BCR and chronic myelogenous leukemia, BCR-ABL1 positive: The discovery that CML is due to the activity of BCR-ABL prompted the design and development Novartis Pharma AG, WKL-136.7.86, Klybeckstrasse 141, CH-4057 Basel, Switzerland of imatinib (Glivec®, GleevecTM, STI571; Novartis Pharma AG), a small molecule kinase inhibitor that targets the PDGFR, c-Kit and Abl kinases (Druker et al, 1996; Buchdunger et al, 2000).