text: The classic example of targeted development is imatinib mesylate (Gleevec), a small molecule which inhibits a signaling molecule kinase. The genetic abnormality causing chronic myelogenous leukemia (CML) has been known for a long time to be a chromosomal translocation creating an abnormal fusion protein, kinase BCR-ABL, which signals aberrantly, leading to uncontrolled proliferation of the leukemia cells. Imatinib precisely inhibits this kinase. Unlike so many other anti-cancer agents, this pharmaceutical was no accident. Brian Druker, working in Oregon Health & Science University, had extensively researched the abnormal enzyme kinase in CML. He reasoned that precisely inhibiting this kinase with a drug would control the disease and have little effect on normal cells. Druker collaborated with Novartis chemist Nicholas Lydon, who developed several candidate inhibitors. From these, imatinib was found to have the most promise in laboratory experiments. First Druker and then other groups worldwide demonstrated that when this small molecule is used to treat patients with chronic-phase CML, 90% achieve complete haematological remission. It is hoped that molecular targeting of similar defects in other cancers will have the same effect.