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 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