An orally bioavailable inhibitor of cell division cycle 7 (cell division cycle 7-related protein kinase; CDC7), with potential antineoplastic activity. Upon administration, simurosertib binds to and inhibits CDC7; this prevents the initiation of DNA replication during mitosis, which causes cell cycle arrest and induces apoptosis. This inhibits cell growth in CDC7-overexpressing tumor cells. CDC7, a serine/threonine kinase and cell division cycle protein, is overexpressed in a variety of cancers and plays a key role in the activation of DNA replication and the regulation of cell cycle progression.