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Study identifier: NCT05941520 Synced from ClinicalTrials.gov · July 28, 2026
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Acolbifene Versus Low Dose Tamoxifen for the Prevention of Breast Cancer in Premenopausal Women at High Risk for Development of Breast Cancer

Condition: Breast Atypical Hyperplasia · Breast Carcinoma · Breast Ductal Carcinoma In Situ  ·  Sponsor: National Cancer Institute (NCI)

PhasePhase 2
Planned participants80
Who can joinFemale, 35 Years to no upper limit
Healthy volunteersNo

About this study

This phase IIA trial compares the effect of acolbifene versus low dose tamoxifen in preventing breast cancer in premenopausal women at high risk for developing breast cancer. The usual approach for patients at increased risk for breast cancer is to undergo yearly breast magnetic resonance imaging or ultrasound in addition to yearly mammogram. Premenopausal women at very high lifetime risk for breast cancer (greater than 50%) can consider preventive removal (mastectomy) of both breasts. Premenopausal women age 35 or older with a prior diagnosis of atypical hyperplasia, lobular carcinoma in situ, or an estimated 10-year risk of greater than or equal to 3% or estimated 10-year risk of greater than or equal to 2-5 times that of the average woman (depending on age) may be advised to consider five years of standard dose tamoxifen. Standard dose tamoxifen is four times the dose used in this study. Estrogen can cause the development and growth of breast cancer cells. Acolbifene and tamoxifen blocks the use of estrogen by breast cells. This study may help researchers measure the effects of acolbifene and low dose tamoxifen on markers of breast cancer risk in mammogram imaging, breast tissue, and in blood samples.

This description comes directly from the study's public registry record.

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Contact details are listed per location below or on the registry record.

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Locations (4)

City of Hope Comprehensive Cancer CenterDuarte, California, United StatesRecruiting
Northwestern UniversityChicago, Illinois, United StatesRecruiting
University of Kansas Cancer CenterKansas City, Kansas, United StatesRecruiting
Ohio State University Comprehensive Cancer CenterColumbus, Ohio, United StatesRecruiting

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Source record: clinicaltrials.gov/study/NCT05941520