Imatinib Active Not Recruiting Phase 2 Trials for Recurrent Adult Acute Lymphoblastic Leukemia / Blastic Phase Chronic Myelogenous Leukemia / Relapsing Chronic Myelogenous Leukemia / Philadelphia Chromosome Positive Adult Precursor Acute Lymphoblastic Leukemia / Philadelphia Chromosome Positive Childhood Precursor Acute Lymphoblastic Leukemia / Recurrent Childhood Acute Lymphoblastic Leukemia / Chronic Myelogenous Leukemia, BCR-ABL1 Positive / Childhood Acute Lymphoblastic Leukemia in Remission / Chronic Phase Chronic Myelogenous Leukemia / Adult Acute Lymphoblastic Leukemia in Remission Treatment