GD2-SADA:177Lu-DOTA Complex in Patients With Solid Tumors Known to Express GD2

Inclusion Criteria: * Signed informed consent from patient, legal guardian(s) and/or adolescents obtained in accordance with local regulations. Pediatric patients must provide assent as required by local regulations. * Age ≥18 years at the time of informed consent, for High Risk Neuroblastoma \& sarcoma age ≥16 years of age at time of informed consent/assent * Measurable disease according to RECIST 1.1 * ECOG performance status 0-1 * Expected survival \>3 months * Platelet counts ≥100,000 cells/mm3 * Hemoglobin ≥9 g/dL * Adequate renal function with serum creatinine ≤1.5 mg/dL or creatinine clearance ≥60mL/min as calculated using the Cockcroft-Gault equation * Patient willing and able to comply with the trial protocol Exclusion Criteria: * Systemic chemotherapy, radiotherapy, immunotherapy, or major surgery administered within 3 weeks prior to the first planned dosing of the IMP per protocol * Patients receiving any other investigational therapy for their cancer within 3 weeks prior to the first planned dosing of the IMP per protocol * Ongoing radiation toxicities from prior RT therapy * Patients with a diagnosis of autoimmune diseases or immunodeficiencies or documented infection with human immunodeficiency virus (HIV) or hepatitis B or C virus (active) * Prior treatment with anti-GD2 antibody