The Federal Trade Commission on Friday sued three large U.S. health companies that negotiate insulin prices, arguing the drug middlemen boost their profits while "artificially" inflating costs for patients.

The agency alleges CVS’s Caremark, Cigna’s Express Scripts and UnitedHealth’s Optum Rx accepted money from drugmakers in exchange for keeping lower-cost insulin off their lists of approved

The complaint, filed by Express Scripts owner Cigna against the FTC and Commissioner Lina Khan, is seeking the retraction of the report, which the company claims is "unfair, biased, erroneous, and defamatory" against the PBM industry and is "seventy-four pages of unsupported innuendo."