Study Evaluating SKI-606 (Bosutinib) In Philadelphia Chromosome Positive Leukemias

This is an open-label, continuous daily dosing, two-part safety and efficacy study of SKI-606 (bosutinib) in Philadelphia chromosome positive leukemias (Ph+). Part 1 is a dose-escalation study in chronic phase Chronic Myelogenous Leukemia (CML) subjects to establish the maximum tolerated dose (MTD) in this subject population. Part 2 has begun after the completion of Part 1 and after a dose has been established for the compound in chronic phase subjects. Part 2 is a study of the the efficacy of 500mg daily oral SKI-606 (bosutinib) in patients with all phases of Ph+ CML and Ph+ Acute Lymphocytic Leukemia (ALL). The protocol will test the hypotheses that oral daily dosing of bosutinib at 500 mg will attain (1) Major Cytogenetic Response (MCyR) in chronic phase CML patients and (2) Overall Hematological Response (OHR) in advanced leukemia patients. Each phase of the disease will be evaluated as a separate cohort.