Comparison of MAPI+Camrelizumab Versus API+Apatinib Versus MAPI in Patients With a Poor Response to Preoperative Chemotherapy for Newly Diagnosed High-grade Osteosarcoma

Inclusion Criteria: * Histologically confirmed high-grade osteosarcoma, including second malignancies * Tumor (primary, metastatic, or both) resectable OR is expected to become resectable after neoadjuvant induction chemotherapy * Suitable for neoadjuvant chemotherapy and adjuvant chemotherapy * Performance status - Lansky 50-100% (for patients under 16 years of age); Performance status - WHO or ECOG 0-2 with a life expectancy \>3 months * normal cardiac function (shortening fraction \>28%), normal hearing, normal bone marrow as shown by an absolute neutrophil count of at least 1·5 × 10⁹ cells per L (or a white blood cell count of at least 3 × 10⁹ cells per L if neutrophil count is not available), and a platelet count of at least 100 000 platelets per μL * Patients were also required to have a serum bilirubin concentration of at most less than 1·5 times the upper limit of normal and a normal creatinine concentration for their age as per protocol * Women of child-bearing potential had to take adequate contraceptive measures and have a negative pregnancy test within 7 days of study entry. Exclusion Criteria: * patients who have recieved anti-angiogenic TKIs or anti-PD-1/PD-L1 antibodies * allergy to chemotherapy or apatinib or camrelizumab * other severe illness (eg, psychosis or previous history of cardiovascular disease) * symptomatic or known CNS metastases * previous or concurrent second primary malignant tumours * had uncontrolled complications such as diabetes mellitus, coagulation disorders, urine protein ≥ ++, and so on * had other infections or wounds * pregnant or breastfeeding.