A Study of SGT-53 in Children With Refractory or Recurrent Solid Tumors

Inclusion Criteria: * All patients and/or their parents or legally authorized representatives must sign a written informed consent. * Patients must be \> than 12 months and ≤ 21 years of age at the time of study enrollment. * Body surface Area (For Dose Level -1): Patients must be ≥ 0.38 m² at the time of study enrollment. * Patients with relapsed or refractory solid tumors (excluding primary central nervous system tumors) are eligible. Patients must have had histologic verification of malignancy at original diagnosis or relapse. * Patients must have either measurable or evaluable disease. * Patient's current disease state must be one for which there is no known curative therapy or therapy proven to prolong survival with an acceptable quality of life. * Karnofsky ≥ 50% for patients \> 16 years of age and Lansky ≥ 50 for patients ≤ 16 years of age. * Patients must have fully recovered from the acute toxic effects of all prior anti-cancer chemotherapy: * At least 21 days after the last dose of myelosuppressive chemotherapy (42 days if prior nitrosourea). * At least 14 days after the last dose of a long-acting growth factor (e.g. Neulasta) or 7 days for short-acting growth factor. * At least 7 days after the last dose of a biologic agent. * At least 42 days after the completion of any type of immunotherapy, e.g. tumor vaccines. * At least 3 half-lives of the antibody after the last dose of a monoclonal antibody. * At least 14 days after local palliative XRT (small …