NCT06361940 · Medical College of Wisconsin
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)
What this study is about
This is an exploratory phase II interventional study that initiates standard-of-care anti-estrogen treatment preoperatively for 4-12 weeks (+/- 2 weeks).
View original scientific description
This is an exploratory phase II interventional study that initiates standard-of-care anti-estrogen treatment preoperatively for 4-12 weeks (+/- 2 weeks).
Interventions
DRUG
Aromatase inhibitors or tamoxifen
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.
Primary outcome measures
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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.
- 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.
Exclusion criteria
- 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.
Where
- Milwaukee, Wisconsin
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Oct 14, 2025 · Source of record for eligibility and locations