BOSTON--(BUSINESS WIRE)--Verastem, Inc. (NASDAQ:VSTM), focused on discovering and developing drugs to treat cancer by the targeted killing of cancer stem cells, today announced that Joanna Horobin, M.B., Ch.B., Chief Medical Officer (CMO), will transition to the role of Senior Advisor. In conjunction with this transition, the Company also announced that Lou Vaickus, MD, FACP will be named Interim CMO. These changes will become effective on July 1, 2015.