This study will examine the safety profile of vadastuximab talirine (SGN-CD33A) administered
as a single agent and in combination with a hypomethylating agent (HMA). The main purpose of
the study is to find the maximum tolerated dose (MTD, which is the highest dose that does not
cause unacceptable side effects) of SGN-CD33A in patients with acute myeloid leukemia (AML).
The MTD will be determined by observing the dose-limiting toxicities (the side effects that
prevent further increases in dose) of SGN-CD33A. In addition, the pharmacokinetic profile and
anti-leukemia activity of SGN-CD33A will be assessed.