Rigosertib (ON-01910) is a non-ATP-competitive inhibitor of PLK1 with IC50 of 9 nM in a cell-free assay. It shows 30-fold greater selectivity against Plk2 and no activity to Plk3. Rigosertib inhibits PI3K/Akt pathway and activates oxidative stress signals. Rigosertib induces apoptosis in various cancer cells. Phase 3.