Impact of HSD3B1 gene mutation on breast cancer treatment

Association of HSD3B1 Genotype With Response to Preoperative Letrozole Therapy Among Postmenopausal Women With Estrogen-Receptor Positive (ER+) HER2/Neu-Negative (HER2-) Invasive Carcinomas of the Breast

PHASE4 · University of Washington · NCT05183828

This study is testing if a specific gene mutation affects how well the breast cancer treatment letrozole works for people with stage I-III breast cancer.

Quick facts

PhasePHASE4
Study typeInterventional
Enrollment68 (estimated)
Ages18 Years and up
SexFemale
SponsorUniversity of Washington (other)
Drugs / interventionschemotherapy, radiation
Locations1 site (Seattle, Washington)
Trial IDNCT05183828 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates how the HSD3B1 (1245C) gene mutation influences the effectiveness of aromatase inhibitor therapy, specifically letrozole, in treating stage I-III breast cancer. Participants will receive letrozole orally for a specified duration while undergoing tumor resection if necessary. Additionally, saliva samples will be collected to analyze the genetic mutation's impact on treatment outcomes. The study aims to determine if the mutation reduces the efficacy of the therapy, potentially guiding future treatment strategies.

Who should consider this trial

Good fit: Ideal candidates include postmenopausal females aged 18 and older with histologically confirmed stage I-III ER+ HER2-negative breast cancer.

Not a fit: Patients with non-ER+ breast cancer or those who are not postmenopausal may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to more personalized treatment approaches for breast cancer patients based on their genetic profiles.

How similar studies have performed: Other studies have shown promising results in understanding genetic mutations' effects on cancer treatment, suggesting this approach may yield valuable insights.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Subject must be female age \>= 18 years.
* Postmenopausal as defined by at least one of the following:

  * Age \>= 60 years;
  * Age \< 60 years and cessation of regular menses for at least 12 consecutive months with no alternative pathological or physiological cause; or serum estradiol and follicle stimulating hormone levels within the local laboratory's normal reference range for postmenopausal females;
  * Documented bilateral oophorectomy.
* Histologically confirmed diagnosis of carcinoma of the breast, clinical stage I-III.
* Minimum tumor diameter of 1.0 cm as assessed by palpation or imaging (e.g., ultrasound) and with enough tumor left after the initial diagnostic biopsy to provide tumor tissue during the planned tumor resection.
* Candidate for surgical resection.
* ER+ breast cancer (\> 1% positive stained cells) based on the most recent tumor biopsy documented by a local laboratory or medical record.
* Ki67 \>= 10%.
* 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.
* Stated willingness to comply with all study procedures and availability for the duration of the study.
* Prior use of hormone contraceptives and replacement therapy is allowed (e.g., estrogen and/or progestin) if discontinued \> 6 months prior to diagnosis. Vaginal preparations are allowed.
* Ability to take oral medication and be willing to adhere to the study intervention.

Exclusion Criteria:

* Pre-treatment tumor biopsy sample not likely to provide adequate tissue sections for biomarker assays.
* Inoperable or metastatic disease.
* Subjects who have received any prior therapy for breast cancer, including radiotherapy, surgery, and cytotoxic and endocrine treatments.
* The subject must not have had hormonal therapy for breast cancer treatment or for breast cancer prevention within 1 year prior to study enrollment. (Note: Synchronous breast, cancer (including bilateral breast cancer) at separate sites is permissible, provided the patient does not receive medical treatments for breast cancer or radiation therapy to the ipsilateral breast during the study intervention period.
* Subjects with plans to undergo neoadjuvant chemotherapy.
* Use of hormonal contraceptives within 6 months of diagnosis.
* Treatment with another investigational drug or other intervention within 28 days before the first administration of letrozole.
* History of allergic reactions/hypersensitivity attributed to compounds of similar chemical or biologic composition to letrozole or any ingredients.
* Uncontrolled current illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.

Where this trial is running

Seattle, Washington

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Anatomic Stage I Breast Cancer AJCC v8, Anatomic Stage II Breast Cancer AJCC v8, Anatomic Stage III Breast Cancer AJCC v8, Breast Adenocarcinoma, Invasive Breast Carcinoma of No Special Type

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.