DFMO Maintenance for Patients With Relapsed/Refractory Ewing Sarcoma or Osteosarcoma

Inclusion Criteria:

• Patients < 40 years of age at the time of enrollment

• Diagnosis of relapsed osteosarcoma or relapsed Ewing sarcoma who have completed allplanned therapy for their relapse, as described in the protocol, and have noevidence of disease

• Patients must have a performance status corresponding to Eastern CooperativeOncology Group (ECOG) scores of 0, 1, or 2

• Myelosuppressive chemotherapy: At least 14 days must have elapsed since completionof myelosuppressive therapy

• Monoclonal antibodies: At least 21 days must have elapsed from infusion of last doseof antibody, and toxicity related to prior antibody therapy must be recovered toGrade < 2

• Biologic therapy (defined as anti-cancer agents not known to be myelosuppressive):At least 7 days after the last dose of agent

• Radiation therapy: At least 14 days must have elapsed after local External BeamRadiation Therapy (XRT), at least 90 days after Total Body Irradiation (TBI),craniospinal XRT or if radiation to greater than 50% of the pelvis, and at least 42days if other substantial bone marrow radiation

• Adequate bone marrow function defined as:

• Peripheral absolute neutrophil count (ANC) greater or equal to 750/microliter

• Platelet count greater or equal to 75,000/microliter (transfusion independent)

• Adequate renal function defined by serum creatinine based on age and gender (seeprotocol)

• Adequate liver function defined as:

• Total bilirubin ≤ 1.5 x the upper limit of normal (ULN) for age AND

• SGPT (ALT) ≤ 5.0 x ULN for age. For this study the ULN is 45 U/L

Exclusion Criteria:

• Pregnant or breastfeeding females. Men and women of childbearing potential and theirpartners must agree to use adequate contraception while enrolled on this study.Based on the teratogenic potential of the agent, pregnant women will be excludedfrom this study. Because of potential risks to breastfed infants due to drugmetabolites that could be excreted in breast milk, female patients who are lactatingmust agree to stop breastfeeding or will otherwise be excluded from this study.Females of childbearing potential must have a negative pregnancy test to be eligiblefor this study

• Patients must not have an uncontrolled infection

• Patients with a significant intercurrent illness (any ongoing serious medicalproblem unrelated to cancer or its treatment) that is not covered by the detailedexclusion criteria and that is expected to interfere with the action of study agentsor to significantly increase the severity of the toxicities experienced from studytreatment are not eligible