All 500+ human protein kinases share a similarly-shaped active site. Since most kinase inhibitors target this active site, they have the potential to interact with a significant portion of the kinase protein family. While Gleevec is quite selective and well tolerated, most approved kinase-targeted drugs are quite non-selective, or promiscuous. Historically, promiscuity has been a characteristic of the kinase inhibitor class. While targeting more than one kinase benefits certain conditions, the majority of kinases inhibited by these promiscuous drugs have roles that remain unknown. Such inhibitors are generally poorly tolerated and their nonselective inhibition of kinases significantly increases their development risk. Off-target toxicities can outweigh any potential clinical benefit. We believe our approach and competency in kinase drug discovery enables us to create kinase inhibitors that have controlled and well-designed inhibition profiles. As more kinase inhibitors are advanced into clinical development for the treatment of cancers and non life-threatening conditions such as autoimmune and inflammatory disorders, we believe selectivity will become paramount to competitive differentiation.