Breast CancerPhase 2MAPPERNCT06361940
Molecular Analyses to Predict Pathways of Endocrine Resistance Following Short Term Neoadjuvant Endocrine Treatment in Patients With Hormone Receptor-Positive HER2-negative Breast Cancer
A Phase 2 study testing Aromatase inhibitors or tamoxifen in people with Breast Cancer, run by Medical College of Wisconsin at 1 site in United States.
Trial summary
This is an exploratory phase II interventional study that initiates standard-of-care anti-estrogen treatment preoperatively for 4-12 weeks (+/- 2 weeks). Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- Aromatase inhibitors or tamoxifen
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 185 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Sep 2024to Dec 2028
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
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 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Unilateral diagnostic breast mammogram and ultrasound within 60 days of enrollment.
- Pathologically proven diagnosis of invasive breast cancer, clinical stage I or II.
- Patients must be clinically lymph node negative. Lymph node negativity must be confirmed by clinical exam and/or ultrasound imaging.
- The patient must be female.
- Age ≥18 years.
- Estrogen and/or progesterone receptor positive tumor defined ≥1% positively staining cells by immunohistochemistry, according to the current American Society of Clinical Oncology/College of American Pathologists guidelines.
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- Human epidermal growth factor receptor 2 (HER2) /neu must be negative by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH).
- Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2.
- Bilateral breast cancer and/or multifocal, multicentric disease is allowed.
- Appropriate pretreatment evaluations for protocol entry, including no clinical evidence for distant metastases, based upon the following minimum diagnostic workup: history/physical examination, including breast exam (inspection and palpation of the breasts), clinically negative axillary lymph nodes, within 28 days prior to study entry.
- The patient must qualify for endocrine treatment (treatment of choice), per the treating medical oncologist.
- The patient must provide study-specific informed consent prior to study entry.
- Patients with a prior history of breast cancer will be considered eligible, if they have completed all treatment (including endocrine therapy) more than two years prior to registration.
- Patients must not have had a prior treatment for this breast cancer or for any malignancy diagnosed or treated within the past two years, with the exception of non-melanomatous skin cancer, carcinoma in situ of the cervix.
- Women of childbearing age will be advised to use adequate methods of contraception. Adequate methods of contraception for premenopausal women include barrier methods and/or non-hormonal methods (Intrauterine devices etc.).
- Strong cytochrome P450 2D6 (CYP2D6) inhibitors will be prohibited with tamoxifen, as it can decrease the efficacy of tamoxifen. There are no known strong interactions with aromatase inhibitors.
Who cannot join
- American Joint Committee on Cancer (AJCC) clinical T4, N1-3 or M1, breast cancer.
- Synchronous non-breast malignancy (exceptions include non-melanomatous skin cancer, carcinoma in situ of the cervix).
- Purely noninvasive breast cancer (i.e., ductal carcinoma in situ, lobular carcinoma in situ).
- Men with breast cancer. Male breast cancer is a rare event and it is unclear if neoadjuvant endocrine treatment approach is safe in men.
- Medical, psychiatric or other condition that would prevent the patient from receiving the protocol therapy or providing informed consent.
- Pregnant or lactating women are ineligible.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Medical College of Wisconsin Cancer Center Clinical Trials Office contact
United States1 site, 1 recruiting
- Recruiting
Froedtert Hospital and the Medical College of Wisconsin
Milwaukee, Wisconsin, 53226
Lubna N Chaudhary, MD, lchaudhary@mcw.edu
About this study
Official title: Molecular Analyses to Predict Pathways of Endocrine Resistance Following Short Term Neoadjuvant Endocrine Treatment in Patients With Hormone Receptor-Positive HER2-negative Breast Cancer (MAPPER)
This is an exploratory phase II interventional study that initiates standard-of-care anti-estrogen treatment preoperatively for 4-12 weeks (+/- 2 weeks).
Read the detailed description
Patients with HR+ HER2- node-negative breast cancers generally undergo surgical resection upfront, followed by adjuvant chemotherapy, if needed, in addition to adjuvant endocrine therapy. Because endocrine therapy is primarily delivered in the postoperative setting, the ability to assess the tumor response to this treatment modality is lost and very difficult to assess. This study offers the unique opportunity to assess the responsiveness of breast tumors to endocrine therapy while the tumors are still in vivo by treating patients with endocrine therapy before surgery and assessing molecular changes with treatment. By comparing pre- and post-treatment levels of molecular markers with advanced omic analysis in individual tumors, the investigators expect to identify predictors of responsiveness to existing agents and identify new candidate therapeutic targets.
- Conditions
- Breast Cancer
- Being tested
- Aromatase inhibitors or tamoxifen
- Keywords
- hormone receptor-positive, HER2-negative, endocrine therapy, neoadjuvant, anastrozole, letrozole, exemestane, tamoxifen
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Aromatase inhibitors or tamoxifenDrug
Choice of endocrine therapy (aromatase inhibitors or tamoxifen) would be decided by medical oncologist, following a review of the patient's medical history and menstrual status.
| Study group | Role | What they receive |
|---|---|---|
| Standard-of-care Endocrine therapy | Experimental | Once enrolled, patients would be treated with the current standard-of-care endocrine therapy. Receives: Drug: Aromatase inhibitors or tamoxifen |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from baseline in the number of subjects with increased HER-1 receptor tyrosine kinases protein expression in tumors.
Pathologists will use immunohistochemistry (IHC) to determine the average count of tumor protein expression. IHC is reported categorically as 0,1, 2 or 3. Any increase between these categories is considered increase.
Measured: Time of surgery
Change from baseline in the number of subjects with increased HER-2 receptor tyrosine kinases protein expression in tumors.
Pathologists will use immunohistochemistry to determine the average count of tumor protein expression. IHC is reported categorically as 0,1,2 or 3. Any increase between these categories is considered increase.
Measured: Time of surgery
Change from baseline in the number of subjects with increased HER-3 receptor tyrosine kinases protein expression in tumors.
Pathologists will use immunohistochemistry to determine the average count of tumor protein expression. IHC is reported categorically as 0,1,2 or 3. Any increase between these categories is considered increase.
Measured: Time of surgery
Change from baseline in the number of subjects with increased HER-4 receptor tyrosine kinases protein expression in tumors.
Pathologists will use immunohistochemistry to determine the average count of tumor protein expression. IHC is reported categorically as 0,1,2 or 3. Any increase between these categories is considered increase.
Measured: Time of surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Apr 2024
- Study start30 Sep 2024
- Primary completionSep 2028 (estimated)
- Study completionDec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by Medical College of WisconsinThe 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
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 185 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medical College of Wisconsin
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Lubna Chaudhary, Medical College of Wisconsin
- Investigators
- Lubna N Chaudhary, MD, Principal investigator, Medical College of Wisconsin
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06361940
- Sponsor's protocol ID
- PRO00052561
- Acronym
- MAPPER
- Status last verified
- Oct 2026
- First submitted
- 8 Apr 2024
- Last updated
- 20 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Molecular Analyses to Predict Pathways of Endocrine Resistance Following Short Term Neoadjuvant Endocrine Treatment in Patients With Hormone Receptor-Positive HER2-negative Breast Cancer (MAPPER)
- ClinicalTrials.gov ID
- NCT06361940
- Acronym / sponsor ID
- MAPPER / PRO00052561
- Conditions
- Breast Cancer
- Keywords
- hormone receptor-positive, HER2-negative, endocrine therapy, neoadjuvant, anastrozole, letrozole, exemestane, tamoxifen
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 185 participants (estimated)
- Lead sponsor
- Medical College of WisconsinUniversity, hospital or other
- Study start
- 30 Sep 2024 (actual)
- Primary completion
- Sep 2028 (estimated)
- Study completion
- Dec 2028 (estimated)
- First posted
- 12 Apr 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is an exploratory phase II interventional study that initiates standard-of-care anti-estrogen treatment preoperatively for 4-12 weeks (+/- 2 weeks).
Detailed description
Patients with HR+ HER2- node-negative breast cancers generally undergo surgical resection upfront, followed by adjuvant chemotherapy, if needed, in addition to adjuvant endocrine therapy. Because endocrine therapy is primarily delivered in the postoperative setting, the ability to assess the tumor response to this treatment modality is lost and very difficult to assess. This study offers the unique opportunity to assess the responsiveness of breast tumors to endocrine therapy while the tumors are still in vivo by treating patients with endocrine therapy before surgery and assessing molecular changes with treatment. By comparing pre- and post-treatment levels of molecular markers with advanced omic analysis in individual tumors, the investigators expect to identify predictors of responsiveness to existing agents and identify new candidate therapeutic targets.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Standard-of-care Endocrine therapy | Experimental | Drug: Aromatase inhibitors or tamoxifenOnce enrolled, patients would be treated with the current standard-of-care endocrine therapy. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (16 listed)
- Unilateral diagnostic breast mammogram and ultrasound within 60 days of enrollment.
- Pathologically proven diagnosis of invasive breast cancer, clinical stage I or II.
- Patients must be clinically lymph node negative. Lymph node negativity must be confirmed by clinical exam and/or ultrasound imaging.
- The patient must be female.
- Age ≥18 years.
Key exclusion criteria (6 listed)
- American Joint Committee on Cancer (AJCC) clinical T4, N1-3 or M1, breast cancer.
- Synchronous non-breast malignancy (exceptions include non-melanomatous skin cancer, carcinoma in situ of the cervix).
- Purely noninvasive breast cancer (i.e., ductal carcinoma in situ, lobular carcinoma in situ).
- Men with breast cancer. Male breast cancer is a rare event and it is unclear if neoadjuvant endocrine treatment approach is safe in men.
- Medical, psychiatric or other condition that would prevent the patient from receiving the protocol therapy or providing informed consent.
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 |
|---|---|---|
| Aromatase inhibitors or tamoxifenChoice of endocrine therapy (aromatase inhibitors or tamoxifen) would be decided by medical oncologist, following a review of the patient's medical history and menstrual status. | Drug | Standard-of-care Endocrine therapy |
Primary outcome
Change from baseline in the number of subjects with increased HER-1 receptor tyrosine kinases protein expression in tumors.
Time frame: Time of surgery
Pathologists will use immunohistochemistry (IHC) to determine the average count of tumor protein expression. IHC is reported categorically as 0,1, 2 or 3. Any increase between these categories is considered increase.
Change from baseline in the number of subjects with increased HER-2 receptor tyrosine kinases protein expression in tumors.
Time frame: Time of surgery
Pathologists will use immunohistochemistry to determine the average count of tumor protein expression. IHC is reported categorically as 0,1,2 or 3. Any increase between these categories is considered increase.
Change from baseline in the number of subjects with increased HER-3 receptor tyrosine kinases protein expression in tumors.
Time frame: Time of surgery
Pathologists will use immunohistochemistry to determine the average count of tumor protein expression. IHC is reported categorically as 0,1,2 or 3. Any increase between these categories is considered increase.
Change from baseline in the number of subjects with increased HER-4 receptor tyrosine kinases protein expression in tumors.
Time frame: Time of surgery
Pathologists will use immunohistochemistry to determine the average count of tumor protein expression. IHC is reported categorically as 0,1,2 or 3. Any increase between these categories is considered increase.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Oct 2026.
- Individual participant dataSharing planned: No
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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.
Medical College of Wisconsin Cancer Center Clinical Trials Office contact
Lubna N Chaudhary, MD principal investigator
Medical College of Wisconsin
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Aromatase inhibitors or tamoxifen in people with Breast Cancer, run by Medical College of Wisconsin at 1 site 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?
The sponsor lists 16 inclusion and 6 exclusion criteria. 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: looking for participants now, as of the sponsor's last update on 20 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site 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.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Medical College of Wisconsin Cancer Center Clinical Trials Office (866-680-0505 ext. 8900, cccto@mcw.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change from baseline in the number of subjects with increased HER-1 receptor tyrosine kinases protein expression in tumors. (time frame: Time of surgery). The study lists 4 primary outcomes in all. 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 20 Oct 2026.