US SB1186

Extends Medicare prescription drug inflation rebates to drugs sold in the commercial market, requiring manufacturers to pay rebates when drug prices rise faster than inflation for both Medicare Part B and Part D drugs

Changes the base year for calculating inflation rebates from 2021 to 2016, which would capture more years of price increases and potentially result in larger rebate amounts

Modifies how drug units are counted for rebate calculations by using billing units and excluding units already covered under Medicaid, the 340B drug discount program, or other rebate programs to prevent double-counting

Part B drug amendments take effect for calendar quarters beginning on or after January 1, 2026

Part D drug amendments take effect for applicable periods beginning on or after October 1, 2025