The Federal Trade Commission said pharmacy benefit managers created a "perverse drug rebate system" that artificially inflated the cost of insulin.

Three companies that process about 80% of prescriptions in the United States — Caremark, Express Scripts and OptumRx — have engaged in anticompetitive practices that spur price increases, the

The Federal Trade Commission said on Friday that it had taken legal action against the three largest pharmacy benefit managers, accusing the drug middlemen of inflating insulin prices and steering patients toward higher-cost insulin products to increase their profits.