(The Center Square) – A bipartisan group of lawmakers wants to lower prescription drug prices by banning joint ownership of pharmacy benefit managers and pharmacies.

An association representing PBMs warns the proposal could hurt consumers.

Sens. Elizabeth Warren, D-Mass., and Josh Hawley, R-Mo., alongside Reps. Diana Harshbarger, R-Tenn., and Jake Auchincloss, D-Mass., introduced the Patients Before Monopolies (PBM) Act. The bipartisan, bicameral bill would prohibit a parent company of a PBM or an insurer from owning a pharmacy business and require that a parent company divest its pharmacy business within three years, among other changes.

The Pharmaceutical Care Management Association, which represents U.S. pharmacy benefit managers, said the legislation could hurt consumers.

"Congress should be thoughtful in understanding the value that PBMs provide before taking away consumers' ability to access their medicines how and where they'd like, while making the cost of prescription drugs more expensive," the association said in a statement.

Businesses hire pharmacy benefit managers to lower their prescription drug costs, but pharmacy benefit managers have emerged as a target for lawmakers as drug prices increase. Pharmacy benefit managers say they secure savings for patients and plan sponsors on prescription drug costs through rebates, discounts and other price concessions.

A recent Federal Trade Commission investigation found pharmacy benefit managers inflate prescription drug costs. PBMs said the FTC investigation was flawed.

The three largest PBMs are UnitedHealth Group's OptumRx, Cigna's Express Scripts and CVS Health's Caremark.

The FTC findings came after two years of study and calls from some lawmakers to address the issues presented by PBMs. The FTC requested documents from the six biggest PBMs. The top three PBMs processed nearly 80% of the approximately 6.6 billion prescriptions dispensed by U.S. pharmacies in 2023, while the top six PBMs processed more than 90%. Pharmacies affiliated with the three largest PBMs account for nearly 70% of all specialty drug revenue.

"PBMs have manipulated the market to enrich themselves – hiking up drug costs, cheating employers, and driving small pharmacies out of business," Warren said in a statement. "My new bipartisan bill will untangle these conflicts of interest by reining in these middlemen."

The Pharmaceutical Care Management Association said that's not the case.

"The Hawley-Warren proposed legislation would severely limit access to safe and affordable pharmacies that patients value and rely on for prescription drugs," the group said. "The truth is PBM-affiliated pharmacies, including mail-service and specialty pharmacies, have a proven track record of providing convenient, reliable, and affordable options for patients to access prescription drugs."

The association said mail-service pharmacies could save patients, employers, and public health plans $23.5 billion over a decade. It also said specialty pharmacies typically can reduce the cost of extremely expensive specialty drugs by up to 45%.