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ETHAN Study: Treatments for Male Breast Cancer

This study is for men with stage I-III hormone receptor-positive (HR+) and HER2-negative breast cancer that has not yet been surgically removed. Researchers want to find out how well different hormone therapies work before surgery. You would receive one of four treatment combinations: Tamoxifen, Anastrozole, Degarelix (an injection to suppress hormones), or Abemaciclib. Tamoxifen is the usual treatment for men, but this study also looks at Anastrozole (often used in women), and adding Degarelix or Abemaciclib (which have helped women with breast cancer). Success will be measured by changes in cancer cell growth (Ki-67) and how much cancer remains at the time of surgery (RCB index). The study status is unclear, but it plans to enroll about 60 men.

Study design
This is an open-label, multicenter, randomized study with about 60 male participants. It has two phases: a 3-week initial treatment period, followed by 4 months of one of four treatment combinations.
What's involved
You would undergo screening for eligibility, receive study treatments, have laboratory tests, and complete quality of life questionnaires. The study involves a 3-week initial treatment phase and a 4-month treatment phase.
Compensation
Not stated in the trial record.
Follow-up
After completing treatment, participants will be followed for up to 10 years.

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NCT05501704

ETHAN - ET for Male BC

Recruiting
PHASE2Ages 18+InterventionalTreatment
Jose Pablo Leone
~60 participants
Updated 2026-08-24 on ClinicalTrials.gov
What's tested:TamoxifenAnastrozoleDegarelixAbemaciclib

At a glance

Recruiting sites
9 of 9 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Change in Ki-67
Measured over At the end of the 3-week window period.
+1 more outcome measured

Conditions

Male Breast Cancer
Hormone Receptor-positive Breast Cancer
Hormone Receptor Negative Breast Carcinoma

Explore related trials

Breast Carcinoma

Where it's being run

9 sites across 8 states
Pennsylvania2
District of Columbia1
Florida1
Massachusetts1
Minnesota1
North Carolina1
Tennessee1
Texas1

Study leadership

  • Jose Pablo Leone, MD · PRINCIPAL_INVESTIGATOR · Dana-Farber Cancer Institute

Who to contact

Jose Pablo Leone, MD
[email protected]
617-789-2903
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Men aged 18 years or older, with diagnosis of invasive breast cancer who have not undergone surgical resection of the primary tumor and axillary nodes.
Stage I, II, or III per American Joint Committee on Cancer (AJCC) staging 8th edition (112).
Breast cancer must be hormone receptor-positive and HER2-negative according to definition below assessed by local pathology.
Hormone receptor-positive is defined as: positivity for at least one of the hormone receptors (estrogen receptor \[ER\] or progesterone receptor \[PR\]) by IHC. ER and PR assays are considered positive if there are \> 1% positive tumor nuclei in the samples.
HER2-negative is defined per the current American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline (113).
Patients with multifocal or multicentric disease are eligible if the treating investigator has determined the patient should be treated as ER-positive and HER2-negative.
Bilateral breast cancers are allowed if the treating investigator has determined the patient should be treated as ER-positive and HER2-negative.
Patients with a history of ipsilateral or contralateral DCIS or LCIS are eligible.
ECOG performance status ≤ 2.
Required laboratory values demonstrating adequate organ function:
ANC ≥ 1000/mm3
Hemoglobin ≥ 8 g/dl
Platelets ≥ 50,000/mm3
Serum creatinine ≤ 3.0 x ULN (institutional)
Total bilirubin ≤ 2.0 x ULN (institutional).
AST and ALT ≤ 5.0 x ULN (institutional)
Men with partners of childbearing potential must be willing to use one highly effective form of non-hormonal contraception or two effective forms of non-hormonal contraception by the patient and/or partner and continue its use for the duration of the study treatment and for 6 months after the last dose of study treatment.
Non-English-speaking patients are eligible but will be exempt from patient-completed questionnaires.
Willing and able to sign informed consent.
Willing to undergo breast biopsy after completion of window phase.
Patient is able to swallow oral medications.

Exclusion

Prior endocrine therapy, chemotherapy, radiation therapy, or investigational therapy for the current breast cancer diagnosis.
Prior endocrine therapy, systemic therapy, radiation therapy, or investigational therapy for any other malignancy within the past 12 months.
Diagnosis of inflammatory breast cancer (T4d).
Other concurrent serious diseases that may interfere with planned treatment, including severe cardiac disease, congestive heart failure (CHF) of New York Heart Association (NYHA) Class III or higher, severe pulmonary conditions/illness, uncontrolled infections.
The patient has serious and/or uncontrolled preexisting medical condition(s) that, in the judgment of the investigator, would preclude participation in this study (for example, interstitial lung disease, severe dyspnea at rest or requiring oxygen therapy, severe renal impairment \[e.g. estimated creatinine clearance \<30ml/min\], history of major surgical resection involving the stomach or small bowel, or preexisting Crohn's disease or ulcerative colitis or a preexisting chronic condition resulting in baseline Grade 2 or higher diarrhea).
The patient has active systemic bacterial infection (requiring intravenous \[IV\] antibiotics at time of initiating study treatment), fungal infection, or detectable viral infection (such as known human immunodeficiency virus positivity or with known active hepatitis B or C \[for example, hepatitis B surface antigen positive\]. Screening is not required for enrollment.
The patient has a personal history of any of the following conditions: syncope of cardiovascular etiology, ventricular arrhythmia of pathological origin (including, but not limited to, ventricular tachycardia and ventricular fibrillation), or sudden cardiac arrest.

What this trial measures

  • Change in Ki-67At the end of the 3-week window period.

    Ki-67 will be evaluated by ImmunoHistoChemistry (IHC) following consensus recommendations using imaging analysis methods.

  • RCB indexAt time of surgery.

    RCB will be determined using data from each participating institution pathology department, and will be reviewed by the study team pathologist.