(Reuters Health) - During the first year an expensive class of new cholesterol-lowering drugs was on the market, only one in three patients with a prescription actually received the therapy due to lack of insurance approval and high copays, according to a study sponsored by a manufacturer of one such drug.

The drugs, known as PCSK9 inhibitors, are intended for use by adults whose “bad” low-density lipoprotein (LDL) cholesterol levels remain dangerously high even though they’re taking maximal doses of traditional cholesterol-lowering medications.

Because PCSK9 inhibitors can cost up to $14,000 per year, insurance companies usually require prior authorization and patient copays.

In the new study, the rate of insurance company approval of PCSK9 inhibitors was 47.2 percent. Ultimately, only 34.7 percent of patients prescribed the medicine ever picked it up due to its high out-of-pocket cost.

The higher the copay, the higher the rate of “prescription abandonment,” the study found. When the copay was more than $350, more than 75 percent of patients didn’t pick up the medication.

For the analysis, published in JAMA Cardiology, researchers examined pharmacy claims data on 45,029 patients prescribed PCSK9 inhibitors in the U.S. in 2015 and 2016.

The two PCSK9 inhibitors approved in the U.S. are Praluent (alirocumab) marketed by Sanofi/Regeneron and Repatha (evolocumab) marketed by Amgen, the sponsor of the current study. Overall, this class of injectable drugs has been shown to lower LDL cholesterol levels by up to 60 percent.

Twenty percent of patients in the study received approval from their insurance provider on the first day. Of those whose prescriptions were rejected, 73.5 percent appealed or resubmitted, after which an additional 45.4 percent were approved to receive the medication.

Most of the time, PCSK9 inhibitors get denied the first time around, said lead study author Dr. Ann Marie Navar of the Duke Clinical Research Institute in Durham, North Carolina.

“Personally, every time I prescribe PCSK9 (inhibitors) it takes me three to six hours of work between filling out forms and being on the phone with insurers. On the aggregate the burden of prescribing it is increasing and becoming quite onerous,” Navar told Reuters Health by phone.

Dr. Robert Eckel, professor of medicine at the University of Colorado School of Medicine in Denver and former president of the American Heart Association, told Reuters Health that when he prescribes PCSK9 inhibitors, he often hears back from an insurance company with an approval within half an hour.

“I know the indications of the drug, how to assess its risk and when I need to push hard,” he said. “I often also explain to my patients upfront that I’m the prescribing physician and not in a position to discuss copays.”

Navar noted that cardiologists in the study were more successful than internists or endocrinologists at getting insurance approval, possibly because cardiologists are more likely to pick the right therapy for patients who meet the right criteria for drug approval. Specialty pharmacies that help patients navigate the paperwork process were also more successful.

Weaknesses in the study make it impossible to know whether denial of prescriptions was inappropriate, however.

For example, data on use of statins or LDL level were only available for a small subset of participants. Also, Eckel pointed out, there was no information about why approval was declined for some patients. “This is a very important piece of data that’s related to whether the prescribing physicians followed the approved indications for the drug,” he said.

“I’m not surprised by what the study found, but I’m not sure who’s at fault here,” Eckel said.

Dr. Navar has had financial relationships with both Amgen and Sanofi/Regeneron.

SOURCE: bit.ly/2fRtHpd JAMA Cardiology, online September 27, 2017.