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try to differentiate itself. Alirocumab and evolocumab are antibodies that bind to PCSK9 in the blood and block its activity. Inclisiran is a drug that uses RNA interference—a method of stopping genes from producing disease-causing proteins—to prevent the liver from making PCSK9 in the first place. The proposed benefit of inclisiran is convenience: Alirocumab and evolocumab have to be administered once or twice a month, while inclisiran could potentially be injected just two or three times a year. A small, shorter Phase 1 study, published earlier this week in the New England Journal of Medicine, showed that average LDL-C reductions for a single 300 mg dose of inclisiran were about 50 percent after four to six months. Though there are many caveats to comparing drugs across trials, inclisiran investigator Ray says inclisiran’s effectiveness is “in the same ballpark” as the approved antibody drugs.
Ray says that reducing the number of injections inclisiran could ultimately make for better control over patients’ cholesterol levels, though. “The more complicated a drug regimen is the less compliant [patients] are over time,” he says. Inclisiran could be like a flu shot. “You go to the doctor, and the nurse gives you the injection and you go away and you’re fine [for] six months.”
Not everyone is convinced that doctors would jump at the chance to switch patients off of antibody drugs for inclisiran, even if its safety and effectiveness hold up in longer, larger studies. Ethan Weiss, a cardiologist and associate professor at UCSF, who isn’t involved with Medicines Co., says that doctors might hesitate given that RNAi is a relatively new drugmaking method with—as of yet—no approved therapies. Antibody drugs are much more established, and Amgen and Regeneron’s drugs will have been on the market for several years if and when inclisiran gets there.
“If you’ve got a once a month dosing regimen are you really that much better off with a once every six months? What are you getting for that?” says Weiss. “As a doctor, and even if I were a patient looking at these therapies to take, I’d ask myself: Is it worth all the unknowns when there’s a readily available alternative therapy that is really well studied?”