In Vitro: RMC-4550 is an allosteric inhibitor of SHP2 and stabilizes the auto-inhibited conformation of wild-type SHP2 enzyme, with a mode of inhibition similar to SHP099. Consistent with an allosteric mode of inhibition, RMC-4550 inhibits the activity of full-length wild-type SHP2 enzyme activated by a di-phosphotyrosine peptide, but lacks activity against the free catalytic domain of SHP2.