Dive Brief:

• The struggle of PCSK9 inhibitors to gain traction on the market despite powerful cholesterol-lowering ability has been a well-covered story since the drugs' approval in 2015. A new study published in JAMA Cardiology Wednesday highlights how coverage barriers have meant many prescriptions are never approved.
• ​In the year after approval (August 2015 to July 2016), less than half of the roughly 45,000 patients newly prescribed PCSK9 inhibitors received insurer approval. And only a third of those patients who successfully secured coverage ended up filling their prescription, a data point the study explains as due to high copays. 
• Approval rates varied almost three-fold between the ten largest pharmacy benefit managers, and  differences in copay costs almost entirely accounted for the high abandonment rates seen.

Dive Insight:

PCSK9 inhibitors, developed to lower cholesterol in patients with persistently elevated low-density lipoprotein cholesterol (LDL-C) despite statin therapy and in patients with genetically high cholesterol, are highly effective and well tolerated. In 2015, the Food and Drug Administration approved Amgen's Repatha (evolocumab) and Sanofi and Regeneron's Praluent (alirocumab), but neither have made the expected inroads into the market.

Much of the story since approval of Repatha and Praluent, though, has been around the drugs' high list prices, which top $14,000 a year. In response, payers have put strict prior authorization practices in place and instituted high copays for the drugs. 

These cost and approval barriers, according to the pharmacy transaction data study published in JAMA Cardiology, have been a major factor impeding uptake of the drugs. 

"Although the 'sticker price' for therapy may be the same for all patients, how much patients actually paid out of pocket varied widely, from $0 for the lowest quartile of patients to more than $300 per month for the highest quartile," the researchers wrote. 

While the study specifically did not consider the appropriateness of the drug's cost, it is clear from the data that insurers have put in place strict limits on use. Even for the 47% or so of patients who obtained approval, one in six were only able to do after more than a month of appeals. 

Studies like this will likely be pointed to by both sides in the cost debate. Amgen and the team of Sanofi and Regeneron can argue insurers are broadly limiting use of the drugs, without a more nuanced consideration of which patients are higher risk and more in need of treatment. On the other side, the data hints at the difficulties payers face in budgeting for broader use of a pricey biologic. 

The Institute for Clinical and Economic Review, a closely watched research group, has argued that Amgen's Repatha should be priced at 85% to 88% less than its current list price to be considered cost-effective, taking it down to $1,725 to $2,242 rather than near $14,500.

A study sponsored by Amgen, on the other hand, suggests the drug would be cost-effective at $9,669, which is about the level of the drug's net cost after rebates and discounts.