The company paid a 13 percent rebate rate when CMS says it should have been paying 23 percent.

The Wall Street Journal:
Lawmakers Accuse Mylan Of Overcharging Government For EpiPen
The federal government says that Mylan NV has overcharged the federal-state Medicaid program by millions of dollars over five years for its emergency auto-injector product called the EpiPen. In a letter Wednesday, Acting Administrator Andy Slavitt of the federal Centers for Medicare and Medicaid Services (CMS), said Mylan wrongly classified the emergency epinephrine product as a generic, when it should have been classified as a brand-name product. In doing so, Mr. Slavitt wrote, Mylan paid a smaller rebate of 13%, or about $163 million, when it should have been paying a rebate of 23.1% or more. (Burton, 10/5)

Mylan Overcharged Medicaid For EpiPen For Years, Despite Warnings
Mylan Pharmaceuticals overcharged Medicaid for its EpiPen device for years, even though the company had been told it …
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CMS: Mylan Overcharged Medicaid By Millions Despite Warnings From Feds