| 1. |
- Henningsson, Anja, et al.
(author)
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Population pharmacokinetic modelling of unbound and total plasma concentrations of paclitaxel in cancer patients
- 2003
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In: European Journal of Cancer. - 0959-8049 .- 1879-0852. ; 39:8, s. 1105-1114
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Journal article (peer-reviewed)abstract
- The aim of this study was to validate and further develop a mechanism-based population pharmacokinetic model for paclitaxel (Taxol; Bristol-Myers Squibb Co, Princeton, NJ, USA) based on the knowledge of Cremophor EL (CrEL) micelle entrapment and to evaluate the exposure/toxicity relationships. Paclitaxel (total and unbound) and CrEL concentrations were obtained according to a sparse sampling scheme with on average only 3.5 samples per course from 45 patients with solid tumours who received 3-hour infusions of paclitaxel (final dose range 112-233 mg/m(2)). The present data were predicted well by the mechanism-based model. In addition, bilirubin and body size were found to be significant as covariates. A change in body surface area (BSA) of 0.1 m(2) typically caused a change in clearance (CL) of 22.3 l/h and an increase in bilirubin of 10 microM typically caused a decrease in CL of 41 l/h. Toxicity was best described by a threshold model. In conclusion, even with a sparse sampling scheme, the same mechanism-based binding components as in the previously developed model could be identified. Once the CrEL and total paclitaxel plasma concentrations are known, the unbound concentrations, which are more closely related to the haematological toxicity, can be predicted.
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| 2. |
- Jonsson, Elin, et al.
(author)
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Determination of drug effect on tumour cells, host animal toxicity and drug pharmacokinetics in a hollow-fibre model in rats
- 2000
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In: Cancer Chemotherapy and Pharmacology. - : Springer Science and Business Media LLC. - 0344-5704 .- 1432-0843. ; 46:6, s. 493-500
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Journal article (peer-reviewed)abstract
- PURPOSE Based on the previously published hollow-fibre assay mainly used for early in vivo anticancer drug screening, we wanted to develop an extended hollow-fibre model in which antitumour activity, haematological toxicity and pharmacokinetics could be studied in the same animal. METHOD The breast cancer cell lines MDA-MB-231 and MCF-7 were cultured in semipermeable hollow fibres. The fibres were implanted subcutaneously into immunocompetent male Sprague Dawley rats, and the rats were treated with 5-fluorouracil (5-FU, 125 mg/kg), epirubicin (EPI, 10 mg/kg) or cyclophosphamide (CP, 120 mg/kg) intraperitoneally, the new cyanoguanidine CHS 828 (375 mg/kg or 75 mg/kg x 5) orally, or vehicle only. After 6 days the fibres were retrieved and the cell density was evaluated. Haematological parameters were monitored and two to four samples per animal were drawn to determine the pharmacokinetic parameters in NONMEM. RESULTS Drug treatment had generally low effects on the tumour cells. Of the standard drugs (5-FU, EPI and CP), only CP exerted a statistically significant antiproliferative effect. CHS 828 had only a minor effect as a single dose, but divided into five daily doses had a pronounced effect on both cell lines. 5-FU, EPI and CP all caused a marked decrease in leucocytes, platelets and haemoglobin, while CHS 828 did not seem to affect these parameters. The pharmacokinetics of 5-FU and EPI were in accordance with previously established pharmacokinetic models. The pharmacokinetics of CP and CHS 828 were both described by one-compartment models. CONCLUSIONS This study illustrates the possibility of measuring antitumour effect, haematological toxicity and pharmacokinetics in the same animal using the hollow-fibre model.
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| 4. |
- Quartino, Angelica, et al.
(author)
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Modeling of in vitro drug activity and prediction of clinical outcome in acute myeloid leukemia
- 2007
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In: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 47:8, s. 1014-1021
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Journal article (peer-reviewed)abstract
- The objectives of this study were to develop a population pharmacodynamic model describing the in vitro drug sensitivity of tumor cells and to relate in vitro parameters to clinical outcome. Cell samples from 179 patients with acute myelocytic leukemia were exposed to cytosine arabinoside and daunorubicin, and cytotoxicity was analyzed using the fluorometric microculture cytotoxicity assay. A sigmoid E(max)-model for daunorubicin and an E(max)-model for cytosine arabinoside described the data. The model predicted drug potency (EC(50)) adequately from 1 concentration measurement. A logistic regression on individual in vitro parameters of 46 patients treated with the daunorubicin plus cytosine arabinoside regimen showed that the probability of complete response was significantly (P < .05) related to the product of the E(max)/EC(50) ratio of the two drugs. The findings demonstrate the value of population pharmacodynamic modeling of in vitro drug sensitivity data and a significant relationship between the in vitro parameters and clinical outcome.
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| 5. |
- Simonsen, Lena E., et al.
(author)
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Haematological toxicity following different dosing schedules of 5-fluorouracil and epirubicin in rats
- 2000
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In: Anticancer Research. - 0250-7005 .- 1791-7530. ; 20:3A, s. 1519-1525
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Journal article (peer-reviewed)abstract
- AIM To study the effects of single and fractionated doses of 5-fluorouracil and epirubicin on the leukocyte counts in rats. METHODS Six different dosing patterns of each drug were injected within one day. The leukocytes were followed for 11-15 days. Pharmacokinetic models were developed using NONMEM. Quantitative and qualitative pharmacokinetic-pharmacodynamic relationships were investigated. RESULTS A one-compartment model with non-linear elimination described 5-fluorouracil pharmacokinetics and a three-compartment model described epirubicin concentration data. Sigmoidal or basic Emax-models quantified the relationships between individual AUCs and decreases in leukocytes, for both drugs. Similar relationships between AUC and toxicity were found, regardless of whether the drugs were given as single or fractionated doses. CONCLUSION Quantitative relationships between AUC and the effect on leukocytes were established for 5-fluorouracil and epirubicin. However, no schedule dependence was indicated for the schedules used in the study.
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