In a deal potentially worth up to $15.2 billion, Jiangsu Hengrui Pharmaceuticals Co. Ltd. is joining efforts with Bristol Myers Squibb Co. to advance 13 early development programs in the fields of oncology, hematology and immunology. Shanghai-based Hengrui will hold exclusive rights in mainland China, Hong Kong and Macau, while Princeton, N.J.-based BMS will hold exclusive rights in the rest of the world. The deal includes four oncology/hematology assets from Hengrui, four immunology assets from BMS, and five assets that the two companies will jointly discover and develop.