Platelet-derived growth factor receptor tyrosine kinase inhibitors: a review of the recent patent literature.

IMPORTANCE OF THE FIELD: Platelet-derived growth factor receptor (PDGFR) is a compelling target for developing therapeutic agents to treat diseases associated with overactivated platelet-derived growth factor (PDGF) signaling and has proved to be particularly encouraging for cancer treatment. The efforts in this area have been greatly enhanced by the approval of tyrosine kinase inhibitors with PDGFR inhibitory activity such as imatinib, sunitinib and sorafenib. AREAS COVERED IN THIS REVIEW: This review surveys the small molecule PDGFR inhibitors reported in patent literature over the past 5 years (2005 - 2009). WHAT THE READER WILL GAIN: The reader will gain an overview of the chemical scaffolds and the activity/selectivity of the newly discovered PDGFR inhibitors. TAKE HOME MESSAGE: Targeting PDGFR kinase with small molecule inhibitors has remained a very active area. Many new and novel PDGFR inhibitors with different selectivity profiles are being discovered and evaluated. In cancer therapy, the identification of novel and potent PDGFR inhibitors with preferred kinase inhibitory profiles that deliver superior antitumor efficacy, yet have manageable side effects and toxicities, will continue to be the key for success. Additionally, interest in targeting PDGF signaling for intervention of various vascular diseases and fibrotic conditions is expected to continue to grow.