A Study of Pemetrexed in Children With Recurrent Cancer

Inclusion Criteria: * Patients must have osteosarcoma, Ewing's sarcoma, medulloblastoma, neuroblastoma, rhabdomyosarcoma, ependymoma or high-grade non-brainstem glioma * Measurable disease * Eastern Cooperative Oncology Group (ECOG) performance 0,1,2 * Adequate renal, liver and bone marrow function * Patient's current disease state must be one with no known curative therapy or therapy proven to prolong survival with an acceptable quality of life Exclusion Criteria: * Growth factors that support platelet or white cell number or function must not have been administered within the last 7 days prior to enrollment (14 days if Neulasta) * Patients with central nervous system (CNS) tumors who have not been on a stable or decreasing dose of dexamethasone or other corticosteroid for 7 days prior to enrollment * Patients with uncontrolled infection * Patients who have received pemetrexed previously * Patients with pleural effusions or ascites