An updated patent review of small-molecule c-Met kinase inhibitors (2018-present)

INTRODUCTION: c-Met tyrosine kinase receptor is a high-affinity ligand of hepatocyte growth factor (HGF). c-Met is widely expressed in a variety of normal human tissues, but shows abnormally high expression, amplification or mutation in tumour tissues such as lung, gastric and breast cancers. Therefore, the use of c-Met as a target can achieve the inhibition of a series of abnormal physiological processes such as tumourigenesis, development and metastasis. A number of small molecule tyrosine kinase inhibitors targeting c-Met have been successfully marketed. AREAS COVERED: This article reviews recent advances in patented c-Met small molecule inhibitors and their inhibitory activity against various cancer cells from 2018 to date. EXPERT OPINION: To date, small molecule inhibitors targeting c-Met have demonstrated impressive therapeutic efficacy in the clinical setting. Most recent patents have focused on addressing the direction of c-Met amplification and overexpression. Despite the great success in the development of selective c-Met inhibitors, the effects of bypass secretion and mutagenesis have led to a need for new c-Met small molecule inhibitors that are safe, efficient, selective and less toxic with novel structures and effective against other targets.