(Reuters Health) - Newer injected cholesterol medicines known as PCSK9 inhibitors can cost Medicare patients more than $300 a month, compared with only about $4 for older statin pills to lower cholesterol, a U.S. study suggests.

Nationwide, approximately 9 million adults with heart disease and hardening of the arteries or a family history of dangerously high cholesterol don’t succeed at lowering their cholesterol to healthy levels by taking statins, researchers note in JAMA Cardiology.

Some patients whose cholesterol is too high with statins or who can’t take the pills because of side effects may benefit from taking a PCSK9 inhibitor in addition to statins or as an alternative, said lead study author Dr. Dhruv Kazi of the University of California, San Francisco School of Medicine and Zuckerberg San Francisco General Hospital.

“Most patients with high cholesterol should continue to receive statins, not just because they are inexpensive but also because we have decades worth of safety and effectiveness data showing that, among high-risk patients, statins save lives,” Kazi said by email.

Both statins and PCSK9 inhibitors are designed to reduce levels of low-density lipoprotein (LDL), the “bad” kind of cholesterol that can build up in blood vessels and lead to clots and heart attacks.

Daily statin pills work by blocking an enzyme the liver uses to make cholesterol, reducing the amount of cholesterol produced. Side effects can include muscle pain and liver damage.

PCSK9 inhibitors work by limiting the amount of cholesterol that enters the bloodstream, and patients typically need to inject these medicines twice a month.

For the study, researchers examined data from June 2016 on drug benefits for Medicare patients to calculate average out-of-pocket costs across all plans available. They focused on two PCSK9 inhibitors, alirocumab (Praluent) and evolocumab (Repatha), as well as the statin atorvastatin (Lipitor), which is available as a generic.

At the time of the study, 88 percent of the plans covered at least one of the two PCSK9 inhibitors.

Patients’ average monthly-out-of-pocket costs were $336 for alirocumab and $321 for evolocumab, the study found.

People who took a statin plus alirocumab had average total annual drug costs of $14,330 including out-of-pocket costs for patients of $4,997. With evolocumab, average total annual costs were $13,760 including $4,968 in out-of-pocket costs for patients.

One limitation of the study is that researchers only looked at patients’ share of costs based on prescriptions for statins and PCSK9 inhibitors, the authors note. In reality, out-of-pocket costs would also be influenced by other medications patients used.

Some previous research suggests that PCSK9 inhibitors might reduce cholesterol 60 percent more than statins alone, said Stacie Dusetzina, a pharmacy and health policy researcher at the University of North Carolina at Chapel Hill’s Eshelman School of Pharmacy, who wasn’t involved in the study.

Recent trials also suggest that some people who don’t achieve low enough cholesterol on statins alone may have a lower risk of heart attack and stroke if they add a PCSK9 inhibitor to their drug regimen, Dusetzina said by email. The odds of dying, however, don’t appear different based on whether or not people take the PCSK9 inhibitor, she said.

“PCSK9 inhibitors are expensive and could potentially be used by a lot of people, so it is important to consider who might really benefit from therapy and to target those patients appropriately,” Dusetzina said. “Studies of the cost effectiveness of these drugs suggest that the price for therapy would need to be dramatically reduced in order to make them a good value.”

SOURCE: bit.ly/2f0eFt7 JAMA Cardiology, online September 13, 2017.