: insights from real-world data.

Tacrolimus, an immunosuppressant used to prevent organ rejection in renal transplant patients, exhibits high inter-patient variability, necessitating therapeutic drug monitoring. Early post-transplant tacrolimus exposure in Hispanics is understudied. Although genotypic information is linked to pharmacokinetic differences, its clinical application remains limited. This study aimed to use a real-world data-driven, pharmacokinetic model-based approach for tacrolimus in Hispanics to determine a suitable initial dose and design an optimal dose titration strategy by simulations to achieve plasma trough concentration target levels of 10-12ng/mL at the earliest. Sparse concentration-time data of tacrolimus were obtained from electronic medical records for self-identified Hispanic subjects following renal transplant. Rich pharmacokinetic literature data was leveraged to estimate structural pharmacokinetic model parameters, which were then fixed in the current analysis. Only apparent clearance was estimated with the sparse tacrolimus data and potential covariates were identified. Simulations of various starting doses and different dose titration strategies were then evaluated. The analysis included 121 renal transplant patients with 2,215 trough tacrolimus concentrations. A two-compartment transit absorption model with allometrically scaled body weight and time-varying hematocrit on apparent clearance adequately described the data. The estimated apparent clearance was 13.7L/h for a typical patient weighing 70kg and at 30% hematocrit, demonstrating a 40% decrease in clearance compared to other patient populations. Model based simulations indicated the best initial dose for the Hispanic population is 0.1mg/kg/day. The proposed titration strategy, with three dose adjustments based on trough levels of tacrolimus, increased the proportion of patients within the target range (10-12ng/mL) more than 2.5-fold and decreased the proportion of patients outside the therapeutic window by 50% after the first week of treatment. Hispanic renal transplant population showed an estimated 40% decrease of apparent clearance in the typical patient compared to other populations with similar characteristics. The proposed dose adjustment attained the target range rapidly and safely. This study advocates for tailored tacrolimus dosing regimens based on population pharmacokinetics to optimize therapy in Hispanic renal transplant recipients.

A Phase 1, Single-Dose Study to Evaluate the Pharmacokinetics and Safety of Bepirovirsen in Adults with Hepatic Impairment and Healthy Participants (B-Assured).

Bepirovirsen is a developmental antisense oligonucleotide (ASO) for treatment of chronic hepatitis B virus infection. No pharmacokinetic (PK) studies comparing participants with hepatic impairment (HI) and healthy participants (HPs) have been conducted with ASOs. Given the target patient population, characterization of bepirovirsen PK in HI was imperative. This phase 1, nonrandomized, open-label study (NCT04971928) evaluated the PKs of a single 300-mg dose of bepirovirsen in participants with HI and matched HPs, enrolled in 2 parts (Part 1: moderate HI; Part 2: mild HI). If no predefined difference in the area under the concentration-time curve from time 0 (predose) to infinite time (AUC0-∞) and maximum observed concentration (Cmax; geometric mean ratio [GMR] 0.5-1.5) was identified in Part 1, findings were applied to mild HI, eliminating Part 2. Participants were monitored for 50days post-treatment and noncompartmental analysis estimated PK parameters. Twenty-four participants (moderate HI, n=12; HP, n=12) received bepirovirsen and completed Part 1. AUC0-∞ and Cmax were lower in participants with moderate HI (GMR 0.69 and 0.67, respectively) than in HPs, while apparent clearance (CL/F)and apparent terminal phase volume of distribution (Vz/F) were higher (GMR 1.44 and 1.64, respectively), but fell within the predefined thresholds of difference for this study. Part 2 was omitted. Adverse events were mild. Moderate HI did not have a clinically relevant impact on bepirovirsen PK or safety.

Population pharmacokinetic analysis of zastaprazan (JP-1366), a novel potassium-competitive acid blocker, in patients and healthy volunteers.

Zastaprazan (JP-1366) is a novel potassium-competitive acid blocker for the treatment of acid-related disorders. We aimed to establish a population pharmacokinetic (PK) model of zastaprazan, thereby characterizing the PK of zastaprazan in patients with gastroesophageal reflux disease (GERD) as well as evaluating the impact of various covariates, including CYP2C19 phenotypes, on zastaprazan PK. This population PK analysis included zastaprazan plasma concentration-time data from 92 patients with erosive GERD and 68 healthy volunteers without any gastrointestinal disorders and was performed using nonlinear mixed-effect modeling. Simulations were conducted to predict zastaprazan PK under various dosing regimens in patients with GERD. The plasma PK of zastaprazan was adequately described by a two-compartment model with Erlang-type absorption (six sequential compartments) and first-order elimination. CYP2C19 phenotypes had no significant effect on zastaprazan PK. The disease status was identified as a significant covariate on apparent clearance of zastaprazan, showing lower values in patients with GERD compared to healthy volunteers. However, the model-based simulation indicated that the impact of disease status on zastaprazan exposure was not clinically meaningful. Overall, the current population PK model successfully characterized the observed zastaprazan PK in both patients with GERD and healthy volunteers.

Individualized dosing parameters for tacrolimus in the presence of voriconazole: a real-world PopPK study.

Significant increase in tacrolimus exposure was observed during co-administration with voriconazole, and no population pharmacokinetic model exists for tacrolimus in renal transplant recipients receiving voriconazole. To achieve target tacrolimus concentrations, an optimal dosage regimen is required. This study aims to develop individualized dosing parameters through population pharmacokinetic analysis and simulate tacrolimus concentrations under different dosage regimens. We conducted a retrospective study of renal transplant recipients who were hospitalized at the Second Xiangya Hospital of Central South University between January 2016 and March 2021. Subsequently, pharmacokinetic analysis and Monte Carlo simulation were employed for further analysis. Nineteen eligible patients receiving tacrolimus and voriconazole co-therapy were included in the study. We collected 167 blood samples and developed a one-compartment model with first-order absorption and elimination to describe the pharmacokinetic properties of tacrolimus. The final typical values for tacrolimus elimination rate constant (Ka), apparent volume of distribution (V/F), and apparent oral clearance (CL/F) were 8.39h-1, 2690L, and 42.87L/h, respectively. Key covariates in the final model included voriconazole concentration and serum creatinine. Patients with higher voriconazole concentration had lower tacrolimus CL/F and V/F. In addition, higher serum creatinine levels were associated with lower tacrolimus CL/F. Our findings suggest that clinicians can predict tacrolimus concentration and estimate optimal tacrolimus dosage based on voriconazole concentration and serum creatinine. The effect of voriconazole concentration on tacrolimus concentration was more significant than serum creatinine. These findings may inform clinical decision-making in the management of tacrolimus and voriconazole therapy in solid organ transplant recipients.

Population Pharmacokinetics of Xeligekimab: An Anti-IL-17A Monoclonal Antibody, in Patients with Moderate to Severe Plaque Psoriasis.

Xeligekimab, a recombinant fully human IgG4 monoclonal antibody, has been strategically developed to target IL-17A and is presently in the developmental phase for treating moderate to severe plaque psoriasis. This study aims to investigate the pharmacokinetic profile of Xeligekimab, utilizing data derived from clinical trials specifically conducted in Chinese patients. The study conducted a population pharmacokinetic (PopPK) analysis involving 614 patients with plaque psoriasis. Examined covariates encompassed demographics, baseline laboratory tests, anti-drug antibodies (ADA), injection site, and disease-related baseline characteristics. Model evaluation utilized goodness-of-fit, prediction-corrected visual prediction check, and bootstrap methods. The clinical significance of covariates statistically associated with Xeligekimab was assessed through simulation analysis. The PopPK model of Xeligekimab demonstrated characteristics of a two-compartment model with first-order absorption and linear elimination. Inter-individual variability (IIV) was estimated for clearance and volume of distribution. For a typical plaque psoriasis patient, the estimated values for absorption rate constant (Ka), apparent clearance (CL/F), central compartment volume (Vc/F), peripheral compartment volume (Vp/F), and inter-compartmental clearance (Q/F) was 0.225 per day, 2.223 L/day, 4.02 L, 4.13 L, and 1.11 L/day, respectively. The estimated IIV for CL/F and Vc/F was 25.8% and 49.8%, respectively. The elimination half-life (t1/2) was approximately 28.5 days. CL/F was significantly influenced by factors such as body weight, age, gender, and baseline total protein. Vc/F was significantly influenced by body weight, age, gender, and baseline albumin. However, the clinical relevance of these covariate effects on exposure parameters was determined to be limited.

Optimizing the dosing regimen of roxadustat in kidney transplant recipients with early post-transplant anemia

IntroductionRoxadustat, an oral inhibitor of hypoxia-inducible factor prolyl hydroxylase domain enzymes, has been approved for the treatment of renal anemia. However, there is a lack of study on its pharmacokinetics in kidney transplant recipients (KTRs) with early posttransplant anemia (PTA). Therefore, the aim of this study is to elucidate the pharmacokinetic characteristics of roxadustat in KTRs with early PTA and optimize the dosing regimen. MethodsA population pharmacokinetic (PopPK) analysis was performed based on 72-hour full concentration-time profiles collected from 52 Chinese KTRs. Covariates influencing exposure were assessed using stepwise covariate modelling. Monte Carlo simulations were conducted to recommend the dosing regimen for patients with different levels of covariates. ResultsPopPK analysis showed that the concentration-time data can be fully described by a two-compartment model. Body weight (BW) and direct bilirubin (DBIL) levels significant affected the apparent clearance of roxadustat. Based on the established model and the estimated exposures of roxadustat by Monte Carlo simulations, a recommended dosing regimen for KTRs with early PTA at varying BW and DBIL levels were developed. Roxadustat at 100 mg three times weekly were suitable for the majority of KTRs with a DBIL level around 3 μmol/L and BW between 50 and 75 kg. The required dose may need to be increased with higher BW and lower DBIL levels, while decreased with lower BW and higher DBIL levels. ConclusionsIt was the first PopPK analysis of roxadustat in KTRs with early PTA, which provide a research basis for optimizing the dosing regimen.

Evaluation of in vivo pharmacokinetic study of the anti-cancer drug imatinib using silkworms as an animal model.

Imatinib is an oral molecular targeted therapy that acts as a tyrosine kinase inhibitor. Silkworms present a promising experimental model for elucidating the pharmacokinetic and toxicity profiles of various compounds. This study aimed to establish an experimental paradigm for investigating the pharmacokinetics of imatinib in silkworms. A comparative analysis of imatinib pharmacokinetic parameters across silkworms, humans, mice, and rats revealed similarities in time to maximum concentration (Tmax) and apparent clearance values between silkworms and humans. However, differences in elimination half-life (t1/2) and apparent volume of distribution between silkworms and humans remained within 5- and 4-fold ranges, respectively. Importantly, mice demonstrated pharmacokinetic parameters closer to those of humans than rats during imatinib studies. Additionally, silkworms and mice exhibit similar Tmax and t1/2 values. This study highlights the potential of silkworms as valuable tools for investigating imatinib metabolism in pharmacokinetic studies. Furthermore, it underscores the applicability of silkworms in elucidating the pharmacokinetic parameters of various molecular-targeted drugs, thus facilitating advancements in drug development and evaluation.

Effect of Hepatic Impairment on the Pharmacokinetics and Pharmacodynamics of SHR4640, a Selective Human Urate Transporter 1 Inhibitor.

This parallel-group, open-label Phase I study evaluated the effect of mild to moderate hepatic impairment on pharmacokinetics (PK), pharmacodynamics (PD), and safety of a single oral dose of SHR4640. Participants with mild or moderate hepatic impairment were enrolled, with each cohort consisting of eight individuals, alongside eight well-matched controls with normal hepatic function. The participants were administered 10 mg SHR4640, and blood samples were collected for PK evaluation over 72 h. Additionally, serum uric acid (sUA) levels were measured to assess PD changes. Safety was evaluated through adverse events, laboratory tests, vital signs, and electrocardiograms. The Cmax of SHR4640 decreased by 15.0% in the mild hepatic impairment group (geometric least squares means of the ratios [GMR] = 0.850, 90% CI: 0.701-1.03) and by 17.5% in the moderate hepatic impairment group (GMR = 0.825, 90% CI: 0.681-1.00). These reductions were not statistically significant compared to the normal hepatic function group. AUC0-t and AUC0-inf were similar across all groups, indicating that overall exposure to the drug was not clinical significantly affected by hepatic impairment. Apparent clearance and volume of distribution of SHR4640 showed no association with the severity of hepatic impairment as measured by the Child-Pugh score. There were no significant differences in the changes in sUA levels from baseline across different levels of hepatic function. SHR4640 is well tolerated in participants with mild or moderate hepatic impairment. Mild and moderate hepatic impairment did not have a clinically relevant impact on PK, PD, and safety of SHR4640. SHR4640 can be used in patients with mild to moderate hepatic impairment without the need for dose adjustment.