This legislation proposes amendments to Medicare Part D, specifically targeting cost-sharing for chronic care drugs, with changes taking effect for plan years beginning on or after January 1, 2027. A central provision dictates that for these specified drugs, cost-sharing below the annual deductible cannot exceed the drug's net price . Furthermore, for costs incurred between the annual deductible and the out-of-pocket threshold, any coinsurance amount must be calculated as a percentage of this net price . The bill defines "net price" as the negotiated price less all manufacturer price concessions received or expected by the plan or pharmacy benefit manager. The bill specifies a list of drug categories that qualify as "chronic care drugs," including blood glucose regulators, certain anti-inflammatories, bronchodilators, anticoagulants, and cardiovascular agents. An exception is made for plans where cost-sharing is a fixed copayment not tied to the drug's price or cost. Additionally, the legislation includes conforming amendments to ensure that copayment amounts for low-income individuals receiving chronic care drugs do not exceed the applicable cost-sharing under their specific Medicare Part D plan. The Secretary of Health and Human Services is directed to implement these amendments through interim final regulations.