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Updated: Jun 22, 2025
Generation of Prostate Cancer Cell Models of Resistance to the Anti-mitotic Agent Docetaxel
Published on: September 8, 2017
A sub-pharmacological test dose does not predict individual docetaxel exposure in prostate cancer patients
Marise R Heerma van Voss1,2, Jessica Notohardjo3,4, Joyce van Dodewaard-de Jong3
1Meander Medical Center, Department of Internal Medicine, Amersfoort, The Netherlands. m.r.heermavanvoss@amsterdamumc.nl.
Purpose:
Docetaxel is a cytotoxic drug used for first-line treatment of various malignancies. It has a narrow therapeutic index and shows wide interpatient variability in clearance and toxicity. Tools for individual dose optimization are needed to maximize efficacy and avoid toxicity.
Methods:
We performed a proof-of-concept study (EudraCT 2016-003785-77) to evaluate whether pharmacokinetics after a sub-pharmacological test dose of 1000 µg docetaxel (millidose) could be used to predict therapeutic dose exposure. Thirty prostate cancer patients eligible for treatment with docetaxel as part of routine clinical care were included. An intravenous docetaxel millidose was administered 1-7 days prior to therapeutic docetaxel. After both doses plasma docetaxel concentrations were measured by ultra- high performance liquid chromatography-tandem mass spectrometry. The docetaxel clearance was estimated with non-linear mixed effects modeling.
Results:
Geometric mean docetaxel clearance was 57.9 L/h (GCV 78.6%) after admission of a millidose and 40.3 L/h (GCV 60.7%) after admission of a therapeutic dose. The millidose and therapeutic dose in a single patient were not significantly correlated (Spearman's rho R = 0.02, P = 0.92).
Conclusion:
Docetaxel pharmacokinetics at milli- and therapeutic dose level showed insufficient correlation for individual dose optimization. However, the clearance of a docetaxel millidose and full dose are within the same order of magnitude. Therefore, docetaxel millidose pharmacokinetics could potentially facilitate prediction of docetaxel pharmacokinetics at a population level in situations where therapeutic dose levels are impractical, such as pharmacokinetic drug-drug interaction studies or pediatric studies.
Insights
A docetaxel millidose test did not predict individual patient drug exposure. However, docetaxel millidose pharmacokinetics may aid population-level predictions for drug interaction or pediatric studies.
Area of Science:
- Pharmacology
- Oncology
- Clinical Pharmacy
Background:
- Docetaxel is a vital chemotherapy agent with a narrow therapeutic index.
- Significant interpatient variability in docetaxel clearance and toxicity necessitates dose optimization tools.
- Individualized dosing strategies are crucial for maximizing treatment efficacy and minimizing adverse events.
Purpose of the Study:
- To assess the utility of docetaxel millidose pharmacokinetics in predicting therapeutic dose exposure.
- To evaluate the correlation between docetaxel clearance at sub-pharmacological and therapeutic doses.
Main Methods:
- A proof-of-concept study involving 30 prostate cancer patients undergoing routine docetaxel treatment.
- Administration of a 1000 µg intravenous docetaxel millidose 1-7 days before the therapeutic dose.
- Plasma docetaxel concentrations measured via ultra-high performance liquid chromatography-tandem mass spectrometry.
- Docetaxel clearance estimated using non-linear mixed effects modeling.
Main Results:
- Geometric mean docetaxel clearance was 57.9 L/h for the millidose and 40.3 L/h for the therapeutic dose.
- No significant correlation was observed between millidose and therapeutic dose docetaxel clearance within individual patients (Spearman's rho = 0.02, P = 0.92).
Conclusions:
- Docetaxel pharmacokinetics at millidose and therapeutic dose levels lack sufficient correlation for individual dose optimization.
- Despite poor individual correlation, millidose and therapeutic dose clearance are of the same order of magnitude.
- Docetaxel millidose pharmacokinetics may be valuable for population-level predictions in specific scenarios, such as drug-drug interaction or pediatric studies.
