OlaReDo - Olaratumab and Rechallenge With Doxorubicin in Soft Tissue Sarcoma Patients

Inclusion Criteria: 1. Patients must have histologically confirmed soft tissue sarcoma (STS) Note: Evidence of disease progression at study entry is required. 2. Treated in any order (neoadjuvant, adjuvant or for metastatic disease) with an anthracycline containing chemotherapy (The participant may have had any number of prior systemic cytotoxic therapies for advanced/metastatic disease. All previous anticancer treatments must be completed ≥ 3 weeks (21 days) prior to first dose of study drug.) 3. No progression on prior therapy with anthracyclines or within three months after stopping this therapy 4. Signed written informed consent 5. Men and women aged ≥ 18 years 6. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 7. Locally advanced (unresectable) or metastatic disease 8. Presence of measurable or non-measurable but evaluable disease as defined by the Response Evaluation Criteria in Solid Tumors (RECIST 1.1, Eisenhauer et al. 2009) 9. Adequate haematologic, organ, and coagulation function within 2 weeks (14 days) prior to enrollment: * Absolute neutrophil count (ANC) ≥ 1,500/mm3; G-CSF is not permitted within 2 weeks (14 days) prior to enrollment * Platelet count ≥ 100,000/mm3 * Creatinine clearance ≥ 45 mL/min (calculated by using the Cockcroft-Gault formula (refer to study protocol Appendix 4) * Total bilirubin ≤ upper limit of normal (ULN). In patients with Gilbert's Syndrome, total bilirubin should be \< 3 mg/dL * AST/ALT ≤ 3.0 x upper limit of normal (ULN); in case of liver involvement, AST/ALT ≤ 5.0 x are acceptable * Haemoglobin ≥ 9 g/dl. If haemoglobin \<9 g/dl, blood transfusion is permitted. If haemoglobin cannot be enhanced to ≥ 9 g/dl, patient cannot be included into the study * International Normalized Ration (INR) ≤ 1.5 or prothrombin time (PT) ≤ 1.5 x ULN * Partial thromboplastin time (PTT or aPTT) ≤ 1.5 x ULN if not on anticoagulant therapy. For patients receiving anticoagulants, coagulation parameters within the intended or expected range for their therapeutic use are allowed. Patients must have no history of active bleeding (defined as within 14 days of first dose of study drug) or pathological condition that carries a high risk of bleeding (for example, tumor involving major vessels or known esophageal varices) * If routine urinalysis ≥2+ proteinuria, patient must have ≤1000 mg protein on a 24-hour urine, or urine protein/creatinine ratio ≤1 on spot urine 10. Left ventricular ejection fraction (LVEF) ≥50% assessed within 28 days prior to enrollment 11. Females of child-bearing potential must have a negative serum pregnancy test within 7 days prior to enrollment (refer to study protocol Appendix 3) 12. Females of child-bearing potential and males and must agree to use highly effective contraceptive precautions during the trial and up to 6 months following the last dose of study drug (refer to study protocol Appendix 3) 13. The participant has, in the opinion of the investigator, a life expectancy of at least 3 months Exclusion Criteria: 1. Diagnosis of GIST or Kaposi sarcoma 2. Active central nervous system (CNS) or leptomeningeal metastasis (brain metastasis) at the time of enrollment. Participants with a history of a CNS metastasis previously treated with curative intent (for example, stereotactic radiation or surgery) that have not progressed on follow-up imaging, have been asymptomatic for at least 60 days and are not receiving systemic corticosteroids and/or anticonvulsants, are eligible. Participants with signs or symptoms of neurological compromise should have appropriate radiographic imaging performed before enrollment to rule out brain metastasis 3. Prior radiotherapy of the mediastinal/pericardial area or whole pelvis radiation 4. The participant has symptomatic congestive heart failure (CHF), or severe cardiac arrhythmia 5. The participant has unstable angina pectoris, angioplasty, cardiac stenting, or myocardial infarction within 6 months of enrollment 6. The participant has a QTcB interval calculated using Bazett's formula interval of \>450 milliseconds (msec) for males and \>470 msec for females on screening electrocardiogram (ECG) 7. Females who are pregnant or breastfeeding 8. Known allergy to any of the treatment components including a history of allergic reactions attributed to compounds of chemical or biological composition similar to olaratumab, dexrazoxane or doxorubicin 9. The participant has a known active fungal, bacterial, or viral infection including human immunodeficiency virus (HIV) or viral (A, B, or C) hepatitis (screening is not required) 10. Known history of active bleeding (defined as within 14 days of first dose of study drug) or pathological condition that carries a high risk of bleeding (for example, tumor involving major vessels or known esophageal varices) 11. History of another primary cancer, with the exception of i) curatively treated non-melanomatous skin cancer or ii) curatively treated cervical carcinoma in situ or iii) other primary non-haematologic malignancies or solid tumor treated with curative intent, no known active disease and no treatment administered during the last 3 years prior to enrollment 12. Electively planned or required major surgery during the course of the clinical trial 13. Any condition that, in the opinion of the investigator, would compromise the well-being of the participant or the study or prevent the participant from meeting or performing study requirements 14. On-treatment participation in another clinical study in the period 30 days prior to start of study treatment and during the study 15. Legal incapacity or limited legal capacity 16. Any condition that requires concomitant vaccination with yellow fever vaccine