Critères d'inclusion : 1. Histologically confirmed Ewing sarcoma.
2. Disease recurrence or progression after completion of first line treatment OR
Refractory disease, defined by progression during first line treatment or within 12 weeks of its completion. Disease progression will be based on Response Evaluation Criteria In Solid Tumors (RECIST). The appearance of new bone lesions on bone scan will require confirmation with cross-sectional imaging.
3. Soft tissue disease component evaluable by cross-sectional imaging. Patients with bone disease without a measurable soft tissue component or bone marrow disease only will be eligible for the study but will not contribute to the phase II primary outcome measure.
4. Age ≥4 years and <50 years.
5. Patient assessed as medically fit to receive cytotoxic chemotherapy.
6. Documented negative pregnancy test fr female patients of childbearing potential.
7. Patient agrees to use effective contraception during therapy and for 12 months, after last trial treatment, where applicable.
8. Written informed consent from the patient and/or legal guardian.
Critères de non-inclusion : 1.Bone marrow infiltration resulting in absolute neutrophil count (ANC) < 1.0 x 109/l or platelets <75 x 109/l
2.Cytotoxic chemotherapy or other investigational medicinal product (IMP) within previosu two weeks.
3.Myeloablative therapy within previous eight weeks.
4.Radiotherapy to target lesion within previous six weeks.
5.Pregnant or breastfeeding women.
6.Follow-up not possible due to social, geographic or psychological reasons.