Ceralasertib is an orally available inhibitor of ataxia telangiectasia and rad3 related (ATR) kinase. Ceralasertib selectively inhibits ATR activity by blocking the downstream phosphorylation of the serine threonine protein kinase CHK1. This prevents ATR-
(S)-Ceralasertib is a potent and selective inhibitor of sulfoximine morpholinopyrimidine ATR with excellent preclinical physicochemical and pharmacokinetic (PK) characteristics. .