Clinical Trial Finder

Inclusion Criteria:

• - Documented informed consent of the participant and/or legally authorized representative.

• - Women with documented metastatic HER2 positive breast cancer (American Society of Clinical Oncology [ASCO] College of American Pathologist [CAP] guidelines) who have brain metastases.

• - Age > 18 years.

• - Eastern Cooperative Oncology Group (ECOG) 0-2.

• - Patients with leptomeningeal disease will be considered eligible.

• - Planned therapy with fam-trastuzumab deruxtecan.

• - Left ventricular ejection fraction (LVEF) > 50% - Absolute neutrophil count (ANC) > 1.5 x 10^9/L.

• - Platelets > 100 x 10^9/L.

• - Hemoglobin > 9 g/dL.

• - Total (T.

) bilirubin < 3 x upper limit of normal (ULN)

• - Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) < 5 x ULN.

• - Creatinine clearance > 30 ml/min (by Cockcroft-Gault formula) - Activated partial thromboplastin time (aPTT) < 1.5 x ULN.

• - Prior therapy for central nervous system (CNS) disease is allowed, but at least 1 lesion > 1.5 cm is evident on MRI.

Exclusion Criteria:

• - Need for immediate local intervention for brain metastases.

• - Noninfectious interstitial lung disease or pneumonitis requiring glucocorticoids.

• - Clinically significant corneal disease.

- Myocardial infarction < 6 months before, congestive heart failure (CHF), unstable angina, or serious cardiac arrhythmia

PRIMARY OBJECTIVES:

• I. Evaluate the feasibility of 64Cu-DOTA-trastuzumab PET imaging in patients with HER2+ breast cancer metastatic to the brain.

• II. Evaluate if HER2+ breast cancer patients with brain metastasis who are responders to fam-trastuzumab deruxtecan have higher maximum standardized uptake value (SUVmax) (minimum over all lesions in the brain) than non-responders.

SECONDARY OBJECTIVE:

• I. Evaluate if the minimum SUVmax of all quantifiable lesions in a given patient is associated with time to progression in the brain.

OUTLINE: Patients receive trastuzumab intravenously (IV) over 15 minutes on day 0. Patients then receive 64Cu-DOTA-trastuzumab IV and then undergo PET/MRI scan on day 1. Patients undergo repeat brain MRI every 6 weeks for 24 weeks and then every 9 weeks until disease progression. Patients then receive trastuzumab deruxtecan IV every 21 days in the absence of disease progression or unacceptable toxicity.

Arms

Experimental: Treatment ( 64Cu-DOTA-trastuzumab PET/MRI)

Patients receive trastuzumab IV over 15 minutes on day 0. Patients then receive 64Cu-DOTA-trastuzumab IV and then undergo PET/MRI scan on day 1. Patients undergo repeat brain MRI every 6 weeks for 24 weeks and then every 9 weeks until disease progression. Patients then receive trastuzumab deruxtecan IV every 21 days in the absence of disease progression or unacceptable toxicity.

Interventions

Other: - Copper Cu 64-DOTA-Trastuzumab

Given IV

Procedure: - Magnetic Resonance Imaging

Undergo PET/MRI

Device: - Positron Emission Tomography

Undergo PET/MRI

Biological: - Trastuzumab

Given IV

Biological: - Trastuzumab Deruxtecan

Given IV