Methods of treatment and pharmaceutical combinations are provided for the treatment of acute leukemia, such as acute myelogenous leukemia, and myelodysplastic syndrome. The methods of treatment and pharmaceutical combinations employ an anti-CD33 cytotoxic conjugate in combination with at least one compound selected from the group consisting of an anthracycline and a pyrimidine or purine nucleoside analog. Preferred methods of treatment and pharmaceutical combinations employ gemtuzumab ozogamicin, daunorubicin, and cytarabine.