The newly approved cholesterol-lowering drug, Praluent, is powerful almost beyond belief. It can drive levels of LDL cholesterol, the dangerous kind, into the 20s or even the teens, numbers almost never before seen in adults. In general, it lowers cholesterol by 50 to 70 percent, compared with 15 to 20 percent with statins.

The $14,600 yearly price of the drug, which is injected under the skin once every two weeks, is a stunner. Yet for some patients, that might actually be a bargain.

Todd DeRuchie’s current cholesterol-lowering regimen costs $8,000 a month, paid by his insurer. The treatment, known as apheresis, is time consuming and onerous, requiring that the construction business owner go to a clinic and sit for hours while his blood flows into a machine that cleanses it of LDL cholesterol. Two weeks later, the LDL is back again, and he has to repeat the process.

The new drug can allow him to avoid all that for a fraction of the price.

“Cost is in the eye of the beholder,” said Daniel Soffer, DeRuchie’s cardiologist at the University of Pennsylvania. Praluent, developed by Sanofi and Regeneron Pharmaceuticals, and other drugs in the pipeline like it, known as PCSK9 inhibitors, are “a game changer,” he added.

Most people with high cholesterol can successfully lower it with statins, which can cost pennies a day. But DeRuchie has a form of heterozygous familial hypercholesterolemia, or FH, an inherited condition that causes extremely high cholesterol, and is much more troublesome. It is a genetic condition that affects an estimated 1 million Americans.

Doctors say FH is more common than cystic fibrosis or Down syndrome, yet largely unrecognized. Only 1 to 10 percent of people with FH know they have it, often because doctors do not think of it when patients have high cholesterol. A genetic test for the condition, which costs $800 to $1,000, is generally not covered by health insurance.

People with heterozygous FH have a twentyfold increased risk of heart disease. Men who are not treated have a 50 percent chance of having a heart attack by age 50. Untreated women have a 30 percent chance of having a heart attack by age 60.

Most cannot reduce their cholesterol to optimum levels even if they take several powerful drugs, said Joshua Knowles, a Stanford University cardiologist and chief medical adviser of the FH Foundation, an advocacy group. Nationwide, about 600 patients are receiving apheresis, although about 15,000 could benefit from it, even under the high bar insurance companies have set for covering it, Knowles said.

The question now for health insurers and heart disease researchers is whether the advent of PCSK9 inhibitors will change this picture. Will doctors become more aware of FH and start making a serious effort to get patients appropriate treatment? Will some doctors stretch the definition of FH so patients who could be treated with statins end up with the expensive drugs? And what will be the cost to the health care system?

The diagnosis of FH is a clinical one, Soffer said. Without the genetic test, doctors diagnose the condition when they see levels of LDL cholesterol above 190 in adults and 160 in children and a family history of early heart disease. It sounds simple, but all too often patients with FH go unnoticed.

“Most in the medical community are not lipidologists,” Soffer said. “They tell these patients they are eating too much french fries and ice cream.”

When DeRuchie, 49, first had his cholesterol measured 20 years ago, he received the stunning news that it was higher than seemed possible. His LDL level was hovering around 250, more than twice what a healthy person might have.

His doctor ordered him to get it down. Heart disease ran in his family. His mother had a heart attack in her 50s and a triple bypass in her 70s. His grandmother and her siblings died from heart disease. A recent CT scan that looks for calcium in coronary arteries, a sign of heart disease, found that DeRuchie’s arteries were loaded with plaque.

DeRuchie, who lives in a Philadelphia suburb and also works in the insurance industry, tried taking statins and other drugs, but said he could not tolerate them. Statins, in particular, made him feel tired, he said, and made his muscles ache. When he arrived at the University of Pennsylvania’s lipid clinic, he was not taking anything to lower his cholesterol.

Soffer suggested apheresis, and DeRuchie agreed to try it. It often leaves him exhausted, but it drives his LDL level down to about 120, at least temporarily.

Another of Soffer’s patients, Marie Damm of Doylestown, Pennsylvania, began taking Praluent as a subject in a clinical trial. When it ended, participants were allowed to continue with the drug, and Damm enthusiastically agreed. But her condition is so severe that even Praluent is not enough.

Damm, 54, had her cholesterol tested when she was a teenager at a free screening at a local mall. It was a spur-of-the-moment action, but the results were stunning. Her total cholesterol level was 435. Her mother’s side of the family tended to have heart attacks, but no one really appreciated the genetic connection, Damm said.

“We just thought we had high cholesterol,” she said.

When Damm started taking Praluent as part of the trial in July 2013, her total cholesterol level was 475, and her LDL was 382. Yet she was taking maximum doses of Zetia, which is a statin, and Welchol, which works in the intestine to lower cholesterol.

Praluent worked; it slashed her LDL to 166. “I was like, ‘Hurray, I’ve never had that level,’” she said.

But 166 is still dangerously high, Soffer said. And a CT scan of her coronary arteries showed they were filled with plaque.

“Marie has run out of pharmacological options,” Soffer said. There are other drugs that might help — lomitapide (costing $250,000 a year) and mipomersen ($176,000) — but her insurer has refused to pay for them.

Now Damm is faced with a choice: Live with that LDL level and continue taking Praluent, or add apheresis. She dreads the thought of apheresis.

Her mother had a heart attack when she was 56, and went on to have stents, bypass surgery, an aortic aneurysm and a kidney lost to atherosclerosis. She died of a stroke July 7.

“I look at all she went through, and I am afraid,” Damm said. “I don’t want to have a heart attack and not make it.”

“If I have to do apheresis, if that’s what it takes, I am going to do it.”

© 2015 The New York Times Company