10018 Background: With longer followup, the addition of muramyl tripeptide (MTP) to chemotherapy has been shown to improve overall survival in patients with non-metastatic osteosarcoma (OS). We report the results of MTP addition to chemotherapy for patients with metastatic OS. Methods: Intergroup-0133 was a prospective randomized trial for the treatment of newly diagnosed patients with OS. We compared three drug chemotherapy with cisplatin, doxorubicin, and high-dose methotrexate (Regimen A) to the same three drugs with the addition of ifosfamide (Regimen B). We evaluated the addition of MTP to chemotherapy. We report herein the first analysis of 91 patients with metastatic OS at presentation. Outcome measures included event free survival (EFS) and survival. Results: Five-year EFS for patients who received MTP (n=46) was 42% versus 26% for those who did not (n=45), p=0.38. The 5-year overall survival for patients who received MTP versus no MTP was 53% and 40% respectively (p=0.36). The comparison of Regim...