Ziftomenib, a potent, selective inhibitor that binds menin at the lysine methyltransferase 2 interaction site, has demonstrated promising clinical activity with manageable toxicity in heavily pretreated patients with acute myeloid leukemia (AML) and nucleophosmin 1 mutations. This phase 1, open-label study characterized the absorption, metabolism, excretion, and bioavailability of ziftomenib in healthy men and comprised two parts. In part A, a single oral dose of ziftomenib 400 mg (containing 250 μCi [