scholarly journals Population Pharmacokinetics of AZD-5847 in Adults with Pulmonary Tuberculosis

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Abdullah Alsultan ◽  
Jennifer J. Furin ◽  
Jeannine Du Bois ◽  
Elana van Brakel ◽  
Phalkun Chheng ◽  
...  
Keyword(s):  
Population Pharmacokinetics ◽  
Phase Ii ◽  
Phase Ii Study ◽  
Compartment Model ◽  
Time Curve ◽  
Free Concentration ◽  
Unbound Fraction ◽  
Once Daily ◽  
Two Compartment Model ◽  
Recent Phase

ABSTRACT AZD-5847 is a new oxazolidinone derivative under development for the treatment of tuberculosis (TB). Here we describe the population pharmacokinetics (PK) of AZD-5847 in patients with tuberculosis based on a recently completed phase II study. The study included 60 patients with drug-susceptible TB. Patients were randomized to four dosages (500 mg once daily, 1,200 mg once daily, 500 mg twice daily, and 800 mg twice daily). Patients were intensively sampled on days 1 and 14. AZD-5847 pharmacokinetics were best described with a two-compartment model with lag time (T lag) for absorption. AZD-5847 bioavailability was nonlinear and plateaued at 800 mg. We performed deterministic simulation to compare the PK/pharmacodynamics (PD) of AZD-5847, linezolid, and sutezolid. AZD-5847 PK/PD in terms of both area under the concentration-time curve for the free, unbound fraction (fAUC)/MIC and time the free concentration was above the MIC (fT>MIC) were less favorable than those for linezolid and sutezolid. This could help explain the poor bactericidal activity of AZD-5847 in the recent phase II study.

scholarly journals Tedizolid Population Pharmacokinetics, Exposure Response, and Target Attainment

2014 ◽  
Vol 58 (11) ◽  
pp. 6462-6470 ◽  
Author(s):  
S. Flanagan ◽  
J. Passarell ◽  
Q. Lu ◽  
J. Fiedler-Kelly ◽  
E. Ludwig ◽  
...  
Keyword(s):  
Population Pharmacokinetics ◽  
Coefficient Of Variation ◽  
Safety Data ◽  
Absolute Bioavailability ◽  
Optimum Dose ◽  
Target Attainment ◽  
Time Curve ◽  
Unbound Fraction ◽  
Once Daily ◽  
Content Type

ABSTRACTTedizolid phosphate is a novel antibacterial prodrug that is rapidly and extensively converted to its active moiety, tedizolid. We developed a population pharmacokinetics (PK) model for tedizolid using pooled data from seven densely and sparsely sampled clinical trials evaluating oral and intravenous tedizolid. Model-derived exposure estimates were evaluated for relationships to select efficacy and safety outcomes. A two-compartment model with sigmoidal absorption, absolute bioavailability, and linear elimination described the PK data well. Variability was small (clearance, 31% coefficient of variation; volume, 13.4% coefficient of variation), and absolute bioavailability was high (86%). No clinically significant covariate effects on tedizolid PK were found. Based on phase 3 data evaluating 200-mg once-daily tedizolid for acute bacterial skin and skin structure infections (ABSSSI), no relationships were seen between various efficacy outcomes and estimated tedizolid exposure; the estimated exposure range (free-drug area under the concentration-time curve over 24 h at steady state [AUCss(0–24)], 7 to 50 μg · h/ml) in these patients was modest. Safety data modeling, using once-daily doses of up to 400 mg, showed a small increase in the probability of an adverse event with increasing model-estimated tedizolid exposure; no such relationship was observed when specifically evaluating the 200-mg dose. There were no trends in neutrophil or platelet counts with increasing tedizolid exposure. Target attainment simulations for 200-mg tedizolid indicated a 98.31% probability of attaining the target measure (AUC for the free, unbound fraction of a drug [fAUC]/MIC = 3) against aStaphylococcus aureusstrain for which the MIC was ≤0.5 μg/ml. These findings support 200-mg tedizolid once daily as the optimum dose for treatment of ABSSSI.

scholarly journals The Population Pharmacokinetics of Meropenem in Adult Patients With Rifampicin-Sensitive Pulmonary Tuberculosis

2021 ◽  
Vol 12 ◽  
Author(s):  
Ahmed A. Abulfathi ◽  
Veronique de Jager ◽  
Elana van Brakel ◽  
Helmuth Reuter ◽  
Nikhil Gupte ◽  
...  
Keyword(s):  
Body Weight ◽  
Creatinine Clearance ◽  
Population Pharmacokinetics ◽  
Goodness Of Fit ◽  
Compartment Model ◽  
Parameter Estimates ◽  
Final Model ◽  
Once Daily ◽  
Two Compartment Model ◽  
Relative Standard

Background: Meropenem is being investigated for repurposing as an anti-tuberculosis drug. This study aimed to develop a meropenem population pharmacokinetics model in patients with pulmonary tuberculosis and identify covariates explaining inter-individual variability.Methods: Patients were randomized to one of four treatment groups: meropenem 2 g three times daily plus oral rifampicin 20 mg/kg once daily, meropenem 2 g three times daily, meropenem 1 g three times daily, and meropenem 3 g once daily. Meropenem was administered by intravenous infusion over 0.5–1 h. All patients also received oral amoxicillin/clavulanate together with each meropenem dose, and treatments continued daily for 14 days. Intensive plasma pharmacokinetics sampling over 8 h was conducted on the 14th day of the study. Nonlinear mixed-effects modeling was used for data analysis. The best model was chosen based on likelihood metrics, goodness-of-fit plots, and parsimony. Covariates were tested stepwise.Results: A total of 404 concentration measurements from 49 patients were included in the analysis. A two-compartment model parameterized with clearance (CL), inter-compartmental clearance (Q), and central (V1) and peripheral (V2) volumes of distribution fitted the data well. Typical values of CL, Q, V1, and V2 were 11.8 L/h, 3.26 L/h, 14.2 L, and 3.12 L, respectively. The relative standard errors of the parameter estimates ranged from 3.8 to 35.4%. The covariate relations included in the final model were creatinine clearance on CL and allometric scaling with body weight on all disposition parameters. An effect of age on CL as previously reported could not be identified.Conclusion: A two-compartment model described meropenem population pharmacokinetics in patients with pulmonary tuberculosis well. Covariates found to improve model fit were creatinine clearance and body weight but not rifampicin treatment. The final model will be used for an integrated pharmacokinetics/pharmacodynamics analysis linking meropenem exposure to early bactericidal activity.

scholarly journals Serum bactericidal activities and comparative pharmacokinetics of meropenem and imipenem-cilastatin.

1996 ◽  
Vol 40 (1) ◽  
pp. 105-109 ◽  
Author(s):  
M Dreetz ◽  
J Hamacher ◽  
J Eller ◽  
K Borner ◽  
P Koeppe ◽  
...  
Keyword(s):  
Compartment Model ◽  
Pharmacokinetic Parameters ◽  
Time Curve ◽  
Dose Administration ◽  
Microdilution Method ◽  
Two Compartment Model ◽  
Elimination Half ◽  
Renal Clearances ◽  
The Mean ◽  
Bactericidal Activities

The pharmacokinetics and serum bactericidal activities (SBAs) of imipenem and meropenem were investigated in a randomized crossover study. Twelve healthy male volunteers received a constant 30-min infusion of either 1 g of imipenem plus 1 g of cilastatin or 1 g of meropenem. The concentrations of the drugs in serum and urine were determined by bioassay and high-pressure liquid chromatography. Pharmacokinetic parameters were based on an open two-compartment model and a noncompartmental technique. At the end of infusion, the mean concentrations of imipenem and meropenem measured in serum were 61.2 +/- 9.8 and 51.6 +/- 6.5 mg/liter, respectively; urinary recoveries were 48.6% +/- 8.2% and 60.0% +/- 6.5% of the dose in 12 h, respectively; and the areas under the concentration-time curve from time zero to infinity were 96.1 +/- 14.4 and 70.5 +/- 10.3 mg.h/liter, respectively (P < or = 0.02). Imipenem had a mean half-life of 66.7 +/- 10.4 min; that of meropenem was 64.4 +/- 6.9 min. The volumes of distribution at steady state of imipenem and meropenem were 15.3 +/- 3.3 and 18.6 +/- 3.0 liters/70 kg, respectively, and the mean renal clearances per 1.73 m2 were 85.6 +/- 17.6 and 144.6 +/- 26.0 ml/min, respectively. Both antibiotics were well tolerated in this single-dose administration study. The SBAs were measured by the microdilution method of Reller and Stratton (L. B. Reller and C. W. Stratton, J. Infect. Dis. 136:196-204, 1977) against 40 clinically isolated strains. Mean reciprocal bactericidal titers were measured 1 and 6 h after administration. After 1 and 6 h the median SBAs for imipenem and meropenem, were 409 and 34.9 and 97.9 and 5.8, respectively, against Staphylococcus aureus, 19.9 and 4.4 and 19.4 and 4.8, respectively, against Pseudomonas aeruginosa, 34.3 and 2.2 and 232 and 15.5, respectively, against Enterobacter cloacae, and 13.4 and 2.25 and 90.7 and 7.9, respectively, against Proteus mirabilis. Both drugs had rather short biological elimination half-lives and a predominantly renal route of elimination. Both carbapenems revealed high SBAs against clinically important pathogens at 1 h; meropenem had a higher SBA against E. cloacae and P. mirabilis, and the SBA of imipenem against S. aureus was greater than the SBA of meropenem.

Population pharmacokinetic modeling and dosing simulations of tobramycin in pediatric patients with cystic fibrosis

2021 ◽  
Author(s):  
Antonin Praet ◽  
Laurent Bourguignon ◽  
Florence Vetele ◽  
Valentine Breant ◽  
Charlotte Genestet ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Dose Adjustment ◽  
Total Body Weight ◽  
Compartment Model ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Time Curve ◽  
Population Pharmacokinetic Modeling ◽  
Two Compartment Model ◽  
Total Body

Initial dosing and dose adjustment of intravenous tobramycin in cystic fibrosis children is challenging. The objectives of this study were to develop nonparametric population pharmacokinetic (PK) models of tobramycin in children with CF to be used for dosage design and model-guided therapeutic drug monitoring. We performed a retrospective analysis of tobramycin PK data in our CF children center. The Pmetrics package was used for nonparametric population PK analysis and dosing simulations. Both the maximal concentration over the MIC (Cmax/MIC) and daily area under the concentration-time curve to the MIC (AUC 24 /MIC) ratios were considered as efficacy target. Trough concentration (Cmin) was considered as the safety target. A total of 2884 tobramycin concentrations collected in 195 patients over 9 years were analyzed. A two-compartment model including total body weight, body surface area and creatinine clearance as covariates best described the data. A simpler model was also derived for implementation into the BestDose software to perform Bayesian dose adjustment. Both models were externally validated. PK/PD simulations with the final model suggest that an initial dose of tobramycin of 15 to 17.5 mg/kg/day was necessary to achieve Cmax/MIC ≥ 10 values for MIC values up to 2 mg/L in most patients. The AUC 24 /MIC target was associated with larger dosage requirements and higher Cmin. A daily dose of 12.5 mg/kg would optimize both efficacy and safety target attainment. We recommend to perform tobramycin TDM, model-based dose adjustment, and MIC determination to individualize intravenous tobramycin therapy in children with CF.

Phase II Study of Area Under the Plasma-Concentration-Versus-Time Curve–Based Carboplatin Plus Standard-Dose Intravenous Etoposide in Elderly Patients With Small-Cell Lung Cancer

1999 ◽  
Vol 17 (11) ◽  
pp. 3540-3545 ◽  
Author(s):  
Hiroaki Okamoto ◽  
Koshiro Watanabe ◽  
Yutaka Nishiwaki ◽  
Kiyoshi Mori ◽  
Yuzoh Kurita ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Plasma Concentration ◽  
Elderly Patients ◽  
Small Cell Lung Cancer ◽  
Phase Ii ◽  
Phase Ii Study ◽  
Standard Dose ◽  
Small Cell ◽  
Small Cell Lung ◽  
Time Curve

PURPOSE: The target area under the plasma-concentration-versus-time curve (AUC)–based dosing of carboplatin using Calvert's formula is expected to result in more acceptable toxicity and greater efficacy in elderly patients with small-cell lung cancer (SCLC) than the body surface area–based dosing strategy. This phase II study was designed to determine the toxicity and efficacy of carboplatin based on Calvert's formula plus the standard dose of intravenous etoposide for elderly patients with SCLC. PATIENTS AND METHODS: Carboplatin, dosed to a target AUC of 5 × (24-hour creatinine clearance + 25), was given intravenously on day 1 and etoposide 100 mg/m2 was given intravenously on days 1, 2, and 3. Patients aged ≥ 70 years old with a performance status of 0 to 2 were eligible. RESULTS: Thirty-six patients were enrolled onto the study. The patient characteristics were as follows: median age, 73 years; limited disease (LD), 16 patients; and extensive disease (ED), 20 patients. Grades 3 and 4 leukopenia occurred in 57% and 3% of patients, and grades 3 and 4 thrombocytopenia occurred in 40% and 11% of patients, respectively. There was one treatment-related death due to hemoptysis. Other toxicities were relatively mild. There were two complete responses and 25 partial responses, for a response rate of 75%. The median survival time was 10.8 months (LD, 11.6 months; ED, 10.1 months), and the 1-year survival rate was 47%. CONCLUSION: This carboplatin/etoposide combination chemotherapy is an active and relatively nontoxic regimen in elderly patients with SCLC, which suggests that the combination may be suitable for randomized controlled trials.

Randomised phase II study evaluating weekly docetaxel in combination with cisplatin and 5FU or capecitabine in metastatic oesophago-gastric cancer

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 4067-4067 ◽  
Author(s):  
N. Tebbutt ◽  
V. Gebski ◽  
A. Strickland ◽  
D. Gibbs ◽  
E. Walpole ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Phase Ii ◽  
Phase Ii Study ◽  
Haematological Toxicity ◽  
Phase Iii ◽  
Stage Design ◽  
Weekly Docetaxel ◽  
Phase Iii Study ◽  
Recent Phase ◽  
Combination Regimens

4067 Background: Docetaxel (T), cisplatin (C) and 5FU (F) are active agents in oesophago-gastric cancer. A recent phase III study using TCF achieved a survival advantage but was associated with high rates of haematological toxicity (30% incidence of febrile neutropenia/neutropenic infection) as well as non-haematological side effects (Moiseyenko et al, 2005 Pr ASCO abstr 4002). Weekly docetaxel is associated with a lower incidence of haematological toxicity. This randomised phase II study aimed to test weekly docetaxel based combination chemotherapy regimens with the aim of maintaining the activity of docetaxel based combination regimens but reducing toxicity. Methods: Eligibility included; histologically confirmed, metastatic oesophageal or gastric (OG) carcinoma, measurable disease, PS0–2, adequate organ function, no prior treatment, informed consent. Pts were randomised to receive weekly (w) T 30 mg/m2 d1, 8 C 60 mg/m2 d1 F 200 mg/m2/d continuously q 3w or wT 30 mg/m2 d1, d8 and capecitabine (×)1600 mg/m2/d d1–14 q3w. The primary endpoint is confirmed response rate (RR), with each arm analysed independently. Simon’s 2 stage design was used, with 5/21 responses required in the first stage to allow continuation to 48 pts per arm. Results: 79 pts enrolled to date. Protocol specified interim analysis of efficacy after 21 pts per arm and of toxicity after 25 pts per arm ( Table ). In the first 21 pts per arm; 12 responses (11 confirmed) in wTCF arm, 6 responses (5 confirmed) in wTX arm. Trial continues accrual to target of 48 pts per arm. Complete accrual expected by April 2006. Updated data will be presented at the meeting. Conclusions: wTCF and wTX have encouraging activity and and a more favourable toxicity profile than TCF administered 3-weekly. [Table: see text] [Table: see text]

Risk of severe radiation pneumonitis in gemcitabine (GEM) based consolidation chemotherapy after concurrent chemo-radiation (C-RT) in stage III non-small-cell lung cancer (NSCLC)

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 17079-17079 ◽  
Author(s):  
T. Mok ◽  
L. Zhang ◽  
M. Liao ◽  
M. Boyer ◽  
J. Yang ◽  
...  
Keyword(s):  
Phase Ii ◽  
Radiation Pneumonitis ◽  
Phase Ii Study ◽  
Small Cell Lung ◽  
Consolidation Chemotherapy ◽  
Randomized Phase Ii ◽  
Recent Phase ◽  
Ecog Ps ◽  
Fraction Dose ◽  
To Receive

17079 Background: Recent phase II study (S9504) showed that 3 cycles of consolidation docetaxel after C-RT is associated with prolonged survival but 6 pts (7%) had severe (≥gr 3) radiation pneumonitis and 2 (2.4%) died.(None at S9019) LCRG, a multinational Asian study group, designed a randomized phase II study aiming to assess the treatment outcomes of consolidation GEM or GEM/Carboplatin (CAR) after C-RT. GEM is a potent radiation sensitizer with known recall phenomena, thus we evaluated the risk of severe radiation pneumonitis with GEM-based consolidation chemotherapy after C-RT in this interim report. Methods: Enrollment criteria: Histologic proven NSCLC; attained CR/PR/SD after C-RT (Cisplatin-based chemotherapy between 25 mg/m2 and 40 mg/m2 per week or 60 mg/m2 to 100mg/m2 every 3 to 4 weeks; fraction dose not more than 2.0 Gy; total dose not less than 54 Gy and not higher than 64 Gy); ECOG PS 0–1; adequate hematologic/renal/liver function. Patients were screened for eligibility within 6 weeks after C-RT. Eligible patients are randomized to receive GEM 1250mg/m2 day 1,8 q21days with or without CAR 5XAUC day 1. Results: Between 3/04 and 9/05 we screened 51 patients and excluded 19. Six (31.5%) were excluded due to radiation pneumonitis.(gr 1=5 and gr 3 = 1). C-RT induced toxicity was the main reason for difficulty with accrual to this trial. We enrolled 32 patients (m:f 29:3; mean age 58 (40–78); adeno:scc:other 14:16:2; IIIa:IIIb 4:28) Median RT fraction and dose was 30 (27–32) and 60 Gy (54–64), respectively. 19 pts received GEM and 13 received GEM/CAR. Severe (≥gr 3) radiation pneumonitis was reported in 3 pts (9.3%) and 1 (3.1%) died from the complication. Another 10 and 6 pts had grade 1 and 2 radiation pneumonitis, respectively, but without significant clinical compromise. Conclusions: Radiation pneumonitis is common after C-RT with or without consolidation chemotherapy. However, severe radiation pneumonitis is relatively uncommon in pts who received GEM based consolidation chemotherapy after C-RT. A possible explanation is that we have screened out the high risk pts prior to enrollment. [Table: see text]

scholarly journals Ethambutol Pharmacokinetic Variability Is Linked to Body Mass in Overweight, Obese, and Extremely Obese People

2011 ◽  
Vol 56 (3) ◽  
pp. 1502-1507 ◽  
Author(s):  
Ronald G. Hall ◽  
Mark A. Swancutt ◽  
Claudia Meek ◽  
Richard D. Leff ◽  
Tawanda Gumbo
Keyword(s):  
Body Mass ◽  
Compartment Model ◽  
Obese Patients ◽  
Obese People ◽  
Time Curve ◽  
Female Ratio ◽  
Two Compartment Model ◽  
Dosing Regimens ◽  
A Prospective Study ◽  
Male To Female

ABSTRACTWe conducted a prospective study of 18 adult volunteers (male-to-female ratio of 1) whose body mass index fell into categories of <25, 25 to 40, or >40 kg/m2, who received a single oral dose of 1,600 mg ethambutol. Only individuals with normal renal function were recruited. The minimum body mass (M) was 45.6 kg, the median was 90.8 kg, and the maximum weight was 160.4 kg. Ethambutol pharmacokinetics were best described by a two-compartment model. Inclusion of weight as a covariate dramatically improved the model, with a relative likelihood approaching infinity. The typical clearance was 42.6 liters/h. Ethambutol systemic clearance was proportional to (M/45.6)3/4and thus obeyed fractal geometry-based laws. This means that the area under the concentration-time curve (AUC) actually decreased for obese patients compared to that for leaner patients, reducing chances of concentration-dependent toxicity. On the other hand, such reduced AUCs could lead to therapy failure. Thus, new and individualized ethambutol dosing regimens need to be designed for obese and extremely obese patients.

scholarly journals Moxifloxacin Population Pharmacokinetics in Patients with Pulmonary Tuberculosis and the Effect of Intermittent High-Dose Rifapentine

2012 ◽  
Vol 56 (8) ◽  
pp. 4471-4473 ◽  
Author(s):  
Simbarashe P. Zvada ◽  
Paolo Denti ◽  
Hennie Geldenhuys ◽  
Sandra Meredith ◽  
Danelle van As ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Population Pharmacokinetics ◽  
Treatment Completion ◽  
Compartment Model ◽  
High Dose ◽  
Continuation Phase ◽  
Clinically Significant Change ◽  
Antituberculosis Treatment ◽  
Two Compartment Model ◽  
Clinically Significant

ABSTRACTWe described the population pharmacokinetics of moxifloxacin and the effect of high-dose intermittent rifapentine in patients with pulmonary tuberculosis who were randomized to a continuation-phase regimen of 400 mg moxifloxacin and 900 mg rifapentine twice weekly or 400 mg moxifloxacin and 1,200 mg rifapentine once weekly. A two-compartment model with transit absorption best described moxifloxacin pharmacokinetics. Although rifapentine increased the clearance of moxifloxacin by 8% during antituberculosis treatment compared to that after treatment completion without rifapentine, it did not result in a clinically significant change in moxifloxacin exposure.

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