Today, the Federal Trade Commission brought action against the three largest prescription drug benefit managers (PBMs)—Caremark Rx, Express Scripts (ESI), and OptumRx—and their affiliated group purchasing organizations (GPOs) for engaging in anticompetitive and unfair rebating practices that have artificially inflated the list price of insulin drugs, impaired patients’ access to lower list price products, and shifted the cost of high insulin list prices to vulnerable patients.