The Federal Trade Commission (FTC) on Friday sued the three largest pharmacy benefit managers (PBMs) for engaging in alleged anticompetitive practices that boosted profits while “artificially” inflating the list price of insulin.

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

Cigna Group’s pharmacy benefit manager Express Scripts on Tuesday sued the U.S. Federal Trade Commission, alleging that the agency’s July report on the PBM industry was biased and defamatory and asking the court to order the FTC to withdraw the report.