Two key senators are working to build support for a bill aimed at lowering insulin prices and capping monthly copays under commercial and Medicare insurance plans.

The move is the next step in advancing one of Democrats’ most popular provisions from a stalled reconciliation bill ahead of a tough midterm election, although it’s not clear whether it has the votes to pass. In March, the House passed its own standalone version, sponsored by frontline Democrats, to cap insulin copays. 

The Senate bill, released Wednesday by Senate Diabetes Caucus Co-Chairs Jeanne Shaheen, D-N.H., and Susan Collins, R-Maine, aims to entice drugmakers to lower their list prices to 2021 net Medicare rates by blocking pharmacy benefit managers from negotiating drug rebates or other discounts. 

Drug manufacturers and critics allege the discounts, which are often a percentage of the list price, encourage higher prices. The duo’s previous insulin bill aimed to reduce prices to 2006 list prices.  

The bill would also cap monthly copays for those insulin products at the lesser of $35 or 25 percent of the list price per month in commercial and Medicare Part D plans, and limit administrative hurdles that can prevent doctors from prescribing a medication. 

Senate Majority Leader Charles E. Schumer, D-N.Y., immediately endorsed the measure.

“It is my intention to bring the INSULIN Act to the floor of the Senate very soon, and it ought to pass this chamber expeditiously,” he said on the floor.

It’s not yet clear whether Republicans support the measure. Collins recently briefed Minority Leader Mitch McConnell, R-Ky., on the deal, but he has not publicly endorsed the bill. Just 12 Republicans voted to cap insulin copays in the House.

“This is a very complicated issue when you get into the pricing of insulin,” Collins said. “So my goal is to talk to people about the rebate system, about why it keeps prices high and talk to them about our bill.”

 Shaheen said they do not have a final cost estimate for the bill.  The House bill to cap copays was estimated to cost $20.4 billion over a decade, with $9 billion of that attributed to increased money for a Medicare improvement fund. The senators plan to fully offset any projected spending.

The measure effectively merges the duo’s rebate provisions with a separate bill to cap insulin copays from vulnerable Georgia Democratic Sen. Raphael Warnock. Schumer previously pledged to bring Warnock’s bill to the floor before deferring to Shaheen and Collins, whose bill also aims to lower prices for the uninsured.

Patient advocates criticized the bill for not forcing drugmakers to lower their prices. 

“It is difficult to imagine insulin makers will voluntarily reduce their net prices,” said David Mitchell, founder of Patients For Affordable Drugs Now. “History tells us we cannot rely on pharma to do the right thing, and this bill does not offer any enforcement.”

It’s not yet clear how willing the industry would be to adhere to the bill. 

The Pharmaceutical Care Management Association, which represents pharmacy benefit managers, said average cost-sharing for insured patients was $22.88 in 2021 — below the bill’s $35 cap.

“​​The primary impact of this legislation will be to allow drug manufacturers to maximize their profits on insulin products,” the group said.

Drugmakers typically support limits on rebates and copays. Two of the three main insulin manufacturers — Eli Lilly and Sanofi — said they were still reviewing the text. 

“This legislation rightly recognizes the role of insurers and middlemen in determining what people pay at the pharmacy,” Pharmaceutical Research and Manufacturers of America spokesperson Brian Newell said, but he added that more is needed to fix the “broken system.” 

“We believe that lawmakers should keep working on solutions to help all patients with policies like sharing rebates and discounts directly with patients.”