Innovative Science

siRNA: A revolutionary approach for treating the root cause of diseases

Small interfering RNA (siRNA) therapies represent a new approach to harness a natural biologic pathway called RNA interference (RNAi). Through RNAi, our bodies regulate the production of different proteins. Researchers first discovered RNAi in 1998. The 2006 Nobel Prize for Physiology or Medicine, awarded to Craig Mello and Andrew Fire, recognized RNAi as a major scientific discovery and set the stage for new breakthroughs in medicines by targeting the root cause of diseases.

siRNA therapies are widely considered some of the most promising frontiers in drug development today. siRNA acts “upstream” compared with today’s medicines, preventing the production of disease-causing proteins. A simple analogy is that siRNA therapies work by “turning off the faucet” of disease-causing proteins compared with medicines that inactivate disease-causing proteins after they have been produced. siRNA therapies are designed to be highly selective, working precisely at the desired target and minimizing the risk of off-target effects.

Another feature that distinguishes siRNA is the possibility for infrequent dosing, because siRNA acts as a catalyst on messenger RNA (mRNA), and remains active over a prolonged duration of time.


Ribonucleic acid is present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins.

From biology to therapy

In the early 2000s, researchers showed that approximately one out of every 20 people have naturally reduced proprotein convertase subtilisin/kexin type 9 (PCSK9) due to inherited variants in the gene which encodes the PCSK9 protein. As a result, these people have naturally lower levels of LDL-C, which lowers their risk of cardiovascular disease by as much as 88 percent over their lifetime1. These observations spurred the discovery and development of inclisiran as a way to harness natural RNAi processes to achieve sustained reductions in LDL-C over time. Inclisiran is currently being investigated to prevent the production of PCSK9 at its source in the liver.

As part of the ORION development program, ongoing studies are assessing the cholesterol-lowering effects and safety of inclisiran when administered twice yearly. Inclisiran is not yet approved for use by the FDA or any other regulatory authority.

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