64-Cu Labeled Brain PET/MRI for MM-302 in Advanced HER2+ Cancers With Brain Mets

Inclusion Criteria: * Histologically confirmed advanced solid tumor malignancy with documented HER2 overexpression or gene amplification on prior archival tumor tissue by CLIA-certified laboratory * New or progressive brain metastases with at least one metastasis measuring ≥ 1 cm in longest diameter on MR imaging * Patients may have extra-cranial metastatic disease but this is not required for study entry * Neurologically stable as defined by ALL of the following: * Stable or decreasing dose of steroids and anti-convulsants for at least 14 days prior to study entry * No clinically significant mass effect, midline shift, or impending herniation on baseline brain imaging * No significant focal neurologic signs and/or symptoms which would necessitate radiation therapy or surgical decompression in the judgment of the treating clinician * Prior radiation therapy for treatment of brain metastases completed at least 4 weeks prior to study entry * Prior radiation therapy for brain metastases allowed but must have been at least 4 weeks prior to study entry and follow up imaging is not consistent with pseudoprogression in the judgment of treating clinician * Patients must be ambulatory with ECOG performance status of 0 - 1. * Adequate organ function, including absolute neutrophil count (ANC) ≥1500 cells/uL, hemoglobin ≥9.0 gm/dL, platelets ≥100,000 cells/uL, estimated creatinine clearance ≥50 mL/min (by the Cockcroft Gault equation), bilirubin \<1.5x ULN (unless Gilbert's is suspected), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) \<1.5x ULN (\< 3x ULN if known liver metastases). * Ejection fraction as assessed by MUGA or echocardiogram \> 50% * Prior cumulative doxorubicin exposure \< 300 mg/m2 (or epirubicin equivalent) * Last dose of prior systemic anti-cancer therapy administered at least 5 half-lives or 4 weeks prior to study entry, whichever is shorter * No contra-indications to MRI (e.g. pacemaker, aneurysm clips, severe claustrophobia) * Patients will sign a study-specific IRB-approved consent prior to study entry. Patients must be able and willing to consent and undergo study procedures. * Age ≥18 years old Exclusion Criteria: * Prior treatment with MM-302 * Patients with any class of New York Heart Association (NYHA) CHF or heart failure with preserved ejection fraction (HFPEF) * Patients with a history of known coronary artery disease or a myocardial infarction within the last 12 months * Patients with persistently uncontrolled hypertension (systolic BP \> 160 mm Hg or diastolic BP \> 100 mm Hg) despite optimal medical therapy * Patients with known unstable angina pectoris * Patients with a known history of serious cardiac arrhythmias requiring treatment (exception: controlled atrial fibrillation, paroxysmal supraventricular tachycardia) * Patients with a prolonged QTc interval (≥ 450 ms) * Patients who previously discontinued trastuzumab due to unacceptable cardiac toxicity * Patients with a history of LVEF decline to below 50% during or after prior trastuzumab/lapatinib or other HER2 directed therapy. * Current dyspnea at rest due to complications of advanced malignancy or other disease that requires continuous oxygen therapy. * Any serious and/or unstable pre-existing medical, psychiatric, or other medical condition that could interfere with subject's safety, provision of informed consent, or compliance with study procedures * Presence of leptomeningeal disease in the absence of parenchymal brain metastases