Gravar-mail: A Phase 2 Trial of R1507, a Monoclonal Antibody to the Insulin-Like Growth Factor-1 Receptor (IGF-1R), in Patients With Recurrent or Refractory Rhabdomyosarcoma, Osteosarcoma, Synovial Sarcoma, and Other Soft Tissue Sarcomas: Results of a Sarcoma Alliance for Research Through Collaboration Study