An observational study in Breast Cancer, Depression and Hot Flashes, sponsored by Mayo Clinic. Completed at 6 sites in United States. Open to participants aged 18 Years to 120 Years. Per ClinicalTrials.gov, last updated 2025-02-14.
Sponsored by Mayo Clinic · Observational
RATIONALE: Studying samples of blood in the laboratory from patients receiving tamoxifen may help doctors learn more about the effects of other drugs on the level of tamoxifen in the blood.
PURPOSE: This clinical trial is studying levels of tamoxifen in the blood of women with breast cancer and in women at high risk of breast cancer who are receiving tamoxifen together with venlafaxine, citalopram, escitalopram, gabapentin, or sertraline.
OBJECTIVES:
OUTLINE: This is a multicenter study.
Patients receive oral tamoxifen citrate and concurrent selective serotonin reuptake inhibitor (SSRI)/serotonin-norepinephrine reuptake inhibitor (SNRI) therapy comprising oral venlafaxine, citalopram hydrobromide, escitalopram oxalate, sertraline hydrochloride, or gabapentin for 8-24 weeks. Treatment continues in the absence of disease progression.
Blood samples are obtained at baseline and after completion of study therapy. Samples are evaluated by pharmacokinetic analysis to determine the effects of SSRI/SNRI study drugs on plasma concentrations of tamoxifen and its metabolites. Plasma levels of tamoxifen citrate, N-desmethyl tamoxifen, 4-OH tamoxifen, and endoxifen are measured using reverse phase high performance liquid chromatography. Blood samples are also analyzed by CYP2D6 genotyping to test for CYP2D6 gene variation (i.e., *3, *4, *6, *10, *17, and *41) in genes that encode tamoxifen-metabolizing enzymes. Additional CYP2D6 alleles, including gene duplication and gene deletion (*5) are assessed.
12,544 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.
This study's enrollment of 88 is below the median of 184 across 2,642 observational studies indexed under Breast Neoplasms.
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PATIENT CHARACTERISTICS:
PRIOR CONCURRENT THERAPY:
Exclusion Criteria:
Known to be a CYP2D6 poor metabolizer (defined as homozygous for one of the following CYP2D6 null alleles: *3, *4, *5, *6).
Percent change in plasma concentrations of 4-hydroxy tamoxifen and of endoxifen after ≥ 8 weeks of concurrent administration of tamoxifen citrate and a CYP2D6 inhibitor
Time frame: Between 8-16 weeks
This study is completed, as verified in Aug 2024. You cannot join it, but the record below documents what was studied.
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