Examining the Value of Pharmacy Benefit Managers

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Most Americans don’t realize there are silent brokers helping to fix the price of their prescription drugs — or that it’s a $100 billion annual business accounting for half of Big Pharma sales.

They’re called pharmacy benefit managers (PBMs), with CVS Caremark, Express Scripts and Optum RX dominating the market. Their chief function is to develop and maintain a list called the “formulary,” a list of drugs that will be covered by health-care plans. The formulary groups drugs into tiers with different levels of patient cost sharing.

They also pool volume across health plans to negotiate with drug manufacturers and retailers on prescription drug pricing. And PBMs reap rewards from rebates and fees that drug manufacturers pay them, as well as from a ‘pharmacy spread’ where PBMs bill health plans more than they reimburse pharmacies.  

All of this comes at a cost to patients.

“Patients typically only think about what they pay out-of-pocket at the pharmacy counter,” said Alex Chan, a PhD candidate in health economics at Stanford Health Policy. He and Kevin Schulman, a professor of medicine and professor of economics, by courtesy, at the Stanford Graduate School of Business, have just published a paper in JAMA Health Forum that examines these silent and powerful intermediaries.

“As PBMs leverage the formulary design to secure more and more rebates and fees from manufacturers, these drug manufacturers raise the list price in response,” Chan said. “The patients’ out-of-pocket cost at the counter would increase but at a less noticeable rate given that they co-pay are just a percentage of the list prices.”

Unless these rebates are passed along to consumers as reduced premiums, the net effect is an increase in premiums. Furthermore, if formulary design is used to help PBMs secure better rebates, PBMs may prioritize expensive drugs over more cost-effective drugs.


These pharmacy benefit managers have come under scrutiny as health policy experts learn more about the scale of prescription drug rebates and other questionable practices used by these intermediaries in the prescription drug market. For example, PBMs can include “gag clauses” that prohibits pharmacists from telling customers about cheaper drug options.

They ask themselves: What is the underlying value of PBMs for both payers and patients?

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Chan and his co-author Kevin Schulman acknowledge that PBMs play an important role in many transactions of the U.S. economy.

“They create value by providing information on the quality and value of products and services and by providing negotiation leverage as they amass scale by aggregating smaller buyers (or sellers),” they write. “Consumers can be sure to share in this value under three conditions: when there is competition among intermediaries, when pricing is transparent, and when it is clearly defined who is negotiating on whose behalf.”

But when these conditions are not met, they add: “We can find that intermediaries can hold a powerful and self-serving position in a market.”

Chan and Schulman found that in the drug prescription market, there are significant concerns about the value of these PBMs:

  1. Rather than a market where there is competition among PBMs, consolidation has resulted in a situation in which the three largest PBMs have about 80% of market share. There are significant barriers to competition among PBMs. If a health system wants to switch PBMs, it requires a significant investment in a “request-for-proposal” process.
  2. Drug-specific rebates are kept confidential between PBMs and drug manufacturers, and health plans have little ability to clearly assess the cost-savings for their members or to gauge the appropriateness of the rebate passthroughs.
  3. Under the rebate model, the role of the PBM has evolved to serving as an agent of both the payer and the manufacturer. The interests of payers and manufacturers are often in conflict, especially with respect to expenditures.

"One of the largest criticisms of PBMs is the lack of transparency surrounding the structure and scale of payments from manufacturers to the PBM,” the authors write. “The current PBM business is shrouded in secrecy.”

Only the PBM knows the actual scope of payments from drug manufacturers, such as rebates and service fees. They note that in 2016, for 13 pharmaceutical companies, payments to PBMs and other intermediaries (such as wholesalers) were $100 billion — or 50% of gross sales.

 “Without transparency, a PBM might develop formularies that maximize payments to the PBM rather than maximize value to patients,” Chan and Schulman write.

Suspicion over just that led health insurance company Anthem to sue Express Scripts for $15 billion in 2016 for overpayments on drug pricing. In the end, Anthem cut ties with Express Scripts to develop its own PBM.

“The PBMs have grown out of sync with what we can reasonably expect to be a value-adding intermediary,” Chan said. “It is hard to really tell how much inefficiencies have been created due to this lack of transparency.”

Legal Solutions

The authors note that Congress has taken steps to shed light on PBMs through the Patient Right to Know Drug Prices Act and the Know the Lowest Price Act, both adopted in 2018. These laws outlaw PBMs gag clauses that forbid pharmacists from telling consumers that their price through a PBM was higher than the as price for the same product.

Chan said these laws are a move toward the direction of providing patients with more transparency about their options.

“An even more promising direction would be for legislation to make a stronger push towards public disclosure of rebates, discounts, and price concessions, along with lower barriers to entry to the PBM market,” he said.