PORTSMOUTH, N.H. — A group of senators has a plan to reduce insulin prices with legislation intended to hold pharmaceutical companies and insurance companies more accountable.

The proposal’s called the Insulin Price Reduction Act and its sponsors say it would incentivize reductions in list prices.

The senators say the plan would create a new pricing model that would benefit both Medicare and private insurance users.

The senators include Republican Sens. Susan Collins of Maine and Kevin Cramer of North Dakota as well as Democratic Sens. Jeanne Shaheen of New Hampshire and Tom Carper of Delaware.

The senators say enrollee out-of-pocket costs for insulin have more than quadrupled since 2007 for Medicare users. Shaheen told a news conference Friday that the price of a month’s supply of insulin can be as high as a new car payment.