Philadelphia chromosome-positive acute lymphoblastic leukemia: current treatment and future perspectives

The Philadelphia chromosome (Ph) is the most common cytogenetic abnormality associated with adult acute lymphoblastic leukemia (ALL). Before the advent of tyrosine kinase inhibitors (TKIs), Ph-positive ALL carried a dismal prognosis and was characterized by a poor response to most chemotherapy combinations, short remission durations, and poor survival rates. Outcomes for patients with Ph-positive ALL improved substantially with the introduction of TKIs, and the TKI imatinib induced complete remissions in >95% of patients with newly diagnosed Ph-positive ALL when it was combined with chemotherapy. However, imatinib resistance remains a problem in a substantial proportion of patients with Ph-positive ALL, and multiple molecular mechanisms that contribute to imatinib resistance have been identified. Second-generation TKIs (eg, dasatinib and nilotinib) have demonstrated promising efficacy in the treatment of imatinib-resistant, Ph-positive ALL. Future strategies for Ph-positive ALL include novel, molecularly targeted treatment modalities and further evaluations of TKIs in combination with established antileukemic agents. For this article, the authors reviewed past, current, and future treatment approaches for adult and elderly patients with Ph-positive ALL with a focus on TKIs and combined chemotherapeutic regimens.