The Federal Trade Commission said Friday that it is suing three drug middlemen, accusing them of inflating insulin prices.

Regulators say the nation's largest pharmacy benefit managers are partly to blame for the soaring cost of insulin in the U.S.

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