Pretreatment of leukemic cells with low-dose decitabine markedly enhances the cytotoxicity of gemtuzumab ozogamicin

Prognosis in relapsed/refractory acute myeloid leukemia (AML) is poor due to drug resistance. Gemtuzumab ozogamicin (GO) is a molecularly targeted drug, which consists of anti-CD33 antibody and calicheamicin. The high expression of CD33 antigen on most AML cells and exceptionally marked cytotoxicity of calicheamicin have attracted strong interest in GO, but clinical results on GO monotherapy have been disappointing, and methods of overcoming resistance to GO have accordingly been sought.