Actively Recruiting
A Phase 2 Trial of (Z)-Endoxifen and Goserelin as Neoadjuvant Treatment for Premenopausal Women With ER+, HER2- Breast Cancer
Led by Atossa Therapeutics, Inc. · Updated on 2025-10-30
87
Participants Needed
15
Research Sites
21 weeks
Total Duration
On this page
Sponsors
A
Atossa Therapeutics, Inc.
Lead Sponsor
I
InClin
Collaborating Sponsor
AI-Summary
What this Trial Is About
This research evaluates (Z)-endoxifen as a potential treatment for premenopausal women with estrogen receptor positive (ER+) and HER2-negative breast cancer. The study is open-label and includes two parts: a pharmacokinetic (PK) part to understand how the body processes the drug, and a treatment part to assess the drug's effect on tumor growth by measuring the biomarker Ki-67. The trial is sponsored by Atossa Therapeutics, Inc. and aims to determine if (Z)-endoxifen can slow or stop tumor growth in this patient group. Participants in the PK part receive daily (Z)-endoxifen capsules at doses of 20 mg, 40 mg, or 80 mg, with some also receiving a monthly injection of goserelin, which temporarily stops estrogen production by the ovaries. The treatment part uses a combination of (Z)-endoxifen at 40 mg daily plus monthly goserelin injections. After 4 weeks, tumor tissue is sampled via biopsy to measure Ki-67 levels. If Ki-67 is 10% or less, participants may continue treatment for up to 24 weeks; if greater than 10%, they proceed to surgery earlier. Participants attend regular visits for treatment and assessments, including blood tests and breast biopsies to monitor drug levels and tumor response. The main outcomes measured include (Z)-endoxifen blood concentrations and tumor Ki-67 reduction after 4 weeks, along with tumor response after 24 weeks. Study participation lasts up to 6 months, followed by surgery and a one-month follow-up to evaluate safety and treatment effects.
CONDITIONS
Brief Title
(Z)-Endoxifen for the Treatment of Premenopausal Women With ER+/HER2- Breast Cancer
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Female sex assigned at birth; female to male transgender individuals without hormonal therapy may be considered upon approval
- Age 18 years or older
- Not lactating, pregnant, or planning pregnancy in the next year; agrees to prevent pregnancy and not breastfeed during and after treatment
- Willing to use at least one non-hormonal, highly effective contraception method during the study
- Premenopausal status confirmed by menstruation or hormone levels
- Pathologic confirmation of strongly estrogen receptor positive (ER+) breast cancer
- ECOG Performance Status of 0 to 2
- Nottingham Grade 1 or 2 breast cancer
- HER2-negative breast cancer confirmed by guidelines
- Clinical stage T2 or T3 and node status N0 or N1 invasive breast cancer
- MRI within 35 days prior to registration
- Able and willing to give informed consent and provide blood and breast tissue samples for research
You will not qualify if you...
- Bilateral invasive breast cancer or inflammatory breast cancer
- Prior breast cancer diagnosis or treatment, or other active malignancy within past 2 years except specific treated conditions
- Uncontrolled illnesses such as active infections, heart failure, unstable angina, arrhythmias, hypertension, diabetes with HbA1c >7%, or prolonged QTc interval
- Certain co-morbidities including cataracts, retinopathy, history of blood clots, inherited coagulation disorders, or end stage kidney disease needing dialysis
- Lab abnormalities within 28 days prior to registration including high bilirubin or liver enzymes, low platelets, or low hemoglobin
- Recent or current hormonal therapies or androgen-based therapy
- Allergy to study drugs or their components
- Participation in another investigational trial within 6 months
- Known metastatic disease
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 4 weeks initially, with option to continue up to 24 weeks (6 cycles of 28 days)
Participants receive (Z)-endoxifen capsules orally once daily for 4 weeks, with doses of 20 mg, 40 mg, or 80 mg evaluated. Some participants also receive goserelin 3.6 mg by subcutaneous implant approximately every 28 days. Based on tumor response at Week 4, participants may continue treatment for up to 6 cycles (28 days each) or proceed to surgery earlier.
Weekly visits for up to 4 weeks, then visits approximately every 28 days if continuing treatment
Duration - Up to 3 weeks
Participants who complete treatment or discontinue early undergo surgery within 3 weeks after the last treatment cycle or early termination.
1 visit (in-person) for surgery
Trial Site Locations
Total: 15 locations
1
Mayo Clinic Arizona
Phoenix, Arizona, United States, 85054
Actively Recruiting
2
University of Arizona
Tucson, Arizona, United States, 85719
Actively Recruiting
3
California Research Institute
Los Angeles, California, United States, 90027
Actively Recruiting
4
Mayo Clinic Florida
Jacksonville, Florida, United States, 32224
Actively Recruiting
5
Northwestern University
Chicago, Illinois, United States, 60611
Actively Recruiting
6
St. Elizabeth Healthcare
Edgewood, Kentucky, United States, 41017
Actively Recruiting
7
Henry Ford Cancer Institute
Detroit, Michigan, United States, 48202
Actively Recruiting
8
Mayo Clinic Rochester
Rochester, Minnesota, United States, 55905
Actively Recruiting
9
Washington University School of Medicine
St Louis, Missouri, United States, 63110
Actively Recruiting
10
Avera Cancer Institute
Sioux Falls, South Dakota, United States, 57105
Actively Recruiting
11
Vanderbilt Ingram Cancer Center
Nashville, Tennessee, United States, 37204
Actively Recruiting
12
Baylor University
Houston, Texas, United States, 77054
Actively Recruiting
13
Tranquility Research
Webster, Texas, United States, 77598
Withdrawn
14
Bon Secours Cancer Institute
Midlothian, Virginia, United States, 23114
Actively Recruiting
15
Fred Hutchinson Cancer Center
Seattle, Washington, United States, 98109
Actively Recruiting
Research Team
H
Hayley Erickson
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
4
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