Structure of the Abl protein kinase catalytic domain bound to a first-generation therapeutic, imatinib (PDB ID 1IEP; orange), which inspired medicinal chemists at Novartis to design an even more effective second-generation agent, nilotinib (PDB ID 3CS9; green). Both are U.S. FDA approved drugs used for treatment of chronic myeloid leukemiaRutgers, The State University of New Jersey