• Age ≥ 16 years old

• Histological centrally confirmed diagnosis of skeletal or extra-skeletal MCS with the documented presence of HEY1-NCOA2 fusion

• Locally advanced disease and/or metastatic disease

• Measurable or evaluable disease with RECIST v1.1

• Evidence of progression by RECIST v1.1 during the 6 months before study entry

• Patients must be pre-treated with at least one prior chemotherapy treatment containing anthracyclines for the advanced phase of disease and with a maximum of 3 lines

• Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 2

• Adequate bone marrow function

• Adequate organ function

⁃ Female patients of childbearing potential must have negative pregnancy test within 7 days before initiation each cycle of chemotherapy.

⁃ Cardiac ejection fraction ≥50% as measured by echocardiogram

⁃ No history of arterial and/or venous thromboembolic event within the previous 12 months

⁃ The patient or legal representative must be able to read and understand the informed consent form and must have been willing to give written informed consent and any locally required authorisation before any study-specific procedures, including screening evaluations, sampling, and analyses.

⁃ Any other factors, that, at judgment of investigator, could affect the safety of the patients according to the available trabectedin safety data