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Drugmaker Eli Lilly and Co announced plans on Monday to sell a half-price version of its popular insulin injection Humalog, as it fends off criticism about rising drug prices in the United States.

Major drugmakers including Lilly, a leading producer of insulin, have come under fire from patients and lawmakers over the rising cost of the life-saving medication used to treat diabetes.

Lilly's rebranded product would be called Insulin Lispro, it said, while Humalog, which makes $3 billion in annual sales, will remain available for those wishing to access it through existing insurance plans.

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Other companies, including Gilead Sciences, Regeneron Pharmaceuticals and Sanofi, have also announced some price cuts in recent years, as the U.S. government increases scrutiny of the industry and high drug prices remains a major voter concern.

The cost of insulin for treating type 1 diabetes in the United States has nearly doubled over a five-year period, leading some patients to put their own health at risk by rationing the medication because they could not afford out-of-pocket expenses.

The list price for Insulin Lispro, to be sold only in the United States, would be $137.35 per vial, Lilly said, adding that could make insulin more affordable for uninsured patients or those with high-deductible insurance plans.

"Today's announcement indicates that Lilly has calculated that the resultant impact of the introduction is at worst, economically neutral with the potential for material political gain," Citi analyst Andrew Baum said.

The Indianapolis-based drugmaker said it had spoken to various "stakeholders" about the price of insulin, including diabetes patients, doctors, advocacy groups, wholesalers and lawmakers.

"For people with diabetes, a lower-priced insulin can serve as a bridge that addresses gaps in the system until a more sustainable model is achieved," Lilly Chief Executive Officer David Ricks said in a statement.

Two U.S. senators last month launched an investigation into rising insulin prices, writing to Lilly and two other leading manufacturers, asking them why the cost of the nearly 100-year-old medication had rapidly risen.

The price of Lilly's Humalog, for instance, rose from $35 to $234 per dose between 2001 and 2015, a 585 percent increase, the senators, Republican Chuck Grassley and Democrat Ron Wyden, had said. The senators did not immediately respond to requests seeking comment on Lilly's announcement.

Lilly has in the past called insulin a highly-rebated product. Drugmakers often argue they have to keep prices high because of rebates or after market-discounts they must pay to pharmacy benefit managers and health insurers to get products on their lists of covered drugs.

The U.S. government in January proposed a rule to end the industry-wide system of rebates, a change that Lilly says it would welcome.