Changes in the activity of the GPx-1 anti-oxidant selenoenzyme in mononuclear cells following imatinib treatment.

Imatinib inhibits the ABL tyrosine kinase and is effective for the treatment of chronic myeloid leukemia (CML). ABL activates GPx-1, an enzyme associated with protection against oxidative DNA damage and disease. Enzyme activity was assessed in sample pairs consisting of mononuclear cells obtained from patients before and after imatinib therapy. Control sample sets obtained from patients not receiving imatinib showed little change in GPx activity over a several month interval. Five of 7 sample sets obtained from imatinib-receiving patients showed changes in GPx activity greater than 30%. One sample decreased 42% while 4 others increased 33-208%. Patients with the largest increase in activity were female and had the lowest baseline levels of GPx activity. Changes in GPx activity may influence the clinical outcome of patients being treated for CML.