slightly elevated LDL cholesterol (greater than 116 grams/deciliter of blood) to get either one of five different doses or a placebo. The higher the doses went, the better the drug appeared to be at reducing PCSK9 in the bloodstream, as well as LDL. PCSK9 is thought by scientists to be a key to lowering cholesterol, because it makes a protein that interferes with the liver’s ability to get rid of excess cholesterol. Scientists have become increasingly convinced after finding certain individuals with mutant forms of PCSK9 who have extremely low cholesterol.
The study didn’t follow up with patients for an extended period of time, but the anti-PCSK9 effect appeared to be durable enough for Alnylam to consider once-monthly injections for future studies. Importantly to Alnylam, this study used its second-generation lipid-nanoparticle delivery technology, which it intends to use widely in its pipeline of experimental drugs, and which is supposed to be far more potent than other technologies it has used in previous clinical trials.
Lots of questions will surely pop up based on the intriguing early finding. What will be the ideal dose of such an RNAi drug? How does the data compare with cheap generic statins, or anti-PCSK9 antibody drugs in development? How long does the RNAi treatment really last? Does the quick lowering of PCSK9 really translate into extra benefit in lowering of heart attack risk? And how widely might such a drug be used—would it be for large numbers of patients, or only those with extremely high cholesterol that doesn’t respond to statin therapy?
I expect to gather more material on this finding today and will update if necessary.
