Imatinib mesylate (STI 571)--a new oral target therapy for chronic myelogenous leukemia (CML)

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Chronic myelogenous leukemia (CML) is characterized by specific cytogenetic abnormalities, notably the Philadelphia chromosome.
• The BCR-ABL fusion gene, a product of this abnormality, encodes a constitutively active tyrosine kinase, driving leukemogenesis.

Purpose of the Study:

• To review the significance of cytogenetic abnormalities in CML.
• To evaluate the efficacy of imatinib mesylate, a targeted tyrosine kinase inhibitor, across various CML phases and related malignancies.
• To discuss mechanisms of resistance to imatinib and strategies to overcome them.

Main Methods:

• Review of published clinical trial data and scientific literature on imatinib mesylate.
• Analysis of treatment outcomes in chronic phase, accelerated phase, and blast crisis CML.
• Examination of results in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL).

Main Results:

• Imatinib mesylate demonstrates significant efficacy in chronic phase CML, including in interferon-resistant and newly diagnosed patients.
• Positive responses are observed in accelerated phase and blast crisis CML, as well as post-allogeneic stem cell transplantation relapse.
• Efficacy is also noted in Ph+ acute lymphoblastic leukemia.

Conclusions:

• Imatinib mesylate represents a breakthrough targeted therapy for BCR-ABL-driven leukemias.
• Understanding and addressing resistance mechanisms are crucial for long-term treatment success.
• Future strategies include dose escalation, combination therapies, and novel drug development.