Breast cancer
Conditions
Interventions
Green tea supplements
Sponsors
Erasmus MC
Eligibility
Inclusion criteria
Inclusion criteria: 1. Age = 18 years 2. Patients with a confirmed diagnosis of primary or advanced breast cancer, who are on tamoxifen treatment for at least three months (steady state concentration). 3. WHO performance = 1 (see Appendix B) 4. Able and willing to sign the informed consent form prior to screening evaluations 5. Willing to abstain from strong CYP3A4, CYP2D6, CYP2C9/2C19, UGT and P-gp inhibitors or inducers, herbal or dietary supplements or other over-the-counter medication besides paracetamol. (see Appendix C) 6. Willing to abstain from a cup of green tea (<4 h after tamoxifen intake)
Exclusion criteria
Exclusion criteria: 1. Patients with known impaired drug absorption (e.g. gastrectomy and achlorhydria) 2. Patients with an active gastric ulcer 3. Patients with a BMI >35 kg/m2 4. Age >80 years 5. Known serious illness or medical unstable conditions that could interfere with this study requiring treatment (e.g. HIV, hepatitis, Varicella zoster or herpes zoster, organ transplants, kidney failure (GFR<30 ml/min/1.73 m2), serious liver disease (e.g. severe cirrhosis), cardiac and respiratory diseases) 6. A CYP2D6 poor metabolizer or ultra-rapid metabolizer phenotype based on CYP2D6 genotyping outcome 7. Use of strong CYP3A4, CYP2D6, CYP2C9/2C19, UGT and P-gp inhibitors or inducers , herbal or dietary supplements or other over-the-counter medication besides paracetamol (e.g. Veregen, grapefruit, st. Johns-wort)
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| To compare the change from baseline of the Area under the curve (AUC) of tamoxifen in patients with breast cancer treated with tamoxifen with and without green tea supplements | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. To compare the Area under the Curve (AUC) of endoxifen in patients with breast cancer treated with tamoxifen with and without green tea. 2. To compare other tamoxifen and endoxifen pharmacokinetic outcomes (i.e. clearance, maximum concentration (Cmax), minimal concentration (Ctrough) and time until maximum concentration (tmax) and elimination half-life (t½)). in patients with breast cancer treated with tamoxifen with and without green tea. 3. To evaluate the incidence and severity of side-effects of treatment with tamoxifen in absence and presence of green tea. | — |
Contacts
Public ContactCornelis Louwrens Braal
Erasmus MC Cancer Institute
Outcome results
None listed