Dainippon Sumitomo Pharma has agreed to acquire Boston Biomedical Inc. for $200 million. Based in Norwood, Mass., BBI is developing two small-molecule drugs that work by targeting cancer stem cells. One, BBI608, is being prepared for a Phase III clinical trial as a colorectal cancer treatment and is in Phase Ib and II trials for various solid tumors. The other, BBI503, is in Phase I trials for solid tumors. Under the deal, BBI’s six shareholders also can get up to $540 million in developmental milestone payments. Dainippon Sumitomo licensed Japanese rights to BBI608 in March 2011.