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Molecular Analyses to Predict Pathways of Endocrine Resistance Following Short Term Neoadjuvant Endocrine Treatment in Patients With Hormone Receptor-Positive HER2-negative Breast Cancer

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)

Status
Recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06361940
Acronym
MAPPER
Enrollment
100
Registered
2024-04-12
Start date
2024-09-30
Completion date
2029-12-31
Last updated
2025-10-14

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast Cancer

Keywords

hormone receptor-positive, HER2-negative, endocrine therapy, neoadjuvant, anastrozole, letrozole, exemestane, tamoxifen

Brief summary

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.

Interventions

DRUGAromatase 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.

Sponsors

Medical College of Wisconsin
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

1. Unilateral diagnostic breast mammogram and ultrasound within 60 days of enrollment. 2. Pathologically proven diagnosis of invasive breast cancer, clinical stage I or II. 3. Patients must be clinically lymph node negative. Lymph node negativity must be confirmed by clinical exam and/or ultrasound imaging. 4. The patient must be female. 5. Age ≥18 years. 6. 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. 7. Human epidermal growth factor receptor 2 (HER2) /neu must be negative by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH). 8. Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2. 9. Bilateral breast cancer and/or multifocal, multicentric disease is allowed. 10. 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. 11. The patient must qualify for endocrine treatment (treatment of choice), per the treating medical oncologist. 12. The patient must provide study-specific informed consent prior to study entry. 13. 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. 14. 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. 15. 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.). 16. 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

1. American Joint Committee on Cancer (AJCC) clinical T4, N1-3 or M1, breast cancer. 2. Synchronous non-breast malignancy (exceptions include non-melanomatous skin cancer, carcinoma in situ of the cervix). 3. Purely noninvasive breast cancer (i.e., ductal carcinoma in situ, lobular carcinoma in situ). 4. Men with breast cancer. Male breast cancer is a rare event and it is unclear if neoadjuvant endocrine treatment approach is safe in men. 5. Medical, psychiatric or other condition that would prevent the patient from receiving the protocol therapy or providing informed consent. 6. Pregnant or lactating women are ineligible.

Design outcomes

Primary

MeasureTime frameDescription
Change from baseline in the number of subjects with increased HER-1 receptor tyrosine kinases protein expression in tumors.Time of surgeryPathologists 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 of surgeryPathologists 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 of surgeryPathologists 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 of surgeryPathologists 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.

Countries

United States

Contacts

Primary ContactMedical College of Wisconsin Cancer Center Clinical Trials Office
cccto@mcw.edu866-680-0505

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026