(Z)-Endoxifen for the Treatment of Premenopausal Women With ER+/HER2- Breast Cancer

What Was Tested

The trial (phase 2) is built around Goserelin.

This open-label research study is studying (Z)-endoxifen as a possible treatment for pre-menopausal women with ER+/HER2- breast cancer.

(Z)-endoxifen belongs to a group of drugs called selective estrogen receptor modulators or "SERM", which help block estrogen from attaching to cancer cells.

It had four arms (groups): PK Cohort (experimental), Treatment Cohort - Single Treatment Arm (experimental), one (experimental) and one (experimental).

The registry classes the interventions as drug.

Who Took Part

87 planned participants were the target.

It was open to women only aged from 18 years with no upper age limit.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could join: Age 18 years or older. Premenopausal defined as any female who:. Is menstruating or. Is not menstruating (last menstrual period \> 3 months prior to registration) but has a plasma estradiol in the premenopausal range as assessed locally. Eastern Cooperative Oncology Group ECOG Performance Status (ECOG PS) of 0 to 2.

The full record lists 16 inclusion and 27 exclusion criteria; among the exclusions: adequately treated in situ carcinoma of the cervix uteri; adequately treated basal cell carcinoma or localized squamous cell carcinoma of the skin; any other malignancy with a life expectancy of less than 2 years.

How the Study Was Run

The set-up was non-randomized, parallel-group and open-label.

The Goserelin group and the comparison group ran side by side rather than switching.

Everyone knew when Goserelin was being given (open label), which is simpler to run but leaves more room for expectations to affect what is reported.

It started in 2023-02-14 with completion listed for 2026-11.

It ran at 14 sites in United States (14).

Its stated primary purpose is treatment.

What Was Measured

Researchers chose this as the main measure: PK Cohort - (Z)-endoxifen steady-state plasma concentrations (time frame: After 4 weeks of treatment). For analysis Cohort B (Treatment Cohort): determine the objective tumor response rate at 24 weeks (time frame: After 24 weeks of treatment).

It also tracked 26 secondary outcomes, for example PK Cohort - Area under the plasma (Z)-endoxifen concentration-time curve from time zero to last measurable concentration, PK Cohort - Area under the plasma (E)-endoxifen concentration-time curve from time zero to last measurable concentration, PK Cohort - Accumulation and accumulation half-life, PK Cohort - (Z)-endoxifen steady-state clearance, PK Cohort - (E)-endoxifen steady-state clearance and PK Cohort - Maximum plasma (Z)-endoxifen concentration.

What This Means in Plain Language

Put simply, this is a phase 2, non-randomized trial of Goserelin in 87 people.

Its status is active not recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Goserelin compound page, all human trials.