New RNA-Based Drug Class Tested Successfully in Monkeys
ApoB-targeted therapy cuts cholesterol by 62 percent, low-density lipoprotein by 82 percent
TUESDAY, May 9 (HealthDay News) -- Researchers have used RNA interference, or RNAi, to limit liver production of apolipoprotein B in monkeys, reducing their cholesterol and low-density lipoprotein levels and marking a significant advance towards a new class of drugs, according to a report in the May 4 issue of Nature.
For years, RNAi has been used to effectively silence gene expression in cultured cells and recent work has shown the technology works in mice. Now, Tracy S. Zimmermann from Alnylam Pharmaceuticals in Cambridge, Mass., and colleagues in Canada and Germany extend its usefulness to systemic delivery in cynomolgus monkeys.
A single intravenous dose of up to 2.5 mg per kg of stable nucleic acid lipid particles reduced the expression of APOB messenger RNA and protein in the liver by greater than 90 percent within 48 hours, an effect that lasted up to 11 days. The treatment achieved a maximal cholesterol reduction of 62 percent and a maximal low-density lipoprotein reduction of 82 percent, with no effect on non-ApoB containing high-density lipoprotein.
A significant advantage of RNAi is that it can be used for non-druggable targets, like APOB. "A single, low dose of APOB-specific siRNA resulted in rapid and lasting RNAi-mediated gene silencing, with associated and profound phenotypic changes," the authors write. "Our findings show clinically relevant RNAi-mediated gene silencing in non-human primates, supporting RNAi therapeutics as a potential new class of drugs."