• Histology: undifferentiated pleomorphic sarcoma (stratum 1), bone osteosarcoma (stratum 2), bone or extraskeletal or Ewing sarcoma (stratum 3),

• Advanced non resectable / metastatic disease,

• Recurrent disease or progression after standard therapy,

• Documented progression according to RECIST criteria.

• Have provided tissue of a tumor lesion from \< 3 months old archival tissue sample obtained on locally advanced disease, or metastatis with no subsequent treatment since or from a newly obtained core or excisional biopsy,

• No more of three previous lines of systemic therapy for advanced disease,

• Age ≥ 18 years,

• Eastern Cooperative Oncology Group ≤ 1,

• Measurable disease according to RECIST v1.1 outside any previously irradiated field. At least one site of disease must be uni-dimensionally ≥ 10 mm,

⁃ Life expectancy \> 3 months,

⁃ Participant must have advanced disease and must not be a candidate for other approved therapeutic regimen known to provide significant clinical benefit based on investigator judgement,

⁃ No symptomatic central nervous system disease,

⁃ No chronic use of glucocorticoids.

⁃ Adequate hematological, renal, metabolic and hepatic function,

⁃ No prior or concurrent malignant disease diagnosed or treated in the last 2 years except for adequately treated in situ carcinoma of the cervix, basal or squamous skin cell carcinoma, or in situ transitional bladder cell carcinoma,

⁃ At least three weeks since last chemotherapy, immunotherapy and two weeks for any other pharmacological treatment and/or radiotherapy,

⁃ Recovery to grade ≤ 1 from any adverse event (AE) derived from previous treatment (excluding alopecia of any grade, non-painful peripheral neuropathy grade ≤ 2 and endocrine-related grade ≤ 2 requiring treatment or hormone replacement) (according to NCI-CTCAE, version 5.0). For patients previously treated by radiotherapy, they must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis,

⁃ Women of childbearing potential must have a negative serum pregnancy test within 72 hours prior to receiving the first dose of study medication. Both women and men must agree to use 2 medically acceptable methods of contraception throughout the treatment period and for 6 months after discontinuation of treatment. Subjects of childbearing potential are those who have not been surgically sterilized or have not been free from menses for ≥ 1 year,

⁃ Voluntary signed and dated written informed consents prior to any specific study procedure,

⁃ Patients with a social security in compliance with the French Law.