The patients in the trial were already taking statins and yet their risk was cut further by the new therapy.
A study found patients treated with Repatha were 27 per cent less likely to have a heart attack over two years than if they had been taking statins alone - and 21 per cent less likely to have a stroke.
A new medical technique known as RNA interference therapy is found to be capable of switching off the genes responsible for increasing blood cholesterol levels in the body.
An global trial of 27,000 patients found that those who took the drug evolocumab saw their bad cholesterol levels fall by around 60% on average. All participants were taking inexpensive, cholesterol-lowering statins that were effective in providing an average LDL of 92, which is in range of optimal LDL of under 100.
But that was based on early studies that showed the drug could merely reduce cholesterol and stop furring of arteries.
It is why millions of people take drugs called statins to reduce the amount of bad cholesterol.
The drugs, evolocumab (Repatha) and inclisiran, both work by targeting PCSK9, an enzyme that regulates the liver's ability to remove "bad" LDL cholesterol from the bloodstream.
The new study provides much stronger evidence that it saves lives.
But heart experts aren't convinced the benefits of these drugs justify the cost, at least in most patients.
The study, in the New England Journal of Medicine, tested Repatha on patients in 49 countries, 1,500 in Britain.
Evolocumab was also associated with a 20 percent reduced risk of heart attack, stroke or sudden heart death, said lead researcher Dr. Marc Sabatine, chair of cardiovascular medicine at Brigham and Women's Hospital, in Boston.
"The end result was cholesterol levels came down and down and down, and we've seen cholesterol levels lower than we have ever seen before in the practice of medicine".
However, new drug evolocumab changes the way the liver works to also cut bad cholesterol.
The cost varies, but it is thought to cost the UK's NHS about £2,000 per year per patient where it is already being given to people who do not respond to statins. "It's a little more convenient for patients, potentially".
However, some heart experts question whether the pricey medications, one of which costs roughly $14,000 a year to take, perform well enough to make them worth the extra money.
Professor Naveed Sattar of Glasgow University said: 'These results, I think, will mean the guidelines are adjusted slightly, but unless the price comes down it won't mean we give it to anyone by any means'.
However, Prof Sever said: "They will probably not [replace statins], there are an bad lot of people with really quite high cholesterol out there and we'll probably need more than one drug to get their levels down".
Prof Sir Nilesh Samani, of the British Heart Foundation, said: "Creating new treatments with this approach could prove life-saving for patients with high cholesterol and those who cannot tolerate statins".
In fact, some cardiologists said the drugs should be reserved only for patients with the highest heart risks.