Scientists say the new drug can prevent heart attacks and strokes by cutting bad cholesterol levels.
The patients in the trial were already taking statins, which are used to reduce low-density lipoprotein (LDL) cholesterol.
Despite this, the patients who took evolocumab saw their bad cholesterol levels fall even further.
Patients who took the drug were also less likely to suffer from a heart attack or stroke than those who took the placebo.
The study found that for every 74 people who took the drug for two years, one heart attack or stroke would be prevented.
However, the findings, published in the New England Journal of Medicine, found that the drug had no impact on the rate of cardiovascular mortality.
Professor Peter Sever, from Imperial College London, which led the UK branch of the study, said: "This is one of the most important trials of cholesterol-lowering since the first statin trial, published 20 years ago.
"Our results suggest this new, extremely potent class of drug can cut cholesterol dramatically, which could provide great benefit for a lot of people at risk of heart disease and stroke."
There are approximately 2.3 million people living with coronary heart disease (CHD) in the UK, according to the NHS.
CHD is responsible for more than 73,000 deaths a year in the UK, and occurs when fatty substances build up in the arteries, making it harder for blood to get to the heart.
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