Effect of Oral (Z)-Endoxifen in Premenopausal Women With Measurable Breast Density

A Phase 2, Randomized, Double-blinded, Placebo-controlled, Dose-Response Study of Oral (Z)-Endoxifen in Premenopausal Women With Measurable Breast Density

Status

Active, not recruiting

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05068388

Enrollment

240

Registered

2021-10-05

Start date

2021-12-21

Completion date

2025-12-31

Last updated

2024-04-26

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast Density

Brief summary

This is a randomized, double-blinded, placebo-controlled dose-response efficacy study of oral (Z)-endoxifen in premenopausal women with measurable breast density. There will be 5 in-clinic visits (Screening, Day 1, Months 1, 3 and 6) and 3 self-report visits (Months 2, 4 and 5). Standard of care mammograms will be used for the screening mammogram as well as the 24-month follow up visit.

Interventions

DRUGZ-Endoxifen

Z-Endoxifen

DRUGPlacebo

Placebo

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

FEMALE

Age

40 Years to 55 Years

Healthy volunteers

Yes

Inclusion criteria

1. Premenopausal women (defined as having at least one menstruation during the prior 12 months; women with an intrauterine device are considered premenopausal if \<52 years) 2. Women of childbearing potential using a highly effective method of birth control\* throughout the study period and willing to comply with monthly pregnancy testing 3. Screening mammogram performed within 3 month of study inclusion 4. Mammographic density assessed as BI-RADS® score B, C, or D 5. Must have given written informed consent before any study-related activities are carried out and must be able to understand the full nature and purpose of the trial, including possible risks and adverse effects

Exclusion criteria

1. Mammographic BI-RADS® malignancy code ≥3 at baseline mammography 2. Any previous diagnosis of breast cancer, including carcinoma in situ, or any other cancer (non-melanoma skin cancer and in situ cancer of the cervix are not

Design outcomes

Primary

Measure	Time frame	Description
Change of mammographic density area (cm2) assessed by iCAD® software	6 months	Change from baseline

Secondary

Measure	Time frame	Description
Comparison of adverse events	6 months	assessment of adverse events
Change of mammographic density area (cm2) assessed by iCAD® software	3 months	Change from baseline
Change of mammographic density area (cm2) assessed by Stratus software	6 months	Change from baseline
Change from baseline responses to the Breast Cancer Prevention Trial Eight Symptom Scale (BESS)	6 months	5-point Likert-type scale

Countries

Sweden

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026