An experimental cholesterol-lowering drug has roughly halved the number of heart attacks and strokes in a clinical trial, researchers reported yesterday.
The results are not conclusive but provide the first evidence that targeting the protein known as PCSK9 could slash cardiovascular disease risk for millions of people.
The injectable drug, alirocumab, developed by Sanofi and Regeneron Pharmaceuticals, is from a new class of medicines also being developed by Amgen and Pfizer. They lower "bad" LDL cholesterol in a new way.
The finding is likely to spur enthusiasm about the drug, which could reach the market next year, although experts said the recent results must be confirmed in a much larger trial.
Sanofi and Regeneron said in July that nine big studies showed consistent LDL reductions with alirocumab, but details from four of these trials have only now been unveiled at the European Society of Cardiology annual meeting in Barcelona.
The encouraging cardiovascular data come from an interim safety analysis of one of these studies showing that patients on alirocumab were less prone to a combination of cardiovascular events, including cardiac death, heart attack, stroke and chest pain requiring hospitalisation.
Patrick O'Gara president of the American College of Cardiology, said the finding was "biologically plausible" but urged caution.
"It's so much wished-for that we must be careful," he said.
All four trials presented in Barcelona showed alirocumab cut LDL by about 55% after 24 weeks.
Side effects included a stuffy nose and upper respiratory tract infections.
Doctors and regulatory authorities are watching closely to see if cutting LDL so sharply will have adverse effects on other areas of the body, notably the brain. So far, there has been no sign of this.
PCSK9 drugs will be targeted first at people with a rare familial condition that raises their cholesterol dangerously, statin-intolerant patients and those at high risk of a heart attack who struggle to control LDL with current medication.
How generally the drugs, in pre-filled syringes or auto-injector pens, will be used will depend on their cost-effectiveness.
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