Tucidinostat Plus Apatinib for Advanced Osteosarcoma

Inclusion Criteria: 1. Age ≥10 years, ≤ 75 years; 2. Histologically confirmed Advanced classic osteosarcoma with unresectable recurrence or metastatic disease ； 3. Prior treatment consisted of standard chemotherapy agents including doxorubicin, cisplatin, methotrexate, and ifosfamide; 4. Eastern Collaborative Oncology Group (ECOG) 0\~2； 5. Tumor size is measurable according to RECIST1.1 criteria； 6. Adequate organ function； 7. Life expectancy is more than 3 months； 8. Willing and able to provide written informed consent. Exclusion Criteria: 1. Previously exposed to histone deacetylase inhibitors or angiogenesis inhibitors; 2. Urine protein≥ ++; 3. FBG\>10mmol/L; 4. Uncontrolled blodd pressure (ystolic blood pressure \> 150 mmHg and/or diastolic blood pressure \> 90 mmHg); 5. Known active CNS metastases and/or carcinomatous meningitis; 6. Not able to take medicine orally; 7. Coagulant function abnormality (PT\>16s, APTT\> 43s, TT\>21s, FIB）\<2g/L); 8. Uncontrolled clinically significant systemic diseases, including active infection, unstable angina, angina occurred within 3 months,≥ NYHA II congestive heart failure, myocardial infarction occurred within 6 months, severe arrhythmia, liver, kidney, or metabolic disease; 9. Major surgery received or severe traumatic injury, fracture, or ulcer occurred within 4 weeks of the first dose of study medication.