S-1414-119
Placed on Senate Legislative Calendar under General Orders. Calendar No. 520.
Sponsored by Rand Paul (R-KY)
What it does
This bill would amend the Public Health Service Act to change what clinical studies the FDA can require when a drug company applies to sell a biosimilar — a near-copy of a complex biological drug. Under current law, the FDA can require studies assessing immunogenicity (how the body's immune system reacts), pharmacodynamics (how the drug affects the body), and comparative clinical efficacy (how well it works compared to the original). This bill would make pharmacokinetics (how the drug moves through the body) and immunogenicity standard requirements, while making pharmacodynamics and efficacy studies optional — the FDA could only require them if it provides written justification to the applicant at a specific early stage of the review process, and could not later add that requirement without written agreement or a documented scientific reason.
Who benefits
Generic and biosimilar drug manufacturers, who would face a narrower and more predictable set of required clinical studies, potentially reducing development costs and timelines. Patients who use high-cost biological drugs (such as insulin, cancer treatments, or autoimmune therapies) who may gain access to lower-cost biosimilar alternatives sooner. Insurers and pharmacy benefit managers who could negotiate lower prices if more biosimilars reach the market. Employers and government health programs (Medicare, Medicaid) that pay for biological drugs and would benefit from increased price competition.
Who is hurt
Brand-name biological drug manufacturers, who benefit from the current high bar for biosimilar approval and whose market share and pricing power could be reduced by faster biosimilar entry. Patients who may be exposed to biosimilars that have not undergone the full range of clinical testing previously available to the FDA. Physicians and clinical researchers who rely on comprehensive comparative efficacy data to make prescribing decisions. The FDA itself would lose some discretionary authority to require additional studies, potentially constraining its ability to respond to product-specific safety signals during the review process.
Supporters argue
Supporters argue that the current biosimilar approval pathway imposes redundant clinical testing requirements that delay patient access to affordable medicines without meaningfully improving safety. They contend that pharmacokinetic and immunogenicity data — which would remain required — are already sufficient to demonstrate biosimilarity for most products, and that the FDA's ability to require additional studies when scientifically justified is preserved. They point to the fact that biosimilars in the U.S. cost 15–35% less than reference biologics on average, and that faster approvals could generate billions in savings for patients and federal health programs.
Opponents argue
Opponents argue that biological drugs are far more complex than small-molecule generics, and that immunogenicity and efficacy differences between a biosimilar and its reference product may not be detectable without the full suite of clinical studies the FDA currently has discretion to require. They contend that restricting the FDA's ability to demand pharmacodynamics or efficacy data — especially by locking in that determination early in the review process — could prevent the agency from responding to emerging safety concerns, potentially exposing patients to products whose real-world performance has not been adequately characterized relative to the original drug.
Constitutional context
Congress has broad authority to regulate drug approval standards under the Commerce Clause (Art. I, §8, cl. 3) and the Necessary and Proper Clause (Art. I, §8, cl. 18). This bill modifies an existing statutory framework rather than creating new federal mandates, so no major constitutional tension is apparent. However, post-Loper Bright (2024), any FDA regulations implementing this bill's new procedural requirements would be subject to independent judicial review rather than automatic deference, meaning courts would assess whether the agency's interpretations of the amended statute are correct on their own terms.
Checks and balances
Congress narrows the FDA's discretionary authority over biosimilar clinical study requirements; the FDA retains the ability to require additional studies with written scientific justification; federal courts would independently review any FDA implementation rules under the post-Loper Bright standard.
Historical precedent
The Biologics Price Competition and Innovation Act of 2009 (part of the ACA) created the current biosimilar approval pathway under Section 351(k) of the Public Health Service Act, and subsequent FDA guidance has shaped what clinical data is required — this bill would be the first statutory modification to those clinical study requirements.