OncoMatch/Clinical Trials/NCT05941520
Acolbifene Versus Low Dose Tamoxifen for the Prevention of Breast Cancer in Premenopausal Women at High Risk for Development of Breast Cancer
Is NCT05941520 recruiting? Yes, currently enrolling (May 2026). This Phase 2 trial studies multiple treatments including Acolbifene Hydrochloride and Tamoxifen for breast atypical hyperplasia.
Treatment: Acolbifene Hydrochloride · Tamoxifen — 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.
Check if I qualifyExtracted eligibility criteria
Cancer type
Breast Carcinoma
Biomarker criteria
Excluded: BRCA1 pathogenic mutation
Excluded: BRCA2 pathogenic mutation
Excluded: PALB2 pathogenic mutation
Allowed: ATM pathogenic mutation
Allowed: BARD1 pathogenic mutation
Allowed: BRIP1 pathogenic mutation
Allowed: CDH1 pathogenic mutation
Allowed: CHEK2 pathogenic mutation
Allowed: MSH6 pathogenic mutation
Allowed: NBN pathogenic mutation
Allowed: NF1 pathogenic mutation
Allowed: PMS2 pathogenic mutation
Allowed: PTEN pathogenic mutation
Allowed: RAD51C pathogenic mutation
Allowed: RAD51D pathogenic mutation
Allowed: TP53 pathogenic mutation
Disease stage
Excluded: Stage INVASIVE BREAST CANCER WITHIN THE PAST 5 YEARS, OTHER PRIOR INVASIVE CANCER > T1 STAGE (OTHER THAN NON-MELANOMA SKIN) WITHIN THE PAST 5 YEARS
Prior invasive breast cancer within the past 5 years; Other prior invasive cancer > T1 stage (other than non-melanoma skin) within the past 5 years
Performance status
ECOG 0–2(Ambulatory, capable of self-care)
Prior therapy
Cannot have received: acolbifene (acolbifene)
Exception: prior treatment for more than 2 months
Prior treatment with acolbifene for more than 2 months
Cannot have received: tamoxifen (tamoxifen)
Exception: prior treatment for more than 2 months
Prior treatment with tamoxifen for more than 2 months
Lab requirements
Kidney function
Creatinine ≤ 2.0 mg/dL
Liver function
Total bilirubin ≤ 1.5 x institutional upper limit of normal; AST ≤ 1.5 x institutional upper limit of normal; ALT ≤ 1.5 x institutional upper limit of normal
Total bilirubin ≤ 1.5 x institutional upper limit of normal (measured within 180 days prior to randomization); AST ≤ 1.5 x institutional upper limit of normal (measured within 180 days prior to randomization); ALT ≤ 1.5 x institutional upper limit of normal (measured within 180 days prior to randomization); Creatinine ≤ 2.0 mg/dL (measured within 180 days prior to randomization)
Structured fields extracted by AI. May contain errors — verify against the official protocol.
US trial sites
- City of Hope Comprehensive Cancer Center · Duarte, California
- Northwestern University · Chicago, Illinois
- University of Kansas Cancer Center · Kansas City, Kansas
- Ohio State University Comprehensive Cancer Center · Columbus, Ohio
Showing up to 5 US sites. See all sites on ClinicalTrials.gov →
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