• Patients must provide written informed consent prior to performance of any study-specific procedures and must be willing to comply with treatment and follow-up. Informed consent must be obtained prior to start of the screening process. Procedures conducted as part of the patient's routine clinical management (e.g. imaging tests), obtained prior to signature of informed consent may be used for screening or baseline purposes as long as these procedures are conducted as specified in the protocol.

• Age: 18-80 years

• Histologic diagnosis of soft tissue sarcoma (undifferentiated pleomorphic sarcoma, leiomyosarcoma, alveolar soft part sarcoma) or osteosarcoma confirmed by central pathology review prior to enrolment with an archive tumor sample. A fresh paraffin embedded tumor tissue block must be provided for all subjects for biomarker analysis before and (when feasible) after treatment with investigational products.

• Metastatic/advanced disease in progression in the last 6 months.

• Patients have previously received at least one previous line of systemic therapy

• Measurable disease according to RECIST 1.1 criteria.

• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-1.

• Adequate hepatic, renal, cardiac, and hematologic function.

• Laboratory tests as follows:

‣ Absolute neutrophil count ≥ 1,500/mm³

⁃ Platelet count ≥ 100,000/mm³

⁃ Bilirubin ≤ 1.5 mg/dL

⁃ AST and ALT ≤ 2.5 times upper limit of normal

⁃ Creatinine ≤ 1.5 mg/dL

⁃ Left ventricular ejection fraction ≥ 50% by echocardiogram or MUGA scan.

⁃ Females of childbearing potential must have a negative serum or urine pregnancy test within 72 hours prior to enrollment and agree to use birth control measures during study treatment and for 3 months after its completion. Patients must not be pregnant or nursing at study entry. Women/men of reproductive potential must have agreed to use an effective contraceptive method.