Protein tyrosine kinase inhibitors: new treatment modalities?

Protein tyrosine kinases (PTKs) have been recognized as attractive cell-signaling targets for drug discovery in the treatment of cancer and other diseases. Most of the PTK inhibitors are small molecules, designed to compete for, or nearby, the ATP-binding site, and are currently in phase I-III clinical trials, mainly for oncological indications. Recent efforts focused on the synthesis of selective PTK inhibitors have generated several promising clinical candidates, which recently culminated in the approval of Gleevec(TM), the first kinase inhibitor registered for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors.