Identification of Structurally Novel KRAS Inhibitors through Covalent DNA-Encoded Library Screening.

Covalent inhibition of the KRAS oncoprotein has emerged as a promising therapeutic approach for the treatment of nonsmall cell lung cancer (NSCLC). The identification of KRAS inhibitors has typically relied on the high-throughput screening (HTS) of libraries of cysteine-reactive small molecules or on the attachment of cysteine-reactive warheads to noncovalent binders of KRAS. Such screening approaches have historically been limited in the size and diversity of molecules that could be effectively screened. DNA-encoded library (DEL) screening has emerged as a promising approach to accelerate the preparation and screening of incredibly large and diverse chemical libraries. Here, we describe the design and synthesis of a covalent DEL to screen ∼16 million compounds against KRAS. We additionally describe the hit identification, validation, and structure-based optimization that culminated in the identification of a series of structurally novel, potent, and selective covalent inhibitors of KRAS with good pharmacokinetic profiles and promising in vivo pharmacodynamic effects.