Elevations of creatine kinase in patients treated with imatinib mesylate (Gleevec).

Imatinib mesylate is used with increasing frequency and duration for the treatment of chronic myelogenous leukemia (CML), gastrointestinal stromal tumor (GIST), and other neoplastic conditions. Although muscular complaints are common, elevations of creatine kinase (CK) are listed as <1% in the product label. We describe here a case of rhabdomyolysis likely related to imatinib as well as the results of a prospective evaluation of CK levels in a cohort of patients on imatinib for CML or GIST. We found a high prevalence of CK abnormalities in this group and believe that CKs should be monitored during therapy with imatinib.