Breast CancerNCT00873366
Breath Test for Women Receiving Tamoxifen in the Prevention or Treatment of Breast Cancer
An observational study of Breast Cancer, run by Mayo Clinic at 2 sites in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 120 years, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- dextromethorphan hydrobromide, tamoxifen citrate and high performance liquid chromatography
- Type of treatment
- Surgery or procedure
- How many people
- 92 participants
- Where
- 2 sitesUnited States
- Study dates
- May 2009to 23 Sep 2015
- Phase
- Observational
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 120 years
- Women only
- No healthy volunteers
- Adult, Older adult
Study population: Female breast cancer
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)
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Mayo Clinic
Rochester, Minnesota, 55905
Mayo Clinic in Arizona
Scottsdale, Arizona
About this study
Official title: ¹³C - Dextromethorphan (DM) Breath Test for Determination of CYP2D6 Enzyme Activity in Patients Receiving Tamoxifen
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.
Read the detailed description
OBJECTIVES:
- To assess the operating characteristics of the ¹³C-dextromethorphan (^13 C-DM) breath test in identifying women with breast cancer (or at high risk) who are CYP2D6-genotypic poor metabolizers.
- To examine the correlation between CYP2D6 enzyme activity (as measured by the breath test) and plasma endoxifen (and 4-hydroxyTAM) levels in patients who carry one or more CYP2D6 functional alleles.
- To examine the change in CYP2D6 enzyme activity (as measured by the ¹³C-DM breath test), in patients who start a CYP2D6 inhibitor while taking tamoxifen.
- To determine whether CYP2D6 enzyme activity (as measured by the breath test) changes over time (either as a consequence of drug-induced inhibition or other).
- To measure genetic variation in additional genes that are later identified to affect the metabolism, uptake, or distribution of tamoxifen (e.g., SULT1A1, UGT).
OUTLINE: Patients receive tamoxifen citrate for 6 months. ^13C-dextromethorphan breath tests are conducted at baseline and periodically during the 6 months.
13C-dextromethorphan breath test: Patients receive oral Alka-Seltzer® Gold (ASG; citric acid, potassium bicarbonate, and sodium bicarbonate) in water, then, 15 minutes later, another ASG dose and oral ¹³C-dextromethorphan. Patients breathe into a bag 1-2 times, and the is bag sealed. ¹³CO_2 levels in the bags are measured.
Blood samples are collected at baseline and periodically for pharmacogenetic and pharmacokinetic studies by reverse phase HPLC with fluorescence detection.
After completion of study therapy, patients are followed annually for 5 years.
- Conditions
- Breast Cancer
- Being tested
- dextromethorphan hydrobromide, tamoxifen citrate, high performance liquid chromatography, laboratory biomarker analysis, pharmacogenomic studies
- Keywords
- stage I breast cancer, stage II breast cancer, stage IIIA breast cancer, stage IIIB breast cancer, stage IIIC breast cancer
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
dextromethorphan hydrobromideDrug
tamoxifen citrateDrug
high performance liquid chromatographyOther
laboratory biomarker analysisOther
pharmacogenomic studiesOther
fluorescence imagingProcedure or surgery
What is being measured
The primary outcome is the main question the study is designed to answer.
Operating Characteristics of the ¹³C-dextromethorphan (13C-DM) Breath Test in Identifying Those Who Are CYP2D6 Genotypic Poor Metabolizers
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.
Measured: Baseline
Secondary outcomes (15)
Spearman's Rank Correlation Coefficient Between CYP2D6 Genotype and ¹³Cdextromethorphan Breath Test (DM-BT)
Spearman rank order correlation coefficients were used to assess the strength of the association between CYP2D6 genotype activity score and DM-BT values.
Measured: Baseline, 3 month and 6 month
Spearman's Rank Correlation Coefficient Between CYP2D6 Activity Score and Endoxifen Steady State Concentrations (Endx Css)
Spearman rank order correlation coefficients were used to assess the strength of the association between CYP2D6 genotype activity score and Endx Css
Measured: 3 Month and 6 Month
Spearman's Rank Correlation Coefficient Between CYP2D6 Activity Score and Endoxifen/N-desmethyl-tamoxifen (Endx/NDMT) Ratio
Spearman rank order correlation coefficients were used to assess the strength of the association between CYP2D6 genotype activity score and Endx/NDMT ratio
Measured: 3 Month and 6 Month
Spearman's Rank Correlation Coefficient Between Baseline DM-BT and 3 Month Endoxifen Steady State Concentrations
Spearman rank order correlation coefficients were used to assess the strength of the association between baseline ¹³Cdextromethorphan breath test (DM-BT) and Endoxifen steady state concentrations (Endx Css)
Measured: Baseline, 3 month
Spearman's Rank Correlation Coefficient Between Baseline DM-BT and 3 Month Endoxifen/N-desmethyl-tamoxifen (Endx/NDMT) Ratio
Spearman rank order correlation coefficients were used to assess the strength of the association between baseline ¹³Cdextromethorphan breath test (DM-BT) and Endoxifen/N-desmethyl-tamoxifen (Endx/NDMT) Ratio
Measured: Baseline, 3 month
Spearman's Rank Correlation Coefficient Between 3 Month DM-BT and 3 Month Endoxifen Steady State Concentrations
Spearman rank order correlation coefficients were used to assess the strength of the association between baseline ¹³Cdextromethorphan breath test (DM-BT) and Endoxifen steady state concentrations (Endx Css)
Measured: 3 month
Spearman's Rank Correlation Coefficient Between 6 Month DM-BT and 6 Month Endoxifen Steady State Concentrations
Spearman rank order correlation coefficients were used to assess the strength of the association between baseline ¹³Cdextromethorphan breath test (DM-BT) and Endoxifen steady state concentrations (Endx Css)
Measured: 6 month
Median of 3 Month Tamoxifen Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
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 median of 3 month Tamoxifen steady state plasma concentrations for each CYP2D6 phenotype group are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 3 Month
Median of 6 Month Tamoxifen Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
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 median of 6 month Tamoxifen steady state plasma concentrations for each CYP2D6 phenotype group are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 6 Month
Median of 3 Month N-desmethyl-tamoxifen (NDMT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
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 median of 3 month NDMT steady state plasma concentrations for each CYP2D6 phenotype group are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 3 Month
Median of 6 Month N-desmethyl-tamoxifen (NDMT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
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 median of 6 month NDMT steady state plasma concentrations for each CYP2D6 phenotype group are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 6 Month
Median of 3 Month 4-hydroxy-tamoxifen (4HT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
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 median of 3 month 4HT steady state plasma concentrations for each CYP2D6 phenotype group are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 3 Month
Median of 6 Month 4-hydroxy-tamoxifen (4HT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
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 median of 6 month 4HT steady state plasma concentrations for each CYP2D6 phenotype group are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 6 Month
Median of 3 Month Endoxifen Steady State Concentrations (Endx Css) According to CYP2D6 Phenotype Group and Activity Score
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 median of 3 month Endx Css for each CYP2D6 phenotype group and the corresponding activity score are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 3 Month
Median of 6 Month Endoxifen Steady State Concentrations (Endx Css) According to CYP2D6 Phenotype Group and Activity Score
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 median of 6 month Endx Css for each CYP2D6 phenotype group and the corresponding activity score are summarized below. Refer to Outcome Measure 1 Data Table for details on the combination of genotype for each participant that are defined for each CYP2D6 phenotype group.
Measured: 6 Month
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Apr 2009 (estimated)
- Study startMay 2009
- Primary completion23 Sep 2015
- Study completion23 Sep 2015
Why it stopped: Funding issues
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by Mayo ClinicThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 92 participants (actual)
Sponsor and investigators
- Lead sponsor
- Mayo Clinic
- Sponsor type
- University, hospital or other
- Collaborators
- National Cancer Institute (NCI)
- Responsible party
- Sponsor
- Investigators
- Matthew P. Goetz, M.D., Study chair, Mayo ClinicDonald W. Northfelt, M.D., Principal investigator, Mayo Clinic
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00873366
- Sponsor's protocol ID
- MC083C
- Other IDs
- P30CA015083, MC083C, 08-007073
- Status last verified
- May 2017
- First submitted
- 31 Mar 2009
- Last updated
- 23 Jan 2018
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 23 Jan 2018. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- ¹³C - Dextromethorphan (DM) Breath Test for Determination of CYP2D6 Enzyme Activity in Patients Receiving Tamoxifen
- ClinicalTrials.gov ID
- NCT00873366
- Acronym / sponsor ID
- MC083C
- Conditions
- Breast Cancer
- Keywords
- stage I breast cancer, stage II breast cancer, stage IIIA breast cancer, stage IIIB breast cancer, stage IIIC breast cancer
- Study type
- Observational
- Recruitment status
- TerminatedReason stopped: Funding issues
- Enrolment
- 92 participants (actual)
- Lead sponsor
- Mayo ClinicUniversity, hospital or other
- Collaborators
- National Cancer Institute (NCI)
- Study start
- May 2009
- Primary completion
- 23 Sep 2015 (actual)
- Study completion
- 23 Sep 2015 (actual)
- First posted
- 1 Apr 2009 (estimated)
- Results
- Posted 23 Jan 2018
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
OBJECTIVES:
- To assess the operating characteristics of the ¹³C-dextromethorphan (^13 C-DM) breath test in identifying women with breast cancer (or at high risk) who are CYP2D6-genotypic poor metabolizers.
- To examine the correlation between CYP2D6 enzyme activity (as measured by the breath test) and plasma endoxifen (and 4-hydroxyTAM) levels in patients who carry one or more CYP2D6 functional alleles.
- To examine the change in CYP2D6 enzyme activity (as measured by the ¹³C-DM breath test), in patients who start a CYP2D6 inhibitor while taking tamoxifen.
- To determine whether CYP2D6 enzyme activity (as measured by the breath test) changes over time (either as a consequence of drug-induced inhibition or other).
- To measure genetic variation in additional genes that are later identified to affect the metabolism, uptake, or distribution of tamoxifen (e.g., SULT1A1, UGT).
OUTLINE: Patients receive tamoxifen citrate for 6 months. ^13C-dextromethorphan breath tests are conducted at baseline and periodically during the 6 months.
13C-dextromethorphan breath test: Patients receive oral Alka-Seltzer® Gold (ASG; citric acid, potassium bicarbonate, and sodium bicarbonate) in water, then, 15 minutes later, another ASG dose and oral ¹³C-dextromethorphan. Patients breathe into a bag 1-2 times, and the is bag sealed. ¹³CO_2 levels in the bags are measured.
Blood samples are collected at baseline and periodically for pharmacogenetic and pharmacokinetic studies by reverse phase HPLC with fluorescence detection.
After completion of study therapy, patients are followed annually for 5 years.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 to 120 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Female breast cancer
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| dextromethorphan hydrobromide | Drug | – |
| tamoxifen citrate | Drug | – |
| high performance liquid chromatography | Other | – |
| laboratory biomarker analysis | Other | – |
| pharmacogenomic studies | Other | – |
| pharmacological study | Other | – |
| fluorescence imaging | Procedure or surgery | – |
Primary outcome
Operating Characteristics of the ¹³C-dextromethorphan (13C-DM) Breath Test in Identifying Those Who Are CYP2D6 Genotypic Poor Metabolizers
Time frame: Baseline
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.
15 secondary outcomes
Spearman's Rank Correlation Coefficient Between CYP2D6 Genotype and ¹³Cdextromethorphan Breath Test (DM-BT)
Time frame: Baseline, 3 month and 6 month
Spearman's Rank Correlation Coefficient Between CYP2D6 Activity Score and Endoxifen Steady State Concentrations (Endx Css)
Time frame: 3 Month and 6 Month
Spearman's Rank Correlation Coefficient Between CYP2D6 Activity Score and Endoxifen/N-desmethyl-tamoxifen (Endx/NDMT) Ratio
Time frame: 3 Month and 6 Month
Spearman's Rank Correlation Coefficient Between Baseline DM-BT and 3 Month Endoxifen Steady State Concentrations
Time frame: Baseline, 3 month
Spearman's Rank Correlation Coefficient Between Baseline DM-BT and 3 Month Endoxifen/N-desmethyl-tamoxifen (Endx/NDMT) Ratio
Time frame: Baseline, 3 month
Spearman's Rank Correlation Coefficient Between 3 Month DM-BT and 3 Month Endoxifen Steady State Concentrations
Time frame: 3 month
Spearman's Rank Correlation Coefficient Between 6 Month DM-BT and 6 Month Endoxifen Steady State Concentrations
Time frame: 6 month
Median of 3 Month Tamoxifen Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
Time frame: 3 Month
Median of 6 Month Tamoxifen Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
Time frame: 6 Month
Median of 3 Month N-desmethyl-tamoxifen (NDMT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
Time frame: 3 Month
Median of 6 Month N-desmethyl-tamoxifen (NDMT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
Time frame: 6 Month
Median of 3 Month 4-hydroxy-tamoxifen (4HT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
Time frame: 3 Month
Median of 6 Month 4-hydroxy-tamoxifen (4HT) Steady State Plasma Concentrations According to CYP2D6 Phenotype Group
Time frame: 6 Month
Median of 3 Month Endoxifen Steady State Concentrations (Endx Css) According to CYP2D6 Phenotype Group and Activity Score
Time frame: 3 Month
Median of 6 Month Endoxifen Steady State Concentrations (Endx Css) According to CYP2D6 Phenotype Group and Activity Score
Time frame: 6 Month
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Jan 2018.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Matthew P. Goetz, M.D. study chair
Mayo Clinic
Donald W. Northfelt, M.D. principal investigator
Mayo Clinic
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Breast Cancer, run by Mayo Clinic at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 23 Jan 2018. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 23 Jan 2018). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Operating Characteristics of the ¹³C-dextromethorphan (13C-DM) Breath Test in Identifying Those Who Are CYP2D6 Genotypic Poor Metabolizers (time frame: Baseline). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Jan 2018.