NCT06184750

Brief Summary

This phase II trial evaluates response-guided low-dose tamoxifen for reducing breast density in women who are at higher than average risk for breast cancer. Increasing breast density is a well established risk factor for breast cancer. Tamoxifen is a selective estrogen receptor modulator. It works by blocking the effects of the hormone estrogen in the breast. Tamoxifen has been shown to reduce breast density, even at reduced dosages, and is approved for the prevention of breast cancer.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
200

participants targeted

Target at P75+ for phase_2

Timeline
29mo left

Started Sep 2024

Typical duration for phase_2

Geographic Reach
1 country

11 active sites

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress40%
Sep 2024Sep 2028

First Submitted

Initial submission to the registry

December 27, 2023

Completed
1 day until next milestone

First Posted

Study publicly available on registry

December 28, 2023

Completed
9 months until next milestone

Study Start

First participant enrolled

September 27, 2024

Completed
3.5 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

March 31, 2028

Expected
6 months until next milestone

Study Completion

Last participant's last visit for all outcomes

September 30, 2028

Last Updated

May 4, 2026

Status Verified

March 1, 2026

Enrollment Period

3.5 years

First QC Date

December 27, 2023

Last Update Submit

May 1, 2026

Conditions

Outcome Measures

Primary Outcomes (1)

  • Proportion of women who have a response at any time point

    Tamoxifen response is defined as absolute dense area reduction (aDAR) of \>= 10% on mammogram compared to baseline mammogram. A one sample exact binomial test for one proportion will be used, and the exact two-sided p-value will be reported. Response rate for the entire study population, as well as for the group of women who were dose-escalated, will be estimated and reported with the corresponding 95% confidence interval. Absolute and relative changes in dense area will be estimated using descriptive statistics (e.g., mean and standard deviation, or median and interquartile range), and, as a sensitivity analysis, a paired t-test or the signed rank test will be used to determine whether there was a reduction in dense area. Similar descriptive statistics will be performed in each dose sequence group for both the response rate and dense area changes.

    At 6, 12, and 18 months

Secondary Outcomes (5)

  • Plasma levels of major tamoxifen (TAM) metabolites

    At 6, 12, and 18 months

  • Longitudinal change in serum biomarkers of tamoxifen response

    From baseline up to 18 months

  • Baseline dense area

    Up to 18 months

  • Patient-reported symptoms

    At baseline, 6, 12, and 18 months

  • Adherence to final tamoxifen dose

    Up to 18 months

Other Outcomes (3)

  • Breast tissue-based biomarkers

    At 6 months

  • Single nucleotide polymorphisms (SNPs)

    Up to 18 months

  • Change in breast cancer risk estimates

    From baseline to 18 months

Study Arms (1)

Prevention (tamoxifen)

EXPERIMENTAL

Participants receive tamoxifen 5mg PO QD for 6 months. Participants with aDAR \>= 10% on mammogram at 6 months continue receiving tamoxifen 5mg PO QD for 12 months. Participants with aDAR \< 10% at 6 months are escalated to receive tamoxifen 10mg PO QD for 6 months. Participants with aDAR \>= 10% after 6 months of tamoxifen 10mg continue receiving tamoxifen 10 mg PO QD for 6 months. Participants with aDAR \< 10% after 6 months of tamoxifen 10mg are given the option of continuing tamoxifen 10mg or escalating to receive tamoxifen 20mg PO QD for 6 months. Participants undergo mammography and collection of blood samples at screening and on study. Participants may optionally undergo biopsy at screening and on study.

Procedure: Biopsy ProcedureProcedure: Biospecimen CollectionProcedure: MammographyOther: Questionnaire AdministrationDrug: Tamoxifen

Interventions

Undergo biopsy

Also known as: Biopsy, BIOPSY_TYPE, Bx
Prevention (tamoxifen)

Undergo collection of blood samples

Also known as: Biological Sample Collection, Biospecimen Collected, Specimen Collection
Prevention (tamoxifen)
MammographyPROCEDURE

Undergo mammography

Also known as: MG
Prevention (tamoxifen)

Ancillary studies

Prevention (tamoxifen)

Given PO

Also known as: TMX
Prevention (tamoxifen)

Eligibility Criteria

Age18 Years - 55 Years
Sexfemale
Healthy VolunteersNo
Age GroupsAdult (18-64)

You may qualify if:

  • Premenopausal women at the time of enrollment defined by any of the following:
  • Age under 50 years and regular menstruation (most recent period within the past 3 months)
  • Age under 50 years and continuous hormonal contraception use and at least one intact ovary
  • Women who are not postmenopausal based on serum hormone levels. Women with estradiol =\< 30 pg/mL, follicle-stimulating hormone (FSH) \>= 30 IU/mL are eligible
  • Women with any of the following:
  • A history of unilateral estrogen receptor (ER) positive ductal carcinoma in situ (DCIS) with local therapy completed (as determined by treating physician recommendation and patient acceptance) at least 1 month prior to study entry. (The untreated breast will be the study breast, for both imaging and optional biopsy)
  • Recent or prior lobular carcinoma in situ (LCIS), or any form of epithelial atypia, flat epithelial (FEA), atypical ductal hyperplasia (ADH), or atypical lobular hyperplasia (ALH)
  • Are risk eligible for preventive medication based on a five-year risk of 1.7% or greater, estimated with a validated model: the National Cancer Institute (NCI) Breast Cancer Risk Assessment Tool, Tyrer-Cusick, Breast Cancer Surveillance Consortium. If the Tyrer-Cuzick model is used a ten-year risk of 3.4% or greater is acceptable
  • Are tamoxifen-eligible by American Society of Clinical Oncology (ASCO) guidelines (\>= 2-fold increased risk compared to peer if age \>= 45 years, and \>= 4-fold increased risk if age \< 45 years)
  • A history of mantle radiotherapy
  • A moderate penetrance germline pathogenic variant
  • Participants ≥ 18 and ≤ 55 years old will be enrolled. Our trial objectives are not relevant to females under 18 years of age since breast cancer is extraordinarily rare in this age group, and there are no guidelines regarding use of tamoxifen in children, even if know to be at very high risk for breast cancer when older. Because no dosing or adverse event (AE) data are currently available on the use of tamoxifen in participants \< 18 years of age
  • Eastern Cooperative Oncology Group (ECOG) performance status must be =\< 2 (Karnofsky \>= 60%)
  • Human immunodeficiency virus (HIV)-infected patients are eligible to participate if they are on effective anti-retroviral therapy with undetectable viral load within the prior 6 months
  • Women with evidence of chronic hepatitis B virus (HBV) infection, are also eligible if the HBV viral load is undetectable; they may be on suppressive therapy, if indicated
  • +7 more criteria

You may not qualify if:

  • BIRADS breast density category A on most recent mammogram
  • History of selective estrogen receptor modulator (SERM) use within the past 5 years unless:
  • Use was less than 6 months duration in the past 5 years and not used in the 1 year prior to enrollment OR
  • Use was no greater than 2 months duration in the past 1 year and not used in the 6 months prior to enrollment
  • History of invasive breast cancer
  • Prior bilateral mastectomy or breast augmentation surgery including breast implants. Prior bilateral excisional surgical biopsy, mastopexy (breast lift) or mammoplasty (breast reduction) is allowed, as long as \> 1 year has passed since the procedure
  • Women with "mosaic mammographic screening views", i.e., whose larger breast size precludes being imaged within a single mammographic screening view
  • Current use of a strong CYP3A4 inducer or a strong CYP2D6 inhibitor unless willing and able to discontinue use and switch to an alternative medication for the duration of participation, under the advice of their physician. If the physician believes the current medication cannot be replaced, the participant will not be eligible
  • Current use of Warfarin
  • Planning to become pregnant within the next two years. Potential study participants will be questioned about this and excluded if they are planning pregnancy over the next 20 months
  • History of thromboembolism, pulmonary embolism, thrombotic stroke, arterial thrombosis of the extremity or deep vein thrombosis. A history of superficial thrombophlebitis is allowed
  • History of uterine cancer or atypical uterine hyperplasia with uterus intact
  • Participants may not be receiving any other investigational agents
  • History of allergic reactions attributed to compounds of similar chemical or biologic composition to tamoxifen
  • Uncontrolled intercurrent illness or psychiatric illness/social situations that would limit compliance with study requirements
  • +4 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (11)

University of Arizona Cancer Center - Prevention Research Clinic

Tucson, Arizona, 85719, United States

RECRUITING

Northwestern University

Chicago, Illinois, 60611, United States

RECRUITING

University of Illinois College of Medicine - Chicago

Chicago, Illinois, 60612, United States

RECRUITING

University of Kansas Cancer Center

Kansas City, Kansas, 66160, United States

RECRUITING

Brigham and Women's Hospital

Boston, Massachusetts, 02115, United States

RECRUITING

Dana-Farber Cancer Institute

Boston, Massachusetts, 02215, United States

RECRUITING

University of Michigan Rogel Cancer Center

Ann Arbor, Michigan, 48109, United States

RECRUITING

Washington University School of Medicine

St Louis, Missouri, 63110, United States

RECRUITING

Case Western Reserve University

Cleveland, Ohio, 44106, United States

RECRUITING

Medical University of South Carolina

Charleston, South Carolina, 29425, United States

RECRUITING

M D Anderson Cancer Center

Houston, Texas, 77030, United States

RECRUITING

MeSH Terms

Conditions

Carcinoma, Intraductal, NoninfiltratingBreast NeoplasmsBreast Carcinoma In Situ

Interventions

BiopsySpecimen HandlingTamoxifen

Condition Hierarchy (Ancestors)

AdenocarcinomaCarcinomaNeoplasms, Glandular and EpithelialNeoplasms by Histologic TypeNeoplasmsCarcinoma in SituNeoplasms, Ductal, Lobular, and MedullaryNeoplasms by SiteBreast DiseasesSkin DiseasesSkin and Connective Tissue Diseases

Intervention Hierarchy (Ancestors)

CytodiagnosisCytological TechniquesClinical Laboratory TechniquesDiagnostic Techniques and ProceduresDiagnosisDiagnostic Techniques, SurgicalSurgical Procedures, OperativeInvestigative TechniquesStilbenesBenzylidene CompoundsBenzene DerivativesHydrocarbons, AromaticHydrocarbons, CyclicHydrocarbonsOrganic Chemicals

Study Officials

  • Seema A Khan

    Northwestern University

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
phase 2
Allocation
NA
Masking
NONE
Purpose
PREVENTION
Intervention Model
SINGLE GROUP
Sponsor Type
NIH
Responsible Party
SPONSOR

Study Record Dates

First Submitted

December 27, 2023

First Posted

December 28, 2023

Study Start

September 27, 2024

Primary Completion (Estimated)

March 31, 2028

Study Completion (Estimated)

September 30, 2028

Last Updated

May 4, 2026

Record last verified: 2026-03

Data Sharing

IPD Sharing
Will share

"NCI is committed to sharing data in accordance with NIH policy. For more details on how clinical trial data is shared, access the link to the NIH data sharing policy page."

More information

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