Inclusion Criteria:

          1. Age ≥ 16 years old

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

          3. Locally advanced disease and/or metastatic disease

          4. Measurable or evaluable disease with RECIST v1.1

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

          6. 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

          7. Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 2

          8. Adequate bone marrow function

          9. Adequate organ function

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

         11. Cardiac ejection fraction ≥50% as measured by echocardiogram

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

         13. 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.

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

        Exclusion Criteria:

          1. Other primary malignancy with <5 years clinically assessed disease free interval,
             except basal cell skin cancer, cervical carcinoma in situ or other neoplasm judged to
             entail a low risk of relapse

          2. Previous treatment with radiation therapy within 14 days of first day of study drug
             dosing, or patients who have not recovered from adverse events due to agents
             previously administered

          3. Previous radiotherapy to 25% of the bone marrow

          4. Major surgery within 2 weeks prior to study entry

          5. Participation in another clinical study with an investigational product, which last
             dose was taken less than 4 weeks prior to the start of the treatment.

          6. Persistent toxicities (≥ grade 2) with the exception of alopecia, caused by previous
             anticancer therapies.

          7. Pregnancy or breast feeding

          8. Grade III/IV cardiac problems as defined by the New York Heart Association Criteria

          9. Medical history of arterial thrombotic or embolic events such as cerebrovascular
             accident (including transient ischemic attacks), or pulmonary embolism within 6 months
             prior to the initiation of study treatment

         10. Known brain metastasis

         11. Known chronic liver disease (i.e. chronic active hepatitis and cirrhosis)

         12. Known diagnosis oh human deficiency virus (HIV) infection

         13. Active or chronic hepatitis B or C requiring treatment with antiviral therapy

         14. Medical history of hemorrhage or a bleeding event ≥ Grade 3 within 4 weeks prior to
             the initiation of study treatment

         15. Evidence of any other serious or unstable illness, or medical, psychological, or
             social condition, that could jeopardize the safety of the subject and/or his/her
             compliance with study procedures, or may interfere with the subject's participation in
             the study or evaluation of the study results

         16. Known hypersensitivity to any of the study drugs, study drug classes, or excipients in
             the formulation of the study drugs

         17. Expected non-compliance to medical regimens