Tamoxifen Citrate or Z-Endoxifen Hydrochloride in Treating Patients With Locally Advanced or Metastatic, Estrogen Receptor-Positive, HER2-Negative Breast Cancer

Running, not enrolling · Phase 2

Conditions studied: Recurrent Breast Carcinoma, Stage III Breast Cancer AJCC v7, Stage IIIA Breast Cancer AJCC v7, Stage IIIB Breast Cancer AJCC v7, Stage IIIC Breast Cancer AJCC v7, Stage IV Breast Cancer AJCC v6 and v7

In brief

This randomized phase II trial studies how well tamoxifen citrate works compared with z-endoxifen hydrochloride in treating patients with breast cancer that has spread to nearby tissue or lymph nodes or other parts of the body and has estrogen receptors but not human epidermal growth factor receptor 2 (HER2) receptors on the surface of its cells. Estrogen can cause the growth of tumor cells. Hormone therapy using tamoxifen citrate or z-endoxifen hydrochloride may fight breast cancer by lowering the amount of estrogen the body makes. It is not yet known whether tamoxifen citrate or z-endoxifen hydrochloride is more effective in treating patients with breast cancer.

Key facts

Study ID

NCT02311933

Run by

National Cancer Institute (NCI)

People needed

81

Starts

2015-05-28

Expected to finish

2027-02-02

Last updated by the study team

2026-08-06

Who can join

Age: 18 and older. Sex: female. Healthy volunteers: not accepted.

You may qualify if…

• PRE-REGISTRATION ELIGIBILITY CRITERIA
• Women who agree to undergo a standard of care core biopsy of recurrent or metastatic breast cancer to confirm the ER+ (>= 10% nuclear staining) and HER2 negative status
• Patient must have been previously treated with an aromatase inhibitor (either letrozole, anastrozole or exemestane) either in the adjuvant or metastatic setting, and have one of the following types of primary or secondary endocrine resistant disease
• Primary clinical resistance is defined as one of the following:
• Recurrence within the first 2 years of adjuvant endocrine therapy while on aromatase inhibitor therapy
• Progression within first 6 months of initiating first-line endocrine therapy (either aromatase inhibitor or fulvestrant containing regimen) for the treatment of metastatic breast cancer
• Secondary clinical resistance is defined as one of the following:
• Recurrence after year 2 while receiving adjuvant aromatase inhibitor therapy, or within 12 months of completing adjuvant aromatase inhibitor therapy
• Progression occurring 6 or more months after initiating the first endocrine therapy for metastatic disease (either fulvestrant or aromatase inhibitor containing regimen)
• Patients with a history of measurable disease as defined by RECIST criteria or bone only disease are eligible; Note: those patients with non-measurable disease and bone metastases are eligible
• No history of tumors involving spinal cord or heart
• No current evidence of visceral crisis or lymphangitic spread
• No known brain metastases
• Women must be postmenopausal
• Postmenopausal status is verified by:
• Prior bilateral surgical oophorectomy, or
• Age >= 60 years, or
• Age < 60 with no menses for > 1 year with follicle-stimulating hormone (FSH) and estradiol levels within post menopausal range, according to institutional standard
• Prior treatment
• No more than two prior chemotherapy regimens in the metastatic setting
• Prior treatment with an aromatase inhibitor (either anastrozole, letrozole or exemestane), either in the adjuvant or metastatic setting is required
• Unlimited prior endocrine regimens in the metastatic setting, which may have included an everolimus or cyclin dependent kinase (CDK) 4/6 inhibitor (such as palbociclib, abemaciclib or ribociclib) containing regimen
• Prior tamoxifen treatment is allowed in the adjuvant setting, but patients must not have experienced relapse within 1 year of stopping tamoxifen
• No prior treatment with tamoxifen in the metastatic setting
• No prior treatment with endoxifen

Where it is running

• Anchorage Associates in Radiation Medicine — Anchorage, Alaska, United States
• Anchorage Radiation Therapy Center — Anchorage, Alaska, United States
• Alaska Breast Care and Surgery LLC — Anchorage, Alaska, United States
• Alaska Oncology and Hematology LLC — Anchorage, Alaska, United States
• Alaska Regional Hospital — Anchorage, Alaska, United States
• Alaska Women's Cancer Care — Anchorage, Alaska, United States
• Anchorage Oncology Centre — Anchorage, Alaska, United States
• Katmai Oncology Group — Anchorage, Alaska, United States
• Providence Alaska Medical Center — Anchorage, Alaska, United States
• Fairbanks Memorial Hospital — Fairbanks, Alaska, United States
• Mayo Clinic Hospital in Arizona — Phoenix, Arizona, United States
• Mayo Clinic in Arizona — Scottsdale, Arizona, United States
• CHI Saint Vincent Cancer Center Hot Springs — Hot Springs, Arkansas, United States
• NEA Baptist Memorial Hospital and Fowler Family Cancer Center - Jonesboro — Jonesboro, Arkansas, United States
• Kaiser Permanente-Anaheim — Anaheim, California, United States
• PCR Oncology — Arroyo Grande, California, United States
• Sutter Auburn Faith Hospital — Auburn, California, United States
• Sutter Cancer Centers Radiation Oncology Services-Auburn — Auburn, California, United States
• AIS Cancer Center at San Joaquin Community Hospital — Bakersfield, California, United States
• Kaiser Permanente-Baldwin Park — Baldwin Park, California, United States
• Kaiser Permanente-Bellflower — Bellflower, California, United States
• Alta Bates Summit Medical Center-Herrick Campus — Berkeley, California, United States
• Providence Saint Joseph Medical Center/Disney Family Cancer Center — Burbank, California, United States
• Mills-Peninsula Medical Center — Burlingame, California, United States
• Southern Cancer Center PC-Providence — Mobile, Alabama, United States

Full record on ClinicalTrials.gov

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