Gemtuzumab ozogamicin, fludarabine, cytarabine and cyclosporine combination regimen in patients with CD33+ primary resistant or relapsed acute myeloid leukemia.

Clinical resistance to gemtuzumab ozogamicin (Mylotarg) in acute myeloid leukemia (AML) is associated with blast multidrug resistance (MDR) phenotype. A Phase II study of Mylotarg, fludarabine, ara-C and the MDR-modifier, cyclosporine (CSA) (MFAC) was conducted in 32 patients with primary resistant (11, 34%) or relapsed (21, 66%) AML. Nine (28%) patients obtained complete remission (CR), two (6%) CR with incomplete platelet recovery. Overall median survival was 5.3 months, 12-month survival rate 19%. Fourteen patients (44%) developed grade 3/4 hyperbilirubinemia; six (18%) grade 3/4 hepatic transaminitis; three (9%) hepatic veno-occlusive disease (VOD). CSA inclusion in gemtuzumab ozogamicin-based regimens is feasible. MFAC is an effective regimen for refractory AML.