Clinical trial · Observational
Breath Test for Women Receiving Tamoxifen in the Prevention or Treatment of Breast Cancer
¹³C - Dextromethorphan (DM) Breath Test for Determination of CYP2D6 Enzyme Activity in Patients Receiving Tamoxifen
NCT00873366CI-TRIAL-00031301terminatedResults postedClinicalTrials.gov clinicaltrialsProvenance
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Why stopped (as posted): Funding issues
Summary
Brief summary (as posted)
RATIONALE: A breath test that measures enzymes may be effective in identifying women in whom tamoxifen may not be effective. PURPOSE: This clinical trial is studying a breath test to see how well it works in women receiving tamoxifen for the prevention or treatment of breast cancer.
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Breast Cancer | Malignant Breast Neoplasm | CURATED_EXACT | 0.92 |
Interventions
Interventions (7)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| dextromethorphan hydrobromide | Drug | — | UNRESOLVED |
| fluorescence imaging | Procedure | — | UNRESOLVED |
| high performance liquid chromatography | Other | — | UNRESOLVED |
| laboratory biomarker analysis | Other | — | UNRESOLVED |
| pharmacogenomic studies | Other | — | UNRESOLVED |
| pharmacological study | Other | — | UNRESOLVED |
| tamoxifen citrate | Drug | Tamoxifen | ALIAS |
Design
Arms and outcomes
Arms (0)
[]Primary outcomes (1)
- measure
- Operating Characteristics of the ¹³C-dextromethorphan (13C-DM) Breath Test in Identifying Those Who Are CYP2D6 Genotypic Poor Metabolizers
- timeFrame
- Baseline
- description
- Participants were classified as having CYP2D6 decreased or non-decreased metabolism based on genotype and the co-prescription of inhibitors of the enzyme system. The specific phenotype, alleles and their associated activity score (AS) assessed were as follows: Ultrarapid metabolism (UM) or AS=2.0 (\*1XN or \*2XN), Extensive metabolism (EM) or AS=1.0 (\*1, \*2, and \*2A), Intermediate metabolism (IM) or AS=0.5 (\*9, \*10, \*17 and \*41), and Poor metabolism (PM) or AS=0.0 (3, \*4, \*5, \*7, \*8, \*11, and \*12). The distribution of CYP2D6 genotypes grouped by CYP2D6 metabolism phenotype for each participants are summarized below.
Secondary outcomes (15)
- measure
- Spearman's Rank Correlation Coefficient Between CYP2D6 Genotype and ¹³Cdextromethorphan Breath Test (DM-BT)
- timeFrame
- Baseline, 3 month and 6 month
- description
- Spearman rank order correlation coefficients were used to assess the strength of the association between CYP2D6 genotype activity score and DM-BT values.
Eligibility
Eligibility (as posted)
- Sex
- Female
- Minimum age
- 18 Years
- Maximum age
- 120 Years
Show eligibility criteria text
DISEASE CHARACTERISTICS: * Eligible to receive tamoxifen for 6 months for either the prevention or treatment of non-invasive or invasive, stage I-III breast cancer * CYP2D6 genotype known * Patients determined to be CYP2D6 poor metabolizers (by determination of a genotype test by their Mayo physician prior to study registration) are eligible to proceed with the initial breath test only * Hormone receptor status not specified PATIENT CHARACTERISTICS: * Menopausal status not specified * ECOG performance status 0-2 * Life expectancy \> 6 months * No known impaired hepatic activity defined as ≥ grade 3 AST, alkaline phosphatase, or total bilirubin * No pulmonary disease (e.g., asthma or other respiratory disease) associated with hypercapnia * No uncontrolled metabolic disease (e.g., diabetes in the presence of gastroparesis, uncontrolled congestive heart failure, or uncontrolled gastrointestinal disorders \[e.g., GERD\]) * No prior adverse reaction to dextromethorphan * No history of chronic liver disease (e.g., hepatitis B or hepatitis C, alcoholic liver disease, cirrhosis, or fibrotic disease) * Able and willing to fast overnight prior to the study session * Willing to return to Mayo Clinic for follow-up * Willing to provide biologic specimens PRIOR CONCURRENT THERAPY: * More than 24 hours since prior medications known to slow gastric emptying or gastrointestinal motility (e.g., alcohol, opioid analgesics, anticholinergics \[e.g., antihistamines\], and loperamide) * More than 4 weeks since prior and no concurrent CYP2D6 inhibitors or concurrent serotonin-reuptake inhibitors known to be potent CYP2D6 inhibitors (e.g.,paroxetine \[Paxil®\] and fluoxetine \[Prozac®\] * If mild to moderate inhibitors of CYP2D6 are medically necessary, patients may go back on after the 8-week time point * More than 4 weeks since prior and no concurrent monoamine-oxidase inhibitors (e.g., furazolidone, phenelzine, procarbazine, selegiline, and tranylcypromine)
References
Publications (0)
Data not yet available
No reference posted for this study.