Endoxifen as a hormone treatment for premenopausal ER-positive, HER2-negative breast cancer

Project 2

NIH-funded research Mayo Clinic Rochester · NIH-11176764

This project offers endoxifen, a tamoxifen metabolite pill, as a hormone therapy option for premenopausal women with ER+/HER2- breast cancer who cannot or prefer not to have ovarian suppression.

Quick facts

Grant typeNIH-funded research
Study typeNIH-funded research
Funding institutionMayo Clinic Rochester NIH-funded
Lab location1 site (Rochester, United States)
Project IDNIH-11176764 on NIH RePORTER

What this research studies

If you are a premenopausal woman with ER-positive, HER2-negative breast cancer, this project is testing endoxifen as an alternative to current hormone approaches that include ovarian suppression. The team builds on early phase trials showing endoxifen is safe, absorbed well by mouth, and active against tamoxifen-resistant tumors. The work compares endocrine strategies while monitoring side effects tied to premature menopause such as heart disease and bone loss. Participation would involve regular clinic visits, treatment with endoxifen or standard therapy, and follow-up for cancer outcomes and long-term health effects.

Who could benefit from this research

Good fit: Premenopausal women with ER-positive, HER2-negative breast cancer—particularly those who cannot tolerate or do not want ovarian function suppression—are the ideal candidates.

Not a fit: Postmenopausal patients, those with ER-negative or HER2-positive tumors, or patients already well-controlled on current standard endocrine regimens are unlikely to benefit from this project.

Why it matters

Potential benefit: If successful, endoxifen could provide an effective endocrine therapy that avoids ovarian suppression and its long-term health risks for premenopausal patients.

How similar studies have performed: Previous adjuvant trials showed mixed survival results for aromatase inhibitors plus ovarian suppression and early phase I/II trials of endoxifen have shown it to be safe and active, but larger trials are still needed.

Where this research is happening

Rochester, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Conditions Breast CancerBreast Cancer CellBreast Cancer Patient
Last reviewed 2026-06-13 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.