Structure-Based Design of a Novel Covalent 4-(1-Methylindol-3-yl)pyrimidin-2-amine Series Targeting FGFR2 Resistance Mutations. (PubMed, J Med Chem)
While approved pan-FGFR inhibitors provide clinical benefit, their durability is limited by acquired, often polyclonal, on-target resistance mutations affecting key regions of the FGFR2 kinase domain, including the gatekeeper residue (V565), molecular brake residues (N550, E566, K642), and other key variants...Given FGFR2-associated toxicities and the need for subtype selectivity, FGFR4 inhibition was prioritized as a selectivity determinant, while sparing FGFR1 was considered less critical. Guided by structure-based drug design, a reversible aminopyrimidine screening hit was optimized into a novel covalent inhibitor series active against FGFR2 wild-type and clinically relevant resistance mutations. An advanced lead 13 showed favorable potency, ADME properties, and demonstrated proof-of-concept in vivo efficacy in an FGFR2-amplified xenograft model comparable with the standard of care.