KT-253, A Novel MDM2 Degrader and p53 Stabilizer, Has Superior Potency and Efficacy Than MDM2 Small Molecule Inhibitors

Abstract Murine double minute 2 (MDM2) is an E3 ligase that inhibits the tumor suppressor protein p53. Clinical trials employing small-molecule MDM2/p53 interaction inhibitors (SMIs) have demonstrated limited activity, underscoring an unmet need for a better approach to target MDM2. KT 253 is a highly potent and selective heterobifunctional degrader that overcomes the MDM2 feedback loop seen with SMIs and induces apoptosis in a range of hematologic and solid tumor lines. A single intravenous dose of KT 253 triggered rapid apoptosis and sustained tumor regression in p53 wild-type acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) xenograft models. Additionally, a single intravenous dose of KT 253 in combination with standard-of-care (SoC) venetoclax, overcame venetoclax resistance in an AML xenograft model. The data herein define the therapeutic potential of KT-253 and support its clinical development in a range of hematologic and solid p53 wild-type (WT) malignancies, as a monotherapy and in combination with SoC agents.