(Z)-Endoxifen for the Treatment of Premenopausal Women With ER+/HER2- Breast Cancer (NCT05607004) | Clinical Trial Compass
Active — Not RecruitingPhase 2
(Z)-Endoxifen for the Treatment of Premenopausal Women With ER+/HER2- Breast Cancer
United States87 participantsStarted 2023-02-14
Plain-language summary
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. This study has two parts: a pharmacokinetic part and a treatment part.
The PK part (how the body processes the drug) will enroll about 18 participants. All participants will take (Z)-endoxifen capsules daily. Twelve participants will be randomly assigned (50/50 chance) to take (Z)-endoxifen alone or (Z)-endoxifen with a monthly injection of goserelin a drug that temporarily stops the ovaries from making estrogen. This part will help determine the best dose of (Z)-endoxifen by measuring the drug levels in the blood and how long the body takes to remove it.
The Treatment Cohort has been simplified to a single study arm (Z)-endoxifen + goserelin. Up to 20 participants will be enrolled that have a baseline Ki-67 ≤ 10% and 45 participants will be enrolled that have a baseline Ki-67\>10%.
A key goal of the study is to see if (Z)-endoxifen can slow down or stop tumor growth as measured by a reduction in Ki-67 levels. Tumor tissue samples will be taken by breast biopsy after about 4 weeks of treatment to check levels of this biomarker. If the tumor shows signs of response, participants can continue treatment for up to 24 weeks or until they have surgery.
Study participation is up to 6 months (24 weeks of treatment) followed by surgery and a one-month follow up visit.
Who can participate
Age range
18 Years
Sex
FEMALE
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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Female sex assigned at birth. Female to male transgender individuals who have not had any hormonal therapy may be considered for the trial after review and approval from the medical monitor and study sponsor.
. Age 18 years or older
. Not lactating, pregnant, or planning to become pregnant in the next year and agrees to take adequate steps to prevent becoming pregnant beginning at informed consent, during treatment and for 9 months after last dose and agree to not breast feed during treatment and for 3 months after last dose.
. Must agree to use at least one non-hormonal highly effective method of contraception for the entire duration of study participation beginning at informed consent. Highly effective methods of birth control are defined as those, alone or in combination, that resulted in a low failure rate of \<1% per year when used consistently and correctly such as intrauterine devices (IUDs, non-hormonal such as copper IUD), bilateral tubal occlusion, sexual abstinence or vasectomized partner
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
. is not menstruating (last menstrual period \> 3 months prior to registration) but has a plasma estradiol in the premenopausal range as assessed locally
. Pathologic confirmation of strongly estrogen receptor positive (ER+) (defined as estrogen receptor \[ER\] ≥ 67% or Allred Score 6-8) by local institution protocol
Exclusion criteria
. Bilateral invasive breast cancer; Inflammatory breast cancer defined as clinically significant erythema of the breast and/or documented dermal lymphatic invasion or bilateral invasive breast cancer (patients with pre-malignant disease or DCIS/LCIS in contralateral breast are eligible)
. Prior diagnosis or treatment for breast cancer, including carcinoma in situ, or history of any other active malignancy within the past 2 years prior to study entry with the exception of:
. 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
. Any uncontrolled intercurrent illness including, but not limited to:
. Ongoing or active infection requiring systemic treatment with strong inhibitors/inducers of CYP450 enzymes (including bacterial infection, fungal infection, or detectable viral infection).