In its Medicare Advantage and Part D Final Rule for 2025, the Centers for Medicare & Medicaid Services (CMS) announced that biosimilars can now be substituted as part of regular formulary maintenance changes. Treating all biosimilar substitutions as maintenance changes means that midyear formulary substitutions of biosimilars for their reference products would apply to all enrollees, including those already taking the reference product prior to the effective date of the change, following a 30-day advance notice to affected enrollees.

The change is consistent with longstanding requests from ASHP to encourage biosimilar adoption. However, this policy also has the potential to significantly increase patient cost sharing if pharmacists are not empowered to switch patients to the lower-cost biosimilar.

Tom Kraus, ASHP vice president of government relations, called for state action, noting, “State legislatures will need to move quickly to empower pharmacists to implement substitutions of lower-cost biosimilar products in order to avoid dramatic increases in patient cost sharing from this Medicare policy."

ASHP also supports S. 2305, the Biosimilar Red Tape Elimination Act, sponsored by Senators Mike Lee (R-UT), Ben Ray Luján (D-NM), Mike Braun (R-IN), and J.D. Vance (R-OH), which would accelerate biosimilar adoption by eliminating the need for clinically unnecessary switching studies that delay interchangeability.