Tamoxifen in Women With Breast Cancer and in Women at High-Risk of Breast Cancer Who Are Receiving Venlafaxine, Citalopram, Escitalopram, Gabapentin, or Sertraline

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

88 participants

Study Classification

OBSERVATIONAL

Study Start Date

2011-03-16

Study Completion Date

2014-05-27

Brief Summary

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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.

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Detailed Description

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OBJECTIVES:

* To examine the changes in the plasma concentrations of the hydroxylated metabolite, 4-hydroxy tamoxifen, and endoxifen in women with known or at high risk for developing breast cancer who are receiving selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor therapy comprising venlafaxine, citalopram hydrobromide, escitalopram oxalate, gabapentin, or sertraline hydrochloride for the treatment of hot flashes, depression, or any other medically indicated condition.
* To evaluate whether genetic variants known to affect the activity of CYP2D6, SULT1A1, and other drug metabolizing enzymes (e.g., UGT's) involved in the biotransformation of tamoxifen citrate affect the plasma concentrations of the hydroxylated metabolites, 4-hydroxy tamoxifen and endoxifen.

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.

Conditions

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Breast Cancer Depression Hot Flashes Psychosocial Effects of Cancer and Its Treatment

Study Design

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Observational Model Type

CASE_CONTROL

Study Time Perspective

CROSS_SECTIONAL

Interventions

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citalopram hydrobromide

Intervention Type DRUG

escitalopram oxalate

Intervention Type DRUG

gabapentin

Intervention Type DRUG

sertraline hydrochloride

Intervention Type DRUG

tamoxifen citrate

Intervention Type DRUG

venlafaxine

Intervention Type DRUG

molecular genetic technique

Intervention Type GENETIC

high performance liquid chromatography

Intervention Type OTHER

laboratory biomarker analysis

Intervention Type OTHER

pharmacological study

Intervention Type OTHER

adjuvant therapy

Intervention Type PROCEDURE

Eligibility Criteria

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Inclusion Criteria

* Prescribed tamoxifen either for the prevention or treatment of non-invasive or invasive breast cancer.
* Tamoxifen use \> 4 weeks without any breaks at a dose of 20 mg/day prior to registration
* to begin medical therapy with one of the following drugs: venlafaxine, citalopram, escitalopram, sertraline or gabapentin as determined by their physician
* Agree to continue tamoxifen during the proposed minimum study period of 8 weeks
* Willing to avoid known inhibitors of the CYP2D6 system for duration of study
* Ability to provide informed consent
* Willing to return to primary site of enrollment for follow-up
* Life expectancy \>= 16 weeks
* Agree to provide a blood specimen at the time of pre-treatment (baseline) and at follow-up

Exclusion Criteria

* Contraindication to the use of venlafaxine, citalopram, escitalopram, gabapentin or sertraline.
* Use of medications that are known to inhibit the CYP2D6 system within 3 weeks of registration. (see appendix II for list)
* Known to be a CYP2D6 poor metabolizer (defined as homozygous for one of the following CYP2D6 null alleles: \*3, \*4, \*5, \*6).

* Note: CYP2D6 genotyping is not required prior to enrollment; however, CYP2D6 genotyping will be performed at baseline and the treating physician will be notified of the results: all genotypic CYP2D6 PM will be replaced

Minimum Eligible Age

18 Years

Maximum Eligible Age

120 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No