HR5526

Introduced on September 19, 2025, HR5526 amends Section 351(k) of the Public Health Service Act to eliminate the requirement that biosimilar applicants provide supplementary interchangeability data. Under current law, the FDA must make a separate interchangeability determination before a biosimilar can be substituted for its reference product at the pharmacy level without prescriber intervention. This bill would deem any FDA-approved biosimilar as automatically interchangeable, collapsing a costly, time-consuming regulatory step that currently adds 12-18 months and significant clinical trial expense to biosimilar development. The bill is in early legislative stages — referred to the House Committee on Energy and Commerce and has a companion bill (S1954) in the Senate. With 6 cosponsors and a lead sponsor from the majority party (Rep. Pfluger, R-TX), the bill has a plausible path in the 119th Congress but remains early-stage. The bill does not authorize or appropriate any federal funding — it is purely a regulatory reform measure that reduces compliance costs for biosimilar manufacturers. Structural winners are pure-play biosimilar and generic manufacturers with established biosimilar pipelines: Viatris ($VTRS) and Teva ($TEVA). These companies benefit from reduced R&D costs, faster time-to-revenue, and automatic pharmacy-level substitution that accelerates market share erosion of innovator biologics. Structural losers are innovator biologic manufacturers who rely on interchangeability barriers to protect market share: Amgen ($AMGN), Johnson & Johnson ($JNJ), and Biogen ($BIIB). The bill does not directly affect drug pricing or reimbursement — it changes the substitution rule, which governs competitive dynamics at the pharmacy counter. Real market data from April 2026 confirms investors are already pricing in this regulatory shift. $VTRS trades at $15.08, up 11.55% over 30 days, while $TEVA trades at $35.46, up 17.73% over the same period. Innovators show weakness: $AMGN at $344.44, down 2.11% over 30 days; $JNJ at $229.89, down 5.95%; and $BIIB at $190.99, up 4.18% but primarily driven by Alzheimer's pipeline news rather than biologic exposure. The price divergence between biosimilar producers and innovators over the past month suggests the market is assigning a measurable probability to the bill's passage in 2026. Remaining legislative steps: the bill must pass through the House Energy and Commerce Committee, receive a floor vote in the House, and then companion bill S1954 must do the same in the Senate via HELP Committee. Passage in 2026 is possible but not guaranteed, especially in an election year. If passed, the implementation timeline would be immediate upon enactment, as the bill does not include a delayed effective date.