Silmitasertib (CX-4945) is a potent and selective orally bioavailable small molecule inhibitor of Casein kinase II (CK2). The antiproliferative activity of CX-4945 against cancer cells correlated with expression levels of the CK2α catalytic subunit. CX-4945 caused cell-cycle arrest and selectively induced apoptosis in cancer cells relative to normal cells. When administered orally in murine xenograft models, CX-4945 was well tolerated and demonstrated robust antitumor activity. Senhwa Biosciences is developing silmitasertib for the treatment of cholangiocarcinoma, other solid tumours, Castleman's disease (giant lymph node hyperplasia) and multiple myeloma. The compound was originally developed by Cylene Pharmaceuticals. Phase Ib/II development is underway in the US and South Korea for the treatment of cholangiocarcinoma, and development in the remaining indications is at the phase I stage. As at July 2016, no recent reports of development had been identified for phase-I development in Giant-lymph-node-hyperplasia in USA (PO, Capsule), phase-I development in Multiple-myeloma in USA (PO, Capsule), phase-I development in Solid-tumours (Late-stage disease) in USA (PO, Capsule).