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Significant effect of age on docetaxel pharmacokinetics in Japanese female breast cancer patients by using the population modeling approach

PURPOSE

Docetaxel is frequently used in the treatment of a wide variety of solid tumors, including breast cancer. The aim of this study is to obtain the population pharmacokinetic parameters of docetaxel in Japanese female patients with breast cancer.

METHODS

Blood samples from 24 patients were collected sequentially before and after docetaxel infusion. Genomic DNA was isolated from the peripheral blood and genotyped for the selected polymorphisms in the candidate genes of drug transporters and metabolizing enzymes. The influence of patient characteristics on the pharmacokinetics of docetaxel was evaluated using the nonlinear-mixed-effect modeling program, NONMEM. As a basis for comparison, the pharmacokinetics of another taxane paclitaxel in 41 separate female patients with breast cancer was calculated.

RESULTS

A two-compartment model adequately described the pharmacokinetic profiles of docetaxel. The population mean estimates of the total body clearance for patients aged 58 years or less and the central volume of distribution for docetaxel were 32.6 L/h and 5.77 L, respectively. In patients over 58 years, the clearance was 24 % higher than that in the younger patients. No influences of the genotypes examined were noted on the clearance of docetaxel. The clearance of paclitaxel was not affected by patient age.

CONCLUSIONS

Patients over the age of 58 years showed significantly higher clearance of docetaxel than that in patients aged 58 years or less. Since the clearance of paclitaxel was not affected by the age, it is possible that the pharmacokinetic mechanisms of docetaxel might be specifically affected by age in females.

Factors influencing treatment adherence and discontinuation in women with breast cancer

SUMMARY 

Although all aspects of breast cancer care rely to some extent on patient behaviors, the endocrine therapies, which are orally administered at home, are the most impacted by nonadherence and nonpersistence. A variety of issues can interfere with a breast cancer patient's adherence and persistence including the following: sociodemographic factors; healthcare team and system-related factors (such as inadequate visit time and poor medication distribution services); condition-related factors (such as prognosis); therapy-related factors (such as side effects); and patient-related factors (such as attitudes, beliefs, perceptions, and expectations). In our review, we describe evidence regarding the most powerful factors mediating adherence and persistence in breast cancer patients, and explore potential interventions to reduce nonadherence and nonpersistence, primarily based on data in patients taking adjuvant endocrine therapy.