Insulin, used by millions of Americans, has taken center stage in the high-stakes battle over health care costs. Though prescribed for the past 100 years, only three companies supply insulin in the U.S. and much of that is higher-cost branded versions, despite the increasing availability of lower-price biologic options.

Months earlier, the agency released a report alleging the companies drove up the costs of some medications, including insulin.

The Federal Trade Commission on Friday filed a lawsuit over insulin prices against the three largest pharmaceutical middlemen that negotiate prescription drug prices, arguing that the companies artificially inflate the costs of the lifesaving diabetes drug for patients.

The U.S. Federal Trade Commission sued the country's three largest pharmacy benefit managers on Friday, accusing them of steering diabetes patients towards higher priced insulin in order to reap millions of dollars in rebates from pharmaceutical companies.

The Federal Trade Commission on Friday filed lawsuits against three prescription drug benefit managers or PBMs over concerns the companies are artificially inflating the list price of insulin drugs.

The Federal Trade Commission took action Friday against the three largest pharmacy benefit managers, accusing the companies of “engaging in anticompetitive and unfair rebating practices that have artificially inflated the list price of insulin drugs,

The Federal Trade Commission sued the drug middlemen that health plans use to keep a lid on drug spending, accusing the firms of inflating the price of insulin.

The US Federal Trade Commission sued units of CVS Health Corp., Cigna Group and UnitedHealth Group Inc. on Friday, accusing the drug middlemen of engaging in illegal rebate programs that drove up the price of insulin.