PCSK9 and familial hypercholesterolemia: In addition to statins, a new class of drugs called proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors has been approved by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) in 2015 for the treatment of primary hyperlipidemia and familial hypercholesterolemia (HeFH).