Scientists at Alnylam Pharmaceuticals have found that a single dose of a new drug using RNAi lowers cholesterol up to 60 percent in rodents and monkeys.

The drug might one day provide another option for patients who are resistant to existing cholesterol-lowering drugs due to genetic factors, or it might also be used in combination with existing cholesterol-lowering drugs to increase their effectiveness.

Alnylam’s new drug blocks an enzyme called PCSK9, previously shown to affect LDL cholesterol levels and risk of heart disease.

The drug employs an approach known as RNA interference. With this technique, scientists create short RNA molecules that bind to messenger RNA in the cell, causing it to self-destruct. That interrupts the process of gene transcription, and thus the synthesis of the proteins coded by the gene.