Rigel Pharmaceuticals, Inc. and Bristol-Myers Squibb have entered into a collaboration agreement for the discovery, development and commercialization of cancer immunotherapies based on Rigel’s portfolio of small molecule TGF beta receptor kinase inhibitors. TGF beta can promote tumor growth and broadly suppress the immune system. The collaboration will focus on developing a new class of therapeutics aimed at increasing the immune system’s activity against various cancers, either as m...