CYP2D6 Genotyping by AmpliChipTM CYP450 for Tamoxifen-Treated Breast Cancer Patients
|ClinicalTrials.gov Identifier: NCT00815555|
Recruitment Status : Unknown
Verified December 2008 by Assaf-Harofeh Medical Center.
Recruitment status was: Recruiting
First Posted : December 30, 2008
Last Update Posted : December 30, 2008
|Condition or disease||Intervention/treatment|
|Breast Cancer||Other: There is no intervention - this is an observational study|
Tamoxifen, the first-line drug for preventing breast cancer relapse, is typically prescribed for a 5-year follow-up period after diagnosis and primary treatment of estrogen receptor-positive breast cancer. Recent studies show that tamoxifen is only a pro-drug, while its major active metabolite, endoxifen, is formed in vitro by the liver enzyme CYP2D6. Preliminary observations from the US and Italy have suggested that tamoxifen is less efficacious for cancer relapse prevention in patients with deficient CYP2D6 activities. The FDA is currently reviewing the new data and is likely to modify the tamoxifen label accordingly. It was suggested that an aromatase inhibitor drug such as letrozole might be more beneficial for these patients.
The proposed study would retrospectively test CYP2D6 genotypes in 200 - 300 estrogen receptor (ER) positive breast cancer patients who are treated with tamoxifen post-operatively. Blood collected with informed consent would be used for examining the patients CYP2D6 genotype, and identifying those who are CYP2D6 poor metabolizers (CYP2D6*4/*4 genotype), and for measurement of endoxifen blood level in those women who are on the drug.
AmpliChipTM CYP450 is a microarray chip which contains millions of tiny DNA molecules, providing comprehensive coverage of gene variations that play a role in the metabolism of approximately 25% of all prescription drugs. The AmpliChipTM CYP450 test is intended to be an aid for physicians in individualizing treatment doses for patients receiving therapeutics metabolized through these enzymes.
The clinical data collected would examine if these individuals, as well as those treated with CYP2D6 inhibiting drugs such as paroxetine and fluoxetine, have higher cancer relapse rates.
The study, combined with similar findings from other countries, and possibly integrated later on with an international network study, would be imperative for modifying treatment recommendations for breast cancer therapy. Specifically, if the US and Italian findings are confirmed, it might be advisable to switch the 5-year follow-up treatment for breast cancer patients with ER positive primary tumors who are CYP2D6 poor metabolizers from tamoxifen to an aromatase inhibitor drug such as letrozole.
|Study Type :||Observational|
|Estimated Enrollment :||500 participants|
|Official Title:||CYP2D6 Genotyping by AmpliChipTM CYP450 for Tamoxifen-Treated Breast Cancer Patients|
|Study Start Date :||December 2008|
|Estimated Primary Completion Date :||December 2011|
Women diagnosed with receptor positive breast cancer, treated with Tamoxifen
|Other: There is no intervention - this is an observational study|
- Tamoxifen efficacy for avoiding breast cancer relapse in relation to CYP2D6 genotype
- Prevalence of CYP2D6 poor metabolizers genotype in Israeli female population treated with Tamoxifen
Biospecimen Retention: Samples With DNA
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00815555
|Contact: Matitiahu Berkovitch, Profemail@example.com|
|Clinical Pharmacology Unit - Assaf Harofeh Medical Center||Recruiting|
|Zerifin, Israel, 70300|
|Contact: Matitiahu Berkovitch, Prof 972-57-345152 firstname.lastname@example.org|