scholarly journals Population Pharmacokinetics, Exposure–Response, and Probability of Target Attainment Analyses for Tedizolid in Adolescent Patients With Acute Bacterial Skin and Skin Structure Infections

Author(s):  
Dan Li ◽  
Philip E. Sabato ◽  
Benjamin Guiastrennec ◽  
Aziz Ouerdani ◽  
Hwa-Ping Feng ◽  
...  

Tedizolid phosphate is an oxazolidinone antibacterial agent approved for treatment of gram-positive acute bacterial skin and skin structure infections (ABSSSIs) in patients aged ≥12 years. To support the use of tedizolid phosphate in adolescents with ABSSSIs, a population pharmacokinetic (PK) model, developed using adult and pediatric data, was updated to include PK data from a phase 3 clinical trial (PN012) that evaluated the safety and efficacy of once-daily oral or intravenous 200-mg tedizolid phosphate in adolescents (12 to <18 years) with ABSSSIs, along with emerging data from a phase 1 trial (PN013) in children (2 to <12 years). Updated PK parameter estimates remained similar to the previous model. Body weight was a statistically significant covariate on clearance and volume parameters, with no clinically meaningful effects on exposure in adolescents. Tedizolid exposures in adolescents from PN012 were slightly higher with largely overlapped area under the concentration–time curve distribution compared with adults from previous phase 2 and 3 trials. The probability of PK/pharmacodynamic target attainment at the minimum inhibitory concentration susceptibility breakpoint of 0.5 μg/mL for Staphylococcus and Streptococcus was 100%. As most participants from the PN012 trial were cured, no significant exposure–efficacy relationship was identified. Tedizolid exposures were similar between participants with and without a safety event from PN012; no clear relationship was detected between exposure and safety. Despite lower body weight and higher exposures in adolescents, safety profiles in adolescents were similar to adults. These results support the 200-mg, once-daily intravenous or oral dose of tedizolid phosphate in adolescents with ABSSSIs.

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S427-S428
Author(s):  
Sujata M Bhavnani ◽  
Jeffrey P Hammel ◽  
Elizabeth A Lakota ◽  
Brian D VanScoy ◽  
Yu Nagira ◽  
...  

Abstract Background ME1100 (arbekacin inhalational solution) is an inhaled aminoglycoside being developed to treat patients with hospital-acquired and ventilator-associated bacterial pneumonia (HABP and VABP, respectively). PK-PD target attainment analyses were undertaken to evaluate ME1100 regimens for patients with HABP/VABP arising from Klebsiella pneumoniae (KP), Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA), including those with renal impairment. Methods Data used included a population pharmacokinetic (PPK) model developed using Phase 1 and post-marketing PK data, nonclinical PK-PD targets from one compartment in vitro and/or in vivo infection models, and MIC data. Using parameter estimates from the PPK model (four-compartment model with first-order elimination), total-drug epithelial lining fluid concentration-time profiles were generated for simulated patients with varying creatinine clearance (CLcr; mL/minute/1.73 m2) and by CLcr group. Twice daily (BID) ME1100 regimens ranging from 300 to 900 mg were assessed in simulated patients with CLcr &gt;80 to ≤120 mL/minute/1.73 m2. Percent probabilities of PK-PD target attainment by MIC were determined based on total-drug ELF AUC:MIC ratio targets associated with 1- and 2-log10 CFU reductions from baseline for KP, PA and SA using Day 1 AUC. Regimens in simulated patients with renal impairment that best matched the BID regimen in the normal CLcr group with high percent probabilities of PK-PD target attainment and a low percent probability of Cmin &gt; 2 mg/L were identified. Results ME1100 600 mg BID in simulated patients with CLcr &gt;80 to ≤120 mL/minute/1.73 m2, with 600 mg once daily, 450 mg BID and 600 mg BID in simulated patients with CLcr of 0 to ≤30, &gt;30 to ≤50 and &gt;50 to ≤80 mL/minute/1.73 m2, respectively, achieved high percent probabilities of PK-PD target attainment based on PK-PD targets for a 1-log10 CFU reduction from baseline at relevant MIC values for KP, PA and SA, and relatively lower Cmin values. In simulated patients with varying CLcr who received these regimens, high percent probabilities of PK-PD target attainment were achieved for KP, PA and SA at the upper margins of the MIC distributions (Figures 1–3). Conclusion The data provide support for ME1100 dose selection for patients with HABP/VAPB. Disclosures S. M. Bhavnani, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. J. P. Hammel, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. E. A. Lakota, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. B. D. VanScoy, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. Y. Nagira, Meiji Seika Pharma Co. Ltd.: Employee, Salary. C. M. Rubino, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support. N. Sato, Meiji Seika Pharma Co. Ltd.: Employee, Salary. T. Koresawa, Meiji Seika Pharma Co. Ltd.: Employee, Salary. K. Kondo, Meiji Seika Pharma Co. Ltd.: Employee, Salary. P. G. Ambrose, Meiji Seika Pharma Co. Ltd.: Research Contractor, Research support.


2009 ◽  
Vol 53 (10) ◽  
pp. 4407-4413 ◽  
Author(s):  
Déborah Hirt ◽  
Saik Urien ◽  
Mathieu Olivier ◽  
Hélène Peyrière ◽  
Boubacar Nacro ◽  
...  

ABSTRACT We aimed in this study to describe efavirenz concentration-time courses in treatment-naïve children after once-daily administration to study the effects of age and body weight on efavirenz pharmacokinetics and to test relationships between doses, plasma concentrations, and efficacy. For this purpose, efavirenz concentrations in 48 children were measured after 2 weeks of didanosine-lamivudine-efavirenz treatment, and samples were available for 9/48 children between months 2 and 5 of treatment. Efavirenz concentrations in 200 plasma specimens were measured using a validated high-performance liquid chromatography method. A population pharmacokinetic model was developed with NONMEM. The influence of individual characteristics was tested using a likelihood ratio test. The estimated minimal and maximal concentrations of efavirenz in plasma (C min and C max, respectively) and the area under the concentration-time curve (AUC) were correlated to the decrease in human immunodeficiency virus type 1 RNA levels after 3 months of treatment. The threshold C min (and AUC) that improved efficacy was determined. The target minimal concentration of 4 mg/liter was considered for toxicity. An optimized dosing schedule that would place the highest percentage of children in the interval of effective and nontoxic concentrations was simulated. The pharmacokinetics of efavirenz was best described by a one-compartment model with first-order absorption and elimination. The mean apparent clearance and volume of distribution for efavirenz were 0.211 liter/h/kg and 4.48 liters/kg, respectively. Clearance decreased significantly with age. When the recommended doses were given to 46 of the 48 children, 19% (44% of children weighing less than 15 kg) had C mins below 1 mg/liter. A significantly higher percentage of children with C mins of >1.1 mg/liter or AUCs of >51 mg/liter·h than of children with lower values had viral load decreases greater than 2 log10 copies/ml after 3 months of treatment. Therefore, to optimize the percentage of children with C mins between 1.1 and 4 mg/liter, children should receive the following once-daily efavirenz doses: 25 mg/kg of body weight from 2 to 6 years, 15 mg/kg from 6 to 10 years, and 10 mg/kg from 10 to 15 years. These assumptions should be prospectively confirmed.


2017 ◽  
Vol 61 (6) ◽  
Author(s):  
Abdullah Alsultan ◽  
Rada Savic ◽  
Kelly E. Dooley ◽  
Marc Weiner ◽  
William Whitworth ◽  
...  

ABSTRACT The current treatment used for tuberculosis (TB) is lengthy and needs to be shortened and improved. Pyrazinamide (PZA) has potent sterilizing activity and has the potential to shorten the TB treatment duration, if treatment is optimized. The goals of this study were (i) to develop a population pharmacokinetic (PK) model for PZA among patients enrolled in PK substudies of Tuberculosis Trial Consortium (TBTC) trials 27 and 28 and (ii) to determine covariates that affect PZA PK. (iii) We also performed simulations and target attainment analysis using the proposed targets of a maximum plasma concentration (C max) of >35 μg/ml or an area under the concentration-versus-time curve (AUC) of >363 μg · h/ml to see if higher weight-based dosing could improve PZA efficacy. Seventy-two patients participated in the substudies. The mean (standard deviation [SD]) C max was 30.8 (7.4) μg/ml, and the mean (SD) AUC from time zero to 24 h (AUC0–24) was 307 (83) μg · h/ml. A one-compartment open model best described PZA PK. Only body weight was a significant covariate for PZA clearance. Women had a lower volume of distribution (V/F) than men, and both clearance (CL/F) and V/F increased with body weight. Our simulations show that higher doses of PZA (>50 mg/kg of body weight) are needed to achieve the therapeutic target of an AUC/MIC of >11.3 in >80% of patients, while doses of >80 mg/kg are needed for target attainment in 90% of patients, given specific assumptions about MIC determinations. For the therapeutic targets of a C max of >35 μg/ml and/or an AUC of >363 μg · h/ml, doses in the range of 30 to 40 mg/kg are needed to achieve the therapeutic target in >90% of the patients. Further clinical trials are needed to evaluate the safety and efficacy of higher doses of PZA.


2010 ◽  
Vol 54 (8) ◽  
pp. 3280-3286 ◽  
Author(s):  
Naïm Bouazza ◽  
Déborah Hirt ◽  
Christophe Bardin ◽  
Serge Diagbouga ◽  
Boubacar Nacro ◽  
...  

ABSTRACT We aimed in this study to describe lamivudine concentration-time courses in treatment-naïve children after once-daily administration, to study the effects of body weight and age on lamivudine pharmacokinetics, and to simulate an optimized administration scheme. For this purpose, lamivudine concentrations were measured in 49 children after at least 2 weeks of didanosine-lamivudine-efavirenz treatment. A total of 148 plasma lamivudine concentrations were measured, and a population pharmacokinetic model was developed with NONMEM. The influence of individual characteristics was tested using a likelihood ratio test. Children were divided into two groups, according to their pharmacokinetic parameters, thanks to tree regression analysis. For each patient, the area under the curve was derived from estimated individual pharmacokinetic parameters. Different once-daily doses were simulated in each group, to obtain the same exposure in children as the mean effective exposure in adults (8.9 mg/liter·h). A two-compartment model in which the slope of distribution is assumed to be equal to the absorption rate constant adequately described the data. Parameter estimates were standardized for a mean standard body weight using an allometric model. Children were then divided into 2 groups according to body weight: CL/F was significantly higher in children weighing less than 17 kg (1.12 liters/h/kg) than in children over 17 kg (0.95 liters/h/kg; P = 0.01). The target mean AUC of 8.9 mg/liters·h was obtained with a 10-mg/kg once-daily lamivudine (3TC) dose for children below 17 kg; the recommended dose of 8 mg/kg seems to be sufficient in children weighing more than 17 kg. These assumptions should be prospectively confirmed.


2013 ◽  
Vol 57 (5) ◽  
pp. 2047-2053 ◽  
Author(s):  
Anouk E. Muller ◽  
Anne H. Schmitt-Hoffmann ◽  
Nieko Punt ◽  
Johan W. Mouton

ABSTRACTMonte Carlo simulation (MCS) of antimicrobial dosage regimens during drug development to derive predicted target attainment values is frequently used to choose the optimal dose for the treatment of patients in phase 2 and 3 studies. A criticism is that pharmacokinetic (PK) parameter estimates and variability in healthy volunteers are smaller than those in patients. In this study, the initial estimates of exposure from MCS were compared with actual exposure data in patients treated with ceftobiprole in a phase 3 nosocomial-pneumonia (NP) study (NTC00210964). Results of MCS using population PK data from ceftobiprole derived from 12 healthy volunteers were used (J. W. Mouton, A. Schmitt-Hoffmann, S. Shapiro, N. Nashed, N. C. Punt, Antimicrob. Agents Chemother. 48:1713–1718, 2004). Actual individual exposures in patients were derived after building a population pharmacokinetic model and were used to calculate the individual exposure to ceftobiprole (the percentage of time the unbound concentration exceeds the MIC [percentfT> MIC]) for a range of MIC values. For the ranges of percentfT> MIC used to determine the dosage schedule in the phase 3 NP study, the MCS using data from a single phase 1 study in healthy volunteers accurately predicted the actual clinical exposure to ceftobiprole. The difference at 50%fT> MIC at an MIC of 4 mg/liter was 3.5% for PK-sampled patients. For higher values of percentfT> MIC and MICs, the MCS slightly underestimated the target attainment, probably due to extreme values in the PK profile distribution used in the simulations. The probability of target attainment based on MCS in healthy volunteers adequately predicted the actual exposures in a patient population, including severely ill patients.


Antibiotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 113 ◽  
Author(s):  
Noriyuki Ishihara ◽  
Nobuhiro Nishimura ◽  
Kazuro Ikawa ◽  
Fumi Karino ◽  
Kiyotaka Miura ◽  
...  

The aim of this study was to develop a population pharmacokinetic model for piperacillin (PIPC)/tazobactam (TAZ) in late elderly patients with pneumonia and to optimize the administration planning by applying pharmacokinetic/pharmacodynamic (PK/PD) criteria. PIPC/TAZ (total dose of 2.25 or 4.5 g) was infused intravenously three times daily to Japanese patients over 75 years old. The plasma concentrations of PIPC and TAZ were determined using high-performance liquid chromatography and modeled using the NONMEM program. PK/PD analysis with a random simulation was conducted using the final population PK model to estimate the probability of target attainment (PTA) profiles for various PIPC/TAZ-regimen–minimum-inhibitory-concentration (MIC) combinations. The PTAs for PIPC and TAZ were determined as the fraction that achieved at least 50% free time > MIC and area under the free-plasma-concentration–time curve over 24 h ≥ 96 μg h/mL, respectively. A total of 18 cases, the mean age of which was 86.5 ± 6.0 (75–101) years, were investigated. The plasma-concentration–time profiles of PIPC and TAZ were characterized by a two-compartment model. The parameter estimates for the final model, namely the total clearance, central distribution volume, peripheral distribution volume, and intercompartmental clearance, were 4.58 + 0.061 × (CLcr − 37.4) L/h, 5.39 L, 6.96 L, and 20.7 L/h for PIPC, and 5.00 + 0.059 × (CLcr − 37.4) L/h, 6.29 L, 7.73 L, and 24.0 L/h for TAZ, respectively, where CLcr is the creatinine clearance. PK/PD analysis using the final model showed that in drug-resistant strains with a MIC > 8 μg/mL, 4.5 g of PIPC/TAZ every 6 h was required, even for the patients with a CLcr of 50–60 mL/min. The population PK model developed in this study, together with MIC value, can be useful for optimizing the PIPC/TAZ dosage in the over-75-year-old patients, when they are administered PIPC/TAZ. Therefore, the findings of present study may contribute to improving the efficacy and safety of the administration of PIPC/TAZ therapy in late elderly patients with pneumonia.


2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Ka Lai Yee ◽  
Aziz Ouerdani ◽  
Anetta Claussen ◽  
Rik de Greef ◽  
Larissa Wenning

ABSTRACT Doravirine is a novel nonnucleoside reverse transcriptase inhibitor for the treatment of human immunodeficiency virus 1 (HIV-1) infection. A population pharmacokinetic (PK) model was developed for doravirine using pooled data from densely sampled phase 1 trials and from sparsely sampled phase 2b and phase 3 trials evaluating doravirine administered orally as a single entity or as part of a fixed-dose combination of doravirine-lamivudine-tenofovir disoproxil fumarate. A one-compartment model with linear clearance from the central compartment adequately described the clinical PK of doravirine. While weight, age, and healthy versus HIV-1 status were identified as statistically significant covariates affecting doravirine PK, the magnitude of their effects was not clinically meaningful. Other intrinsic factors (gender, body mass index, race, ethnicity, and renal function) did not have statistically significant or clinically meaningful effects on doravirine PK. Individual exposure estimates for individuals in the phase 2b and 3 trials obtained from the final model were used for subsequent exposure-response analyses for virologic response (proportion of individuals achieving <50 copies/ml) and virologic failure. The exposure-response relationships between these efficacy endpoints and doravirine PK were generally flat over the range of exposures achieved for the 100 mg once-daily regimen in the phase 3 trials, with a minimal decrease in efficacy in individuals in the lowest 10th percentile of steady-state doravirine concentration at 24 h values. These findings support 100 mg once daily as the selected dose of doravirine, with no dose adjustment warranted for the studied intrinsic factors.


2005 ◽  
Vol 49 (2) ◽  
pp. 525-535 ◽  
Author(s):  
Salomé Payen ◽  
Albert Faye ◽  
Alexandra Compagnucci ◽  
Carlo Giaquinto ◽  
Diana Gibbs ◽  
...  

ABSTRACT The objective of the present study was to develop a population pharmacokinetic model for nelfinavir mesylate (NFV) and nelfinavir hydroxy-tert-butylamide (M8), the most abundant metabolite of NFV, in infants vertically infected with human immunodeficiency virus type 1 and participating in the Paediatric European Network for Treatment of AIDS 7 study. Plasma NFV concentrations were determined during repeated NFV administrations (two to three times a day). Eighteen infants younger that age 2 years participated in this study. The doses administered ranged from 71 to 203 mg/kg of body weight/day. Pharmacokinetic parameter estimates were obtained by a compartmental approach by using a kinetic model to simultaneously fit NFV and M8 (active metabolite) concentrations. M8 was shown to be formation rate limited and was characterized by first-order rate constants of formation and elimination. Body weight was found to be a more appropriate predictor than age of the changes in (i) the rate of metabolism, (ii) the elimination rate constant of NFV, and (iii) NFV clearance. Population parameters were computed to account for the relationship between the rate of metabolism and body weight. The estimated NFV and M8 elimination half-lives were 4.3 and 2.04 h, respectively. The estimated NFV clearance was 2.13 liters/h/kg. The M8 concentration-to-NFV concentration ratio was 0.64 ± 0.44. In conclusion, the population pharmacokinetic model describing the dispositions of NFV and M8 should facilitate the design of future studies to elucidate the relative contributions of the parent compound and M8 to the pharmacological and toxic effects of NFV therapy.


2009 ◽  
Vol 54 (3) ◽  
pp. 1111-1116 ◽  
Author(s):  
Jared L. Crandon ◽  
Catharine C. Bulik ◽  
Joseph L. Kuti ◽  
David P. Nicolau

ABSTRACT We evaluated cefepime exposures in patients infected with Pseudomonas aeruginosa to identify the pharmacodynamic relationship predictive of microbiological response. Patients with non-urinary tract P. aeruginosa infections and treated with cefepime were included. Free cefepime exposures were estimated by using a validated population pharmacokinetic model. P. aeruginosa MICs were determined by Etest and pharmacodynamic indices (the percentage of the dosing interval that the free drug concentration remains above the MIC of the infecting organism [f T > MIC], the ratio of the minimum concentration of free drug to the MIC [f C min/MIC], and the ratio of the area under the concentration-time curve for free drug to the MIC [fAUC/MIC]) were calculated for each patient. Classification and regression tree analysis was used to partition the pharmacodynamic parameters for prediction of the microbiological response. Monte Carlo simulation was utilized to determine the optimal dosing regimens needed to achieve the pharmacodynamic target. Fifty-six patients with pneumonia (66.1%), skin and skin structure infections (SSSIs) (25%), and bacteremia (8.9%) were included. Twenty-four (42.9%) patients failed cefepime therapy. The MICs ranged from 0.75 to 96 μg/ml, resulting in median f T > MIC, f C m in/MIC, and fAUC/MIC exposures of 100% (range, 0.8 to 100%), 4.3 (range, 0.1 to 27.3), and 206.2 (range, 4.2 to 1,028.7), respectively. Microbiological failure was associated with an f T > MIC of ≤60% (77.8% failed cefepime therapy when f T > MIC was ≤60%, whereas 36.2% failed cefepime therapy when f T > MIC was >60%; P = 0.013). A similar f T > MIC target of ≤63.9% (P = 0.009) was identified when skin and skin structure infections were excluded. While controlling for the SSSI source (odds ratio [OR], 0.18 [95% confidence interval, 0.03 to 1.19]; P = 0.07) and combination therapy (OR, 2.15 [95% confidence interval, 0.59 to 7.88]; P = 0.25), patients with f T > MIC values of ≤60% were 8.1 times (95% confidence interval, 1.2 to 55.6 times) more likely to experience a poor microbiological response. Cefepime doses of at least 2 g every 8 h are required to achieve this target against CLSI-defined susceptible P. aeruginosa organisms in patients with normal renal function. In patients with non-urinary tract infections caused by P. aeruginosa, achievement of cefepime exposures of >60% f T > MIC will minimize the possibility of a poor microbiological response.


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