Multi-drug resistance (MDR) protein expression is associated with reduced gemtuzumab ozogamicin (Mylotarg) activity. Both cyclosporine-A (CSA) and liposome-encapsulated daunorubicin, DaunoXome (DNX) may reduce the negative impact of MDR. A gemtuzumab ozogamicin, DNX, cytarabine (ara-C) and CSA (MDAC) regimen was piloted in patients with refractory acute myelogenous leukemia (AML) (relapsed 10, primary refractory 1) (median age 37 years (16-67)). One (9%) patient achieved a transient CR, one CRp. Grade 3/4 toxicities included sepsis (seven patients; 63%); hyperbilirubinemia (six patients; 54%), with transaminitis in one patient; mucositis (three patients; 27%). The inclusion of CSA in a gemtuzumab ozogamicin-containing regimen is feasible. The MDAC regimen was associated with significant toxicity in a cohort of patients with very advanced AML.