Multicentre, randomised, open-label, phase II trial, with 2 parallel groups. After pre-operative chemotherapy and surgery of the primary tumour and lung metastases (if applicable), patients presenting high-risk osteosarcoma (defined as metastatic osteosarcoma at diagnosis or localised osteosarcoma with poor histological response) will be randomised between 2 arms:~Control arm: post-operative chemotherapy alone (with regimens adapted to the age of patient)~Experimental arm : post-operative chemotherapy combined with mifamurtide~This randomised trial is part of a study recruiting all patients ≤50 years old with a newly diagnosed high-grade osteosarcoma.
Trial evaluating the impact on efficacy of mifamurtide as add-on treatment to post-operative chemotherapy compared to post-operative chemotherapy alone in first-line treatment of patients with high-risk osteosarcoma (defined as metastatic osteosarcoma at diagnosis or localised osteosarcoma with poor histological response).