Last week's eight-compound deal between Novartis Pharma AG and Vertex Pharmaceuticals Inc. illustrates the building competition in the kinase field, as a growing number of biotech and pharmaceutical companies are pursuing the development of broad libraries of compounds that inhibit protein kinase targets. While a few small molecule kinase inhibitors are in clinical testing, the number of compounds and specific kinase targets is likely to increase dramatically.

Kinases have become popular targets based on their involvement in most cellular functions and hence most diseases. Kinases are cellular signaling enzymes that catalyze the addition of a phosphorus group onto another protein (phosphorylation), usually to regulate the activity of the substrate protein. The kinase superfamily includes both receptors and cytoplasmic proteins that phosphorylate either tyrosine residues or serine/threonine residues on their targets. First identified as oncogenes activated by retroviruses, the kinase superfamily is now estimated to contain more than 1,000 members involved in a diverse array of signal transduction pathways.