Breast Cancer
Conditions
Keywords
Hormone Receptor Positive Breast Cancer
Brief summary
We hypothesized that subjects with CYP2D6\*10 alleles may have a lower steady state levels of endoxifen due to reduced conversion of tamoxifen to endoxifen. Primary objectives: * To determine the steady state pharmacokinetics of tamoxifen and its metabolites * To test the effects of genetic polymorphisms of CYP2D6 on plasma concentration of tamoxifen and its metabolites in hormone receptor positive women who are taking tamoxifen as adjuvant treatment for breast cancer.
Interventions
None listed
Sponsors
National University Hospital, Singapore
Study design
Observational model
CASE_CROSSOVER
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Signed informed consent. * At least 18 years of age. * On tamoxifen for at least 3 months for adjuvant therapy. * On a stable diet for past 1 week before blood sampling. * Compliant with tamoxifen medication. * Completed adjuvant chemotherapy and/or adjuvant radiation therapy.
Exclusion criteria
• Patients should not be on the list of medications for the last 1 week before accrual to the study
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| To determine the steady state pharmacokinetics of tamoxifen and its metabolites | — |
| To test the effects of genetic polymorphisms of CYP2D6 on plasma concentration of tamoxifen and its metabolites in hormone receptor positive women who are taking tamoxifen as adjuvant treatment for breast cancer. | — |
Countries
Singapore
Outcome results
None listed