Washington: A new cholesterol-lowering drug evolocumab helps high-risk patients reduce the likelihood of a heart attack or stroke, but its high cost raises questions about how many patients will benefit, researchers said on Friday.
The results of a two-year clinical trial on the drug sold as Repatha by Amgen Phamaceuticals that costs more than $14,000 a year were released at the American College of Cardiology annual conference in the US capital.
The randomised trial involved 27,564 people who had experienced a prior heart attack or stroke, or who had significantly clogged arteries that limited blood flow to their limbs.
Evolocumab reduced low-density lipoprotein (LDL), or 'bad' cholesterol, by 59 per cent.
It also decreased the risk of heart attack or stroke or cardiovascular death by 15 per cent in the first year and 25 per cent in the second year.
"The drug was safe and well-tolerated," said lead study author Marc Sabatine, chair of cardiovascular medicine at Brigham and Women's Hospital in Boston.
Experts not involved in the study described it as 'exciting' and 'major', but urged caution due to the high cost of the medication.
"This is very expensive stuff," said Valentin Fuster, physician-in-chief at Mt Sinai Medical Hospital in New York.
Fuster also noted that in absolute numbers, the drug saved about two per cent of lives.
"We have to be very cautious in terms of the enthusiasm," he told reporters at the conference.
Roxana Mehran, professor of medicine at Mount Sinai School of Medicine in New York, described the findings as 'probably the most important trial here' at the ACC meeting, which is the largest annual gathering of cardiologists in the United States.
"Certainly America cannot afford to be giving this to every patient," she added.
"While we don't want to ration great care, we do need to figure out how to pay for this."
Evolocumab is part of a new class of drugs called PCSK9 inhibitors, which are monoclonal antibodies that help lower cholesterol.
Some patients who are unable to take traditional cholesterol-lowering drugs known as statins, due to their side effects, may be able to take PCSK9 inhibitors instead.
Patients report few side effects from Repatha, which acts differently than statins and does not cause the muscle pain and weakness that some statin users experience.
Repatha gained US Food and Drug Administration approval in 2015.
But its price, and the lack of data on its effectiveness until now, have limited its use.
"The biggest challenge is getting it covered by insurance," Suzanne Steinbaum, director of women's heart health at Lenox Hill Hospital in New York, said.
"When we see a trial like this, I think that the use is going to up exponentially," she added, describing the study - the largest and most extensive of its kind to date when it comes to Repatha - as 'pretty exciting'.
"As demand and use goes up, the insurance companies usually follow," Steinbaum said.
Heart disease and stroke are the number one killers worldwide, taking 15 million lives in 2015, according to the World Health Organisation.
In the United States, heart disease accounts for one in every four deaths, and kills more than 600,000 people every year.
Stubbornly high cholesterol is a key risk factor.
The study showed evolocumab reduced LDL cholesterol by 59 per cent, from a median of 92 to 30 mg/dL.
This made 'a dramatic difference', even if the drug could save just two per cent of patients' lives, said Kevin Marzo, chief of the division of cardiology at Winthrop-University Hospital in Mineola, New York, who was not involved in the study.
"In a disease that affects hundreds of thousands, that is a big difference, preventing a lot of heart attacks, a lot of urgent hospitalisations," he said.
Financial analysts were more critical of the drug's high cost, and Amgen shares fell 6.6 per cent by midday, following the release of the study.
"At a cost of $7,000 a year, this translates to $958,000 per event saved," Bernstein analyst Ronny Gal wrote in a note published by CNBC.
"Thus, in our view, payers will continue to restrict access to the drug."
The study showed the drug prevents only one cardiovascular event per 137 treated patients, he said.