Combined Immunotherapies in Metastatic ER+ Breast Cancer

This study is for women aged 18 to 90 with metastatic (spread to other parts of the body) breast cancer that is hormone receptor-positive (ER+) and HER2-negative (HER2-). You may be eligible if your cancer has progressed after one endocrine therapy, or if you are starting CDK4/6 inhibition with endocrine therapy for the first time. The study is testing if adding Stereotactic Body Radiation Therapy (SBRT) to each metastatic lesion improves outcomes when combined with standard treatments like letrozole (Femara) and palbociclib. Researchers will measure how long you live without your cancer getting worse (progression-free survival) for up to 36 months. The study aims to enroll 102 participants, but its current recruitment status is unclear.

Study design: This is an interventional, randomized study involving 102 planned participants. Patients are assigned to receive either standard therapy or standard therapy plus SBRT.
What's involved: Patients in one group will start letrozole, then add palbociclib on day 21 after completing I-SBRT, which occurs on days 1-12.
Compensation: Not stated in the trial record.
Follow-up: Your progression-free survival will be measured at the end of the study, for up to 36 months.

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Combined Immunotherapies in Metastatic ER+ Breast Cancer

Recruiting

PHASE2Ages 18–90InterventionalTreatment

Weill Medical College of Cornell University

~102 participants

Updated 2025-12-15 on ClinicalTrials.gov

What's tested:Stereotactic Body Radiation Therapy (SBRT) (50GY in 5 fractions)Letrozole 2.5Mg TabPalbociclib 125mg

At a glance

Recruiting sites

3 of 3 listed sites are recruiting right now

RecruitingSuspended, closed, or not yet open

What they're measuring

Progression free survival (PFS) will be measured

Measured over End of study, up to 36 months.

Conditions

Breast Cancer

Where it's being run

3 sites across 1 states

New York3

Study leadership

Silvia Formenti, M.D. · PRINCIPAL_INVESTIGATOR · Weill Medical College of Cornell University

Who to contact

Fabiana Gregucci, M.D.

[email protected]

646-962-3110

Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Female ≥ 18 years of age pre and post-menopausal

Metastatic disease (≤ 5 sites of measurable disease by RECIST)

Eligible for treatment with CDK4/6 + aromatase inhibitors

Premenopausal status is defined as either:

Patient had last menstrual period within the last 12 months, OR

If on tamoxifen or toremifene within the past 14 days, plasma estradiol and FSH must be in the premenopausal range per local normal range, OR

In case of therapy-induced amenorrhea, plasma estradiol and/or FSH must be in the premenopausal range per local normal range.

Patients who have undergone bilateral oophorectomy are eligible.

Post-menopausal status defined as either 1) at least 2 years without menstrual period or 2) patients older than 50 with serological evidence of post-menopausal status or 3) hysterectomized patients of any age with FSH confirmation of post-menopausal status.

Eastern Cooperative Oncology Group (ECOG) performance status 0-1

Biopsy proven diagnosis of HR+HER2- metastatic breast cancer. ER expression is \>10%

Patient needs to be able to understand and demonstrate a willingness to sign a written informed consent document

Hematological WBC ≥ 2000/uL

Absolute neutrophil count (ANC) ≥1500/µL

Platelets ≥100 000/µL

Hemoglobin ≥9.0 g/dL or ≥5.6 mmol/La Renal Creatinine OR Measured or calculated creatinine clearance (GFR can also be used in place of creatinine or CrCl) ≤1.5 × ULN OR

AST (SGOT) and ALT (SGPT) ≤2.5 × ULN

Coagulation International normalized ratio (INR) OR prothrombin time (PT)

Activated partial thromboplastin time (aPTT) ≤1.5 × ULN unless the participant is receiving anticoagulant therapy if PT or aPTT is within the therapeutic range of intended use of anticoagulants

Exclusion

Active connective tissue disorders, such as lupus or scleroderma requiring flare therapy

Current use of systemic chemotherapy, endocrine therapy or HER2-neu targeted therapy

Any lesion \>5 cm in greatest diameter.

Inability to obtain histologic proof of metastatic breast cancer

Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug.

Has a known additional malignancy (second primary) that is progressing or has required active treatment within the past 3 years. Note: Participants with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or carcinoma in situ (e.g. cervical cancer in situ) that have undergone potentially curative therapy are not excluded.

Has active autoimmune disease that has required systemic treatment in the past 2 years (i.e. with use of disease modifying agents, corticosteroids or immunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment.

Has an active infection requiring systemic therapy. Has a known history of Human Immunodeficiency Virus (HIV). Note: No HIV testing is required unless mandated by local health authority.

Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.

Patients with uncontrolled brain metastases

What this trial measures

Progression free survival (PFS) will be measuredEnd of study, up to 36 months.
Progression free survival (PFS) is defined as the time from the start of study treatment until the disease progression or death.

Trialytics