A substance being studied in the treatment of cancer. It blocks certain proteins that are needed for cell growth and may kill cancer cells. ON 01910.Na is a type of protein kinase inhibitor and a type of benzyl styryl sulfone analog.

The sodium salt form of rigosertib, a synthetic benzyl styryl sulfone analogue and Ras mimetic, with potential antineoplastic activity. Upon administration, rigosertib targets and binds to Ras-binding domain (RBD) found in many Ras effector proteins, including Raf kinase and phosphatidylinositol 3-kinase (PI3K). This prevents Ras from binding to its targets and inhibits Ras-mediated signaling pathways, including Ras/Raf/Erk, Ras/CRAF/polo-like kinase1 (Plk1), and Ras/ PI3K/Akt signaling pathways. This induces cell cycle arrest and apoptosis and inhibits proliferation in a variety of susceptible tumor cells.