Prospective evaluation of the pharmacokinetics and toxicity profile of docetaxel in the elderly

Purpose: To prospectively study the pharmacokinetics and toxicity profile of docetaxel in elderly patients with cancer. Patients and Methods: Docetaxel was administered at a dose 75 mg/m² once every 3 weeks to 25 elderly cancer patients aged ≥ 65 years and 26 cancer patients aged younger than 65 years. Pharmacokinetic studies and toxicity assessments were performed during the first cycle of therapy. Results: Of 51 patients treated, 20 aged ≥ 65 years (median, 71 years; range, 65 to 80 years) and 20 aged younger than 65 years (median, 53 years; range, 26 to 64 years) were assessable for pharmacokinetic studies, and 39 were assessable for toxicity. Patient characteristics were similar (P ≥ .15) between the two cohorts. Mean docetaxel clearance was not altered in the elderly versus younger patients: 30.1 L/h (standard deviation [SD] 18.3 L/h) v 30.0 L/h (SD, 14.8 L/h; P = .98). The percentage of patients with grade 4 and febrile neutropenia was higher in the elderly (63% and 16%, respectively) versus younger (30% and 0%, respectively) cohort, although this observation did not reach a level of statistical significance (P = .056). From logistic regression analysis, the odds ratio for a patient aged 65 years was 1.98 for developing grade 4 neutropenia compared with a patient aged 50 years (P = .091). Conclusion: Docetaxel plasma pharmacokinetics are unaltered in elderly patients. Patients aged ≥ 65 years appear to be more sensitive to docetaxel-induced neutropenia.