Checkpoint kinase inhibitors: a patent review (2009 - 2010)

INTRODUCTION: Cells that suffer DNA damage activate the checkpoint kinases CHK1 and CHK2, which signal to initiate repair processes, limit cell-cycle progression and prevent cell replication, until the damaged DNA is repaired. Due to their potential application as novel anticancer therapies, inhibitors of CHK1 and CHK2 have become the focus of numerous drug discovery projects. AREAS COVERED: This patent review examines the chemical structures and biological activities of recently reported CHK1 and CHK2 inhibitors. The chemical abstract and patent databases SciFinder and esp@cenet were used to locate patent applications that were published between September 2008 and December 2010, claiming chemical structures for use as CHK1 or CHK2 inhibitors. EXPERT OPINION: This is an exciting time for checkpoint kinase inhibitors, with several currently in Phase I or II clinical trials. Many of the CHK1 inhibitors contained within this patent review have shown preclinical efficacy in combination with DNA-damaging chemotherapies. CHK1 inhibitors have recently been demonstrated to be efficacious as single agents in preclinical models of tumors with constitutive activation of CHK1 or high intrinsic DNA damage due to replication stress. The level of newly published patent applications covering CHK1 and CHK2 inhibitors remains high and a diverse range of scaffolds has been claimed.