Sustained complete hematologic remission after administration of the tyrosine kinase inhibitor imatinib mesylate in a patient with refractory, secondary AML.

Imatinib mesylate, a tyrosine kinase inhibitor targeting bcr-abl, platelet-derived growth factor receptor (PDGF-R), and c-Kit, effectively induces hematologic and cytogenetic remissions in bcr-abl(+) chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL) with only mild to moderate side effects. Here, we describe the successful treatment of a 64-year-old man with c-Kit(+) secondary acute myeloid leukemia (AML) refractory to standard chemotherapy. Upon 2 weeks of imatinib mesylate administration, the patient achieved a complete hematologic remission in peripheral blood. In addition, complete clearance of leukemic blasts in bone marrow and a significant cytogenetic response lasting for more than 5 months was observed. Sequence analysis of exons 2, 8, 10, 11, and 17 of the c-Kit receptor did not reveal structural alterations as previously described in a subset of AML cases. This is the first report of complete remission achieved upon administration of imatinib mesylate in a patient with highly refractory, secondary AML.