Denosumab in Treating Patients With Recurrent or Refractory Osteosarcoma

PRIMARY OBJECTIVES: I. To determine whether denosumab therapy either increases the disease control rate at 4 months in patients with recurrent measurable osteosarcoma as compared to historical Children's Oncology Group (COG) experience or denosumab therapy produces an objective response rate greater than 5% (Cohort 1). II. To determine whether denosumab therapy increases the disease control rate at 12 months in patients with recurrent resected osteosarcoma as compared to historical COG experience (Cohort 2). SECONDARY OBJECTIVES: I. To investigate the pharmacokinetics (PK) and pharmacodynamics (PD) of denosumab in subjects with recurrent osteosarcoma. II. To describe the tolerability of denosumab in subjects with recurrent osteosarcoma. III. To report the disease control rate and objective response rate for patients with recurrent osteosarcoma limited to bone. IV. To investigate biological markers potentially associated with response to denosumab in patients with recurrent osteosarcoma. OUTLINE: Patients receive denosumab subcutaneously (SC) on day 1 (days 1, 8, and 15 of course 1 only). Treatment repeats every 4 weeks (28 days) for up to 24 months or 26 courses, whichever occurs first, in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up monthly for 1 year.