Cortes JE, et al. - Bosutinib is a potent dual SRC/ABL kinase inhibitor approved for adults with Philadelphia chromosome–positive chronic myeloid leukemia (CML) resistant and /or intolerant to prior therapy. This study represents efficacy and safety trial of bosutinib versus imatinib for first-line treatment of chronic-phase CML. Treatment with bosutinib versus imatinib resulted in significantly higher rates of major molecular response (MMR) and complete cytogenetic response (CCyR) and achievement of faster responses. With bosutinib, GI events and transaminase elevations were more commonly detected, a finding consistent with the known safety profile of bosutinib. The results indicate that bosutinib may be an effective first-line treatment for chronic-phase CML.