Trial of 4-Hydroxytamoxifen (4-OHT) Gel in Women Aimed at Reducing Dense Breast Tissue

A study to determine the efficacy of 8 mg/day (4 mg/breast) of BHR-700 gel compared to placebo for reducing breast tissue density in women identified as having dense breast tissue upon analysis of screening mammography. The Primary Study Endpoint being the percent reduction of mammographic breast tissue density on a follow-up mammogram compared to the baseline mammogram after 52 weeks of treatment.

This is a randomized, double blind, placebo-controlled study. Subjects will have been assessed as having mammographically dense breast (heterogeneously dense (C) or extremely dense (D), based on the American College of Radiology (ACR) Breast Imaging-Reporting and Data System (BIRADS©) fifth edition classification) for eligibility.

Approximately 330 subjects will be enrolled at approximately 25 sites in the US and the European Union. Subjects who give informed consent will be stratified, based on whether they are pre/peri or post-menopausal and randomized 2:1 within those groups to receive either 8 mg/day (4 mg/breast) 4-OHT or matching placebo for up to 52 weeks.

Subjects will apply the investigational gel to both breasts once per day until they have completed 52 weeks of study drug administration. There will be, in addition, an optional 52 weeks of open-label treatment for those subjects who choose to continue treatment. Subjects will capture daily gel administration in a diary to monitor compliance.

While on treatment, subjects will return to the clinic for study assessments, a review of adverse events (AEs) and to re-supply study gel at 13, 26, 39, weeks and at 52 weeks for those subjects who have agreed to take part in the open-label phase of the study. During the study, in a case of significant changes in bleeding pattern or other signs/symptoms which could be related to endometrial pathology, the Investigator will perform a uterine ultrasound followed by an endometrial biopsy if indicated.

Open-Label Treatment Phase

Secondary Outcome Measures: • Comparison of breast density measurements (Cumulus and Volpara) • Laboratory parameters will be summarized in a descriptive fashion. • Incidence and severity of AEs will be compared between BHR-700 gel and placebo.

Eligibility Criteria:
Inclusion Criteria:

1. Healthy women age 35 - 75 years with either heterogeneously dense (C) or extremely dense (D), breast tissue on 2D mammography, based on American College of Radiology (ACR) Breast Imaging-Reporting and Data System (BI-RADS©) fifth edition classification) in either breast within 3 months prior to randomization. Mammogram with BI-RADS final assessment category 1 or 2 (negative or benign findings).
2. If the participant is of childbearing potential, she must have a documented negative urine pregnancy test at the time of screening and randomization and no plans to become pregnant for the duration of study participation.
3. Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

1. Participants may not be receiving treatment with any investigational drug or biologic within 30 days of randomization or at any time during the study.
2. Women with a history of allergic reactions attributed to compounds of similar chemical or biologic composition to Tamoxifen.
3. Pregnant women are excluded from this study because the effects of 4-OHT gel on the developing human fetus at the recommended dose and route are unknown.
4. Pregnancy (independent of outcome) and/or lactation within 1 year prior to the screening mammogram.
5. Women with previous history of cancer (including invasive or intra-ductal breast cancer) except for non-melanoma skin cancer.
6. Women who have had a prior mastectomy (unilateral or bilateral), segmental mastectomy, reduction mammoplasty or breast augmentation including implants.
7. Women with surgical breast biopsy(s) performed within 3 years or core biopsy(s) performed within 1 year prior to the screening mammogram.
8. Women with an abnormal mammogram (BI-RADS final assessment category 3-probably benign, 4-suspicious, or 5-malignant findings). Women with BI-RADS 0 assessment (needs additional imaging evaluation) that are subsequently found to have negative (BI-RADS 1) or benign findings (BI-RADS 2), are NOT excluded.
9. Women with only synthetic 2D mammograms generated from 3D (tomosynthesis) are excluded as breast density measurements are not yet validated for synthetic mammograms. Women with combination 2D+3D mammograms are not excluded.
10. Women with active liver disease or thromboembolic disorder.
11. Women with skin conditions such as psoriasis, fungal infections, keloids etc., or tattoos and/or piercings, which in the opinion of the Investigator, would interfere with absorption of the Investigational Product.
12. Women who have had an abnormal gynecology exam within the last three years with clinically significant findings, such as secondary dysmenorrhea, polyps, or atypia, which in the opinion of the Investigator would interfere with the study.
13. Women who have received treatment with Selective Estrogen Receptor Modulators (SERMs) (e.g. tamoxifen, raloxifene) or aromatase inhibitors
14. Women taking estrogen containing contraceptives or Hormone Replacement Therapy (HRT) must discontinue the treatment a minimum of 6 months prior to the screening mammogram. Progestin only contraceptives are permitted.
15. Women with a concurrent illness, disease or condition that, in the opinion of the Investigator, would limit their compliance with study requirements or place them at additional risk.