OncoMatch/Clinical Trials/NCT05183828
Effect of HSD3B1 (1245C) Gene Mutation on Treatment of Stage I-III Breast Cancer
Is NCT05183828 recruiting? Yes, currently enrolling (May 2026). This Phase 4 trial studies Letrozole for anatomic stage i breast cancer ajcc v8.
Treatment: Letrozole — This stage IV trial examines how a mutation in HSD3B1 (1245C) gene affects treatment of stage I-III breast cancer. This trial may help researchers determine if mutations in HSD3B1 decreases the efficacy of aromatase inhibitor therapy such as letrozole. Letrozole may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth.
Check if I qualifyExtracted eligibility criteria
Cancer type
Breast Carcinoma
Biomarker criteria
Required: ESR1 overexpression (> 1% positive stained cells)
ER+ breast cancer (> 1% positive stained cells) based on the most recent tumor biopsy
Required: HER2 (ERBB2) negative (HER2-negative per ASCO/CAP 2018)
HER2-negative breast cancer based on the most recent tumor biopsy and documented by a local laboratory or medical record. HER2-negative tumor is defined per American Society of Clinical Oncology and the College of American Pathologists guidelines, 2018.
Required: MKI67 overexpression (Ki67 >= 10%)
Ki67 >= 10%
Disease stage
Required: Stage I, II, III
Prior therapy
Cannot have received: radiation therapy
Subjects who have received any prior therapy for breast cancer, including radiotherapy, surgery, and cytotoxic and endocrine treatments.
Cannot have received: surgery
Subjects who have received any prior therapy for breast cancer, including radiotherapy, surgery, and cytotoxic and endocrine treatments.
Cannot have received: cytotoxic chemotherapy
Subjects who have received any prior therapy for breast cancer, including radiotherapy, surgery, and cytotoxic and endocrine treatments.
Cannot have received: endocrine therapy
Subjects who have received any prior therapy for breast cancer, including radiotherapy, surgery, and cytotoxic and endocrine treatments.
Cannot have received: hormonal therapy
Exception: not within 1 year prior to study enrollment
The subject must not have had hormonal therapy for breast cancer treatment or for breast cancer prevention within 1 year prior to study enrollment.
Cannot have received: neoadjuvant chemotherapy
Subjects with plans to undergo neoadjuvant chemotherapy.
Structured fields extracted by AI. May contain errors — verify against the official protocol.
US trial sites
- Fred Hutch/University of Washington Cancer Consortium · Seattle, Washington
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