 The trial seeks to analyze progression free survival PFS, measured as PFS rate at 4 months, in patients with metastatic osteosarcoma who have previously received the most active drugs in this disease methotrexate, cisplatin, adriamycin and ifosfamide. The treatment schedule consists of a maximum of 6 cycles of 3 weeks of gemcitabinerapamycin. Gemcitabine is given at 800 mgm2 in days 1 and 8 in cycles of 21 days. Rapamycin is given at 5 mg per day during treatment duration. 