Abstract
Kinases have emerged as one of the most intensivelypursued targets in current pharmacological research,especially for cancer, due to their critical roles in cellularsignaling. To date, the US FDA has approved 28 smallmoleculekinase inhibitors, half of which were approvedin the past 3 years. While the clinical data of theseapproved molecules are widely presented and structure–activity relationship (SAR) has been reported forindividual molecules, an updated review that analyzesall approved molecules and summarizes current achievementsand trends in the field has yet to be found. Herewe present all approved small-molecule kinase inhibitorswith an emphasis on binding mechanism and structuralfeatures, summarize current challenges, anddiscuss future directions in this field.