XL413 is a selective inhibitor of the serine-threonine kinase CDC7 (cell division cycle 7 homolog), a regulator of cell cycle checkpoint control that has been implicated in protecting tumor cells from apoptotic cell death during replication stress. XL413 has an IC50 of 3.4 nM for CDC7, compared to 215 nM, 42 nM and 18 nM for CK2, PIM1 and pMCM2, respectively. XL413 caused significant tumor growth regression in rodent models, causing cell cycle arrest in the late S to G2 phase.