CMS proposed rulemaking that would codify and tighten the Inflation Reduction Act’s Medicare Drug Price Negotiation Program, including modifications to the “fixed combination drug” policy. The proposed changes target how drugs are grouped for negotiation and could affect strategies that extend blockbuster lifecycles. Separate reporting also indicates the rules may intersect with formulation choices for high-spend oncology biologics, including potential treatment of subcutaneous versions if biosimilar competition changes the selection logic. CMS said it intends to close what it called a “loophole,” while allowing biosimilar-driven deselection mechanics. For biotech and pharma, the immediate impact is planning around pricing eligibility and potential interchangeability of formulations as patents and biosimilar entry timelines evolve.