Evaluating QTc, PK, Safety of Gemtuzumab Ozogamicin (GO) in Patients With CD33+ R/R AML

Inclusion Criteria

* Refractory or relapsed (ie, bone marrow blasts \>5%) CD33-positive AML.
* Age \>=12 years.
* Eastern Cooperative Oncology Group (ECOG) Performance Status 0 to 2.
* Initial peripheral white blood cells (WBC) counts \>=30,000/mL; patients with a higher WBC count should undergo cytoreduction.
* Adequate renal/hepatic functions

Exclusion Criteria

* Patients with prior treatment with gemtuzumab ozogamicin (GO).
* Patients with prior history of VOD/SOS.
* Prior HSCT is not allowed, if it was conducted within 2 months prior to study enrollment.
* Patients with known active central nervous system (CNS) leukemia.
* Uncontrolled or active infectious status.
* Uncontrolled cardiac dysrhythmias of NCI CTCAE Grade 2, uncontrolled atrial fibrillation of any grade.
* Sero-positivity to human immunodeficieny virus (HIV).
* Active hepatitis B or hepatitis C infection
* Chemotherapy, radiotherapy, or other anti-cancer therapy (except hydroxyurea as cytoreduction) within 2 weeks prior to enrollment in the study.
* Major surgery within 4 weeks prior to enrollment.
* QTc interval \>470 milliseconds (msec) using the Fridericia (QTcF), family or personal history of long or short QT syndrome, Brugada syndrome or known history of QTc prolongation, or Torsade de Pointes (TdP).
* The use of medications known to predispose to Torsades de Pointes within 2 weeks prior to enrollment
* History of allergic reactions attributed to compounds of similar chemical or biologic composition to gemtuzumab ozogamicin (GO).