Inclisiran is a small interfering RNA that acts as an inhibitor of a proprotein convertase, specifically, inhibiting translation of the protein termed proprotein convertase subtilisin/kexin type 9 (PCSK9). Small interfering RNA molecules (siRNAs) are designed to intervene in the pathway of RNA interference (RNAi), a naturally operating mechanism, wherein they bind to a complex within the cell termed the RNA-induced silencing complex (RISC); after binding, the RISC structure in the siRNA-RISC complex is altered, allowing it to cleave specific messenger RNA molecules (mRNAs). The siRNA-RISC complex is catalytic, and thus can cleave multiple copies of the mRNA that it targets; cleaved mRNAs are not translated into proteins, and thus the concentration of the protein targeted by the siRNA design is decreased.
