Paclitaxel Therapeutic Drug Monitoring - International Association of Therapeutic Drug Monitoring and Clinical Toxicology Recommendations

Paclitaxel, one of the most frequently used anticancer drugs, is dosed by body surface area, which leads to substantial inter-individual variability in systemic drug exposure. We evaluated clinical evidence regarding the scientific rationale and clinical benefit of individualized paclitaxel dosing based on measured systemic concentrations, known as therapeutic drug monitoring (TDM). In retrospective studies, higher systemic exposure is associated with greater toxicity and efficacy of paclitaxel treatment across several disease types and dosing regimens. In prospective trials, TDM reduces variability in systemic exposure, and has been demonstrated to reduce toxicity while retaining treatment efficacy for 3-weekly dosing in patients with advanced non-small cell lung cancer. Despite the demonstrated benefits of paclitaxel TDM, clinical adoption has been limited due to the challenges with sample collection and analysis. Based on our review, we strongly recommend TDM for patients receiving every 3-week paclitaxel in combination with a platinum agent for advanced NSCLC, due to the prospectively demonstrated clinical benefits, and find moderate evidence to recommend TDM for paclitaxel 3-hour infusions for other tumor types and preliminary evidence suggesting potential usefulness for paclitaxel administered by 1-hour infusions.