By Dennis Thompson
FRIDAY, March 17, 2017 (HealthDay News) -- Two different injectable drugs can lower cholesterol levels even further than statins do, potentially warding off future heart attacks or strokes, new research suggests.
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.
In fact, some cardiologists said the drugs should be reserved only for patients with the highest heart risks.
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. By blocking the enzyme, the medications spur the body to screen out more cholesterol.
Clinical trial results showed that evolocumab was linked to a 15 percent reduction in the risk of major heart events in patients who are already taking statins due to heart disease. These events include sudden heart death, heart attack, stroke, hospitalization for angina, or surgery to reopen a blocked artery.
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.
"In patients with heart and blood vessel disease who are already on a statin, we know now that adding evolocumab reduces the risk of future heart attack or stroke, and it does it safely," Sabatine said.
Unfortunately, evolocumab did not reduce a person's overall risk of death, or their risk of dying from heart disease, noted Dr. Gregg Stone, director of cardiovascular research and education at NewYork-Presbyterian/Columbia University Medical Center.
"The disappointing thing to me was there was absolutely no difference in mortality," Stone said.
Sabatine said that evolocumab, which costs about $14,000 a year, has been on the market for about two years now. It works by using artificial antibodies to block the receptors for PCSK9 in the liver.
By comparison, inclisiran is a next-generation PCSK9 inhibitor that works by reducing the ability of the liver to produce the enzyme, explained lead researcher Dr. Kausik Ray, a cardiologist at Imperial College London, in the United Kingdom.
Inclisiran can reduce cholesterol by an additional 30 percent to 50 percent on top of statins, Ray's team found.
In addition, inclisiran appears to maintain its effectiveness longer, meaning that patients wouldn't have to come to the doctor as often for cholesterol-blocking shots, said Dr. James Underberg, an internist with NYU Langone Medical Center in New York City.
The inclisiran dosage that produced the best results would require a person to get an initial shot followed by a booster three months later, Ray said. They then could wait up to six months before needing another shot.
By comparison, Underberg said, people must receive an injection of evolocumab either monthly or every other week.
"It's three or four injections a year versus what we're currently doing now, which is 24 or 12 injections a year," Underberg said. "It's a little more convenient for patients, potentially."
The safety data showed no serious ill effects from either drug, which may have even fewer side effects than statins, researchers reported.
But heart experts aren't convinced the benefits of these drugs justify the cost, at least in most patients.
Leading cardiologist Dr. Donald Lloyd-Jones, told the Associated Press that the results are modest and "not quite what we hoped or expected." He is chief of preventive medicine at Northwestern University and an American Heart Association spokesman.
"We should still probably reserve these for the highest-risk patients where statins are not doing a good enough job, at least at the price they are currently offered," said Lloyd-Jones.
Underberg and Stone noted that evolocumab decreases the absolute risk of a heart attack or stroke by about 1.3 percent at two years, and 2 percent at three years.
That means about 74 high-risk patients would have to be treated for two years to prevent one heart attack or stroke or death from heart disease, and that at three years 50 would have to be treated.
At that rate, after five years, just 17 high-risk patients would have to be treated, the authors said.
"In general, the drugs will probably be reserved for patients at high risk who will have a bigger treatment effect," Stone said.
The two clinical trials were funded by the drugs' respective makers -- Amgen for evolocumab and the Medicines Company/Alnylam Pharmaceuticals for inclisiran.
Both trials were reported March 17 in the New England Journal of Medicine, to coincide with planned presentations at the American College of Cardiology annual meeting, in Washington, D.C.