(R)-AMG-193 is an isomer of AMG 193. AMG 193 is an orally active MTA-cooperative PRMT5 inhibitor with antitumor activity. AMG 193, when complexed with MTA, preferentially inhibits the growth of MTAP-deficient tumor cells by inhibiting PRMT5 ( IC 50 =0.107 μM), thereby protecting normal cells with wild-type MTAP.