After years of watching steady increases in prescription drug prices, the Federal Trade Commission says it’s launching an investigation into the role of pharmacy benefit managers, the middlemen that critics say are a key reason Americans spend more for meds than anyone else.

In theory, pharmacy benefit managers, or PBMs, negotiate on behalf on insurers and large employers to keep the pharmaceutical industry from gouging patients.

In reality, they add an extra, costly, layer to the U.S. healthcare system and cut themselves in for a piece of the action, often resulting in higher drug prices.

Insulin is a good case in point.

Researchers at USC found that drugmakers’ share of revenue from insulin sales has declined in recent years, with more of the take from sales going to PBMs, drugstores, wholesalers and insurers.

In 2014, the researchers determined, 30% of insulin revenue went to middlemen. By 2018, those same middlemen were receiving 53% of insulin expenditures — more than half.

“The middlemen, and particularly pharmacy benefit managers, have been effective in negotiating lower prices from manufacturers,” Karen Van Nuys, one of the lead researchers of the study, told me for a column in the Los Angeles Times.

“What they haven’t been doing is sharing gains from those lower prices with patients,” she said. “They’ve been keeping them.”

The three biggest PBMs are CVS Caremark, Express Scripts and Optum Rx. They control nearly 80% of the prescription drug market.

The FTC says it will call on the PBMs to provide records of their operations.

“Although many people have never heard of pharmacy benefit managers, these powerful middlemen have enormous influence over the U.S. prescription drug system,” the FTC’s chair, Lina M. Khan, said in a statement. 

“This study will shine a light on these companies’ practices and their impact on pharmacies, payers, doctors and patients.”

The U.S. healthcare system is very complex and PBMs are just one part of the equation.

But greater transparency about their impact on drug prices is long overdue — as is a discussion about whether they serve industry interests more than those of patients.