A new drug in early development cuts cholesterol as much as two potent injections recently cleared for sale but lasts much longer, meaning it may need to be given only every three to six months, initial findings suggest.
Results with Alnylam Pharmaceuticals and Medicines Co's experimental product ALN-PCSsc highlight the competition for a market tipped to generate billions of dollars in sales.
Unlike rival antibody-based PCSK9 medicines that work in the blood, the new under-the-skin injection is a first-in-class treatment that stops synthesis of the protein which is linked to "bad" LDL cholesterol in the liver.
Targeting PCSK9 is a hot area for drug companies seeking to cut heart risks for millions of people who don't benefit from conventional statin drugs.
Amgen's Repatha and a rival product, Praluent, from Sanofi and Regeneron Pharmaceuticals, are each expected to generate more than $2 billion a year in sales by 2020, according to Thomson Reuters data.
Pfizer also has a PCSK9 drug in late-stage trials, and is experimenting with an oral pill.
Alnylam and Medicines Co's product will be relatively late to the party, as it is unlikely to go on sale before 2020 even if subsequent late-stage studies are successful, but its reduced injection frequency could make it an attractive option.
Results from 69 patients in a Phase I trial, reported at the European Society of Cardiology (ESC) congress on Sunday, found a single dose of 300 mg reduced LDL by just over 50 percent at 12 weeks, similar to the 50-60 percent seen with antibody drugs, and the reduction was still 44 percent after 140 days.
"We're not quite sure exactly how long this stuff lasts but we know it is more than 140 days for many patients," Medicines Co Chief Executive Clive Meanwell told Reuters.
"The ability to control LDL cholesterol with an injection every three to six months will mean patients can get their cholesterol checked while doctors decide if they need another shot, which should improve adherence."
ALN-PCSsc was generally well tolerated with no significant adverse events, though bigger safety and efficacy studies are needed. Medicines Co plans to start a Phase II study by end-2015 and a final-stage Phase III trial by end-2017.
The new drug uses a novel approach known as RNA interference, or gene silencing, to stop the synthesis of PCSK9, giving it the ability to knock down the protein with an injection administered once-quarterly or possibly bi-annually.
"It is a follower, but really it's more of a next-generation idea," said Meanwell.
Cost is a major issue for PCSK9 drugs, with Repatha and Praluent priced at more than $14,000 a year, before discounts. Meanwell said the new drug would probably be cheaper to make but its price would be determined by the value it offered.
Jefferies analysts currently model peak ALN-PCSsc sales of $980 million, after applying a 50 percent risk discount because the drug is still at an early stage.
Shares in Medicines Co and Alnylam rose 6 and 4 percent respectively on Friday ahead of the ESC meeting.