PCSK9 and heart disorder: Given the mode of action of PCSK9 that acts primarily as a circulating inhibitor of the LDLR (6), as well as the healthy profile of individuals with reduced or absent PCSK9 function (7, 8) PCSK9 rapidly gained the status of a very promising drug target to lower LDL-C in humans with the ultimate goal of lowering the risk of heart disease.