Insulin prices have soared in the past decade due to a “broken” drug pricing system, according to a recent report from the offices of Sens. Chuck Grassley (R-Iowa) and Ron Wyden (D-Ore.). The wholesale acquisition cost (WAC) prices of long- and short-acting insulins have increased aggressively without “significant advances in the efficacy of the drugs,” observed the report, which summarized the findings of a two-year investigation led by the U.S. Senate Finance Committee. Meanwhile, annual pre-rebate spending on insulin products for the Medicare Part D program grew by billions of dollars between 2010 and 2018. The report found that insulin manufacturers raised their WAC prices so that PBMs can get larger rebates, which are based on a percentage of the list prices. In return, the PBMs offer those drugs favorable placement on their formularies.