RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Monoclonal antibodies such as gemtuzumab ozogamicin can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells. Combining more than one drug or combining monoclonal antibody with chemotherapy may kill more cancer cells. It is not yet known which treatment regimen is more effective for acute myelogenous leukemia.