– Prexasertib lactate is the lactate salt form of Prexasertib and functions as a selective, ATP-competitive second-generation checkpoint kinase 1 (CHK1) inhibitor with a Ki of 0.9 nM and an IC50 of less than 1 nM. It also inhibits CHK2 (IC50 = 8 nM) and RSK1 (IC50 = 9 nM). This compound induces double-strand DNA breaks and replication stress, leading to apoptosis (cell death), and exhibits antitumor activity.