A study to assess the general safety and effect of gemtuzumab ozogamicin (MYLOTARG™) on the heart of patients with CD33-positive acute myeloid leukemia and to see how the drug moves through the body. A single-arm, open-label, phase 4 study evaluating QT interval, pharmacokinetics, and safety of gemtuzumab
ozogamicin (MYLOTARG™) as a single-agent regimen in patients with relapsed or refractory CD33-positive acute myeloid leukemia