Inclusion Criteria:

- patients >=2 years of age;

- progressive, recurrent or refractory Ewing's sarcoma, or recurrent or refractory
osteosarcoma, synovial sarcoma, rhabdomyosarcoma, or other sarcomas of the following
sub-types: alveolar soft part sarcoma, desmoplastic small round cell tumor,
extraskeletal myxoid chondrosarcoma, clear cell sarcoma and myxoid liposarcoma.

Exclusion Criteria:

- clinically significant unrelated systemic illness which would compromise the
patient's ability to tolerate the investigational agent, or interfere with the study
procedures or results;

- known hypersensitivity to any of the components of R1507 or prior hypersensitivity
reactions to monoclonal antibodies;

- current or previous treatment (within last 6 months) with chronic pharmacological
doses of corticosteroids, immunosuppressive agents or medications that inactivate or
may interfere with the pharmacological activity of R1507;

- current or prior therapy with IGF inhibitor (monoclonal or specific kinase
inhibitor);

- history of solid organ transplant;

- other malignant disease diagnosed within the previous 5 years, excluding
intra-epithelial cervical neoplasia or non-melanoma skin cancer.