A drug from Alnylam Pharmaceuticals Inc. and Medicines Co. cut bad cholesterol levels among patients in a small trial by about as much as new treatments from Sanofi, Regeneron Pharmaceuticals Inc., and Amgen Inc., with far less frequent dosing.
The experimental drug belongs to a group of treatments that target a protein, PCSK9, that lets too much bad cholesterol circulate in the blood. The results were presented Sunday at the European Society of Cardiology Congress in London.
Cambridge-based Alnylam’s drug, called ALN-PCSsc, blocks PCSK9 from being made by the body, while the current drugs inhibit it after it’s already been produced.
Sanofi and Regeneron’s PCSK9 inhibitor Praluent was approved by US regulators last month, and Amgen got the nod for its treatment, Repatha, last week. Those injections are given every two to four weeks, while ALN-PCSsc could be dosed once every three or possibly even every six months, according to Alnylam’s chief executive, John Maraganore. If eventually approved, ALN-PCSsc could pose a competitive threat.
“We’re seeing a durability that is really stunning,” Maraganore said by phone. “You go to four times a year, twice-a- year injections, it’s almost like having a flu shot for LDL at that point.”
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Because it can be given so infrequently, ALN-PCSsc may address one of the biggest issues in medicine: the fact that patients often stop taking their drugs, or don’t take them regularly. Among people prescribed statins, pills taken daily to fight bad cholesterol, about half stop taking them after a year, according to a 2013 study.
“We need to double down on compliance and get people to do things better, and one of the ways to do that is to lower the frequency of how often they have to do it,” said Kim Williams, president of the American College of Cardiology.
“It’s a novel concept and it’s very encouraging” data, Williams said. “The big concern would be what happens over time and what happens in a larger number of patients. And when we have that, if they are parallel to the data they’ve gotten in a small cohort, it really sounds like a major advance.”
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Patients taking the drug in a randomized trial saw bad cholesterol levels fall as much as 64 percent, on average, compared with about a 20 percent decline for those taking a placebo. ALN-PCSsc showed no serious side effects in the study, which looked at 69 patients with high levels of bad cholesterol.
ALN-PCSsc has longer-lasting results because it uses a different tack to go after PCSK9. While other treatments tamp down the protein after it’s been made, ALN-PCSsc uses an approach, known as RNA interference or RNAi, that stops PCSK9 from being produced in the first place. By silencing select strands of RNA, which are the cell’s messengers that send instructions to manufacture proteins, RNAi works at “turning off the faucet” instead of treatments that “mop up the floor,” as Alnylam puts it.
Medicines Co. will take over development of ALN-PCSsc and plans to start a larger trial by year’s end. Alnylam can receive royalties of as much as 20 percent from sales of the drug.