S. 4323 — Ensuring Access to Lower-Cost Medicines for Seniors Act

This section requires prescription drug plan (PDP) sponsors and Medicare Advantage organizations offering Medicare Advantage-Prescription Drug (MA-PD) plans using formularies under Medicare Part D, for plan years beginning on or after January 1, 2028, to (1) include on the formulary each Part D generic drug with a wholesale acquisition cost (WAC) lower than its Part D reference drug if the reference drug is included, and at least one Part D biosimilar biological product with a lower WAC than its Part D reference biological product if the reference biological product is included and such a biosimilar is available; (2) make such determinations and implement formulary changes in accordance with uniform requirements established by the Secretary (quarterly during a plan year, with prompt implementation); and (3) prohibit access limits (e.g., prior authorization, utilization management, or step therapy) on required generics or biosimilars that are more restrictive than those on the corresponding reference drug or biological product. The section further requires such PDP sponsors and MA-PD organizations, for plan years beginning on or after January 1, 2028, to establish at least one formulary cost-sharing tier exclusively for Part D generic drugs and Part D biosimilar biological products with either no cost-sharing or a copayment at least $20 lower than the lowest branded drug tier (not below zero)—using a copayment amount if the branded tier is copayment-based or an actuarially equivalent amount if coinsurance-based, as determined under specified processes.