Pilot Study of [68Ga]Ga-ABY-025 Imaging in Patients Undergoing Treatment With HER2-targeted Therapy

Inclusion Criteria: 1. Age ≥ 18 years. 2. Patients with unresectable locally advanced or metastatic cancer who are eligible for standard of care treatment with HER2-targeted therapy per the discretion of their treating physician for an FDA-approved indication. Patients who are planning to start HER2-targeted therapy at the time of study enrollment. Patients who have recently begun HER2 treatment and have received no more than 6 cycles will be eligible for enrollment. 3. Must have a previous biopsy demonstrating HER2 expression in at least one lesion (HER2+ solid cancer, or breast cancer patients who are HER2+ or HER2-low) as defined by IHC and FISH studies or with HER2 amplification as defined by a liquid biopsy that was done as standard of care testing for the patient's cancer type. 4. Measurable disease on CT, FDG-PET, or MRI imaging for RECIST evaluation; patient must have measurable disease outside the liver. 5. Life expectancy of at least 6 months. Patients with brain metastases are permitted to enroll in this study. Exclusion Criteria: 1. Measurable sites of disease only in the liver. 2. Inability to comply with study procedures. 3. Hypersensitivity or allergy to any component of \[68Ga\]Ga-ABY-025. 4. Pregnant or breastfeeding. 5. HER2-negative cancers that have no FDA approved indication for treatment with HER2-directed therapy. 6. Inability to lie flat for 30 minutes during an imaging session. 7. Medical or psychiatric co-morbidities that, in the opinion of the treating physician, would prevent the patient from successfully participating in the study.