A new study suggests major pharmacy benefit managers may be focusing on specific payer segments in a bid to maintain strong market share.
The analysis, released in the Journal of the American Medical Association, finds that CVS Health's Caremark holds the largest market share overall in the PBM space. However, it led by the largest margin Medicaid managed care, controlling 39.2% of the market.
By comparison, the other members of the industry's "big three"—Cigna's Express Scripts and UnitedHealth Group's Optum Rx—controlled 12.3% and 15.8% of the Medicaid market, respectively.
Dima Qato, Ph.D., director of the program on medicines and public health at the University of Southern California's Leonard D. Schaeffer Institute and the study's corresponding author, told Fierce Healthcare that this level of concentration among an individual PBM raises concerns about network access.
"Medicaid beneficiaries may have CVS pharmacies designated as a preferred pharmacy, even though there may be other chains or independents closer to them," Qato said. "And that could contribute to closures and increase costs if patients decide, unknowingly, to visit their nearest pharmacy, even though it's not preferred."
She added that given the potential to increase costs, this trend also could impact medication adherence for patients who aren't able to readily access the preferred pharmacies for their PBM.
Express Scripts, meanwhile, had its largest share in the commercial market, accounting for 28%. That's on par with CVS (28.5%) and ahead of Optum (16.4%).
The largest chunk of Optum's business was in Medicare Part D, where it controlled 27.7% of the market. CVS holds 33.4% of the Medicare market, and Express Scripts controls 15.4%.
All told, the study found that CVS held a market share of 31.3%, Express Scripts held 22.1% and Optum Rx controlled 20.2%. The PBM sector broadly earned a high score for market concentration based on the Herfindahl-Hirschman Index (HHI), according to the report.
The study dived into data from IQVIA’s National Prescription Audit PayerTrak, including 14 billion prescriptions filled across 91 pharmacy benefit managers in 2023. It also analyzed HHI concentration data from around the country.
The report is the second this week to examine market concentration in the PBM space, which has been a central criticism of the industry from policymakers and regulators. The American Medical Association found that the four largest PBMs, which comprise the big three as well as Prime Therapeutics, control more than 70% of the market.
In July, the Federal Trade Commission released a report that warns the level of concentration among PBMs, as well as vertical consolidation with insurers, "warrants further scrutiny and potential regulation."
Qato said it's critical to track data like this as policymakers weigh next steps because it paints a clearer picture of how the concentration among PBMs may be effecting patients locally.
"Whether it's federal or state policymakers, there really has to be more transparency around how PBMs are able to control so much and yet not be accountable to it in terms of how it impacts access to medications and disparities," she said.