The Biologics Price Competition and Innovation Act (BPCIA), enacted in 2010 as part of the Patient Protection and Affordable Care Act (ACA), established an abbreviated licensure pathway for biosimilars and interchangeable biologics. The goal was to promote competition, reduce biologic drug costs, and expand patient access to life-saving therapies without compromising safety or effectiveness.
As of 2025, the BPCIA remains a cornerstone of U.S. biosimilar policy, with strong bipartisan support across Congress and broad endorsement from healthcare providers, payers, and patient groups. The FDA continues to apply a rigorous, science-based regulatory approach to ensure biosimilars meet the same high standards as their reference biologics.
Definition of a Biosimilar (FDA, 2025)

• A biosimilar is a biological product that is highly similar to a previously FDA-licensed reference product, with no clinically meaningful differences in terms of safety, purity, and potency. Minor differences in inactive ingredients are permitted, provided they do not affect clinical outcomes.
• As of early 2025, the FDA has approved more than 45 biosimilars, spanning therapeutic areas such as oncology, rheumatology, endocrinology, and ophthalmology — demonstrating broad uptake across the U.S. healthcare system.

Definition of Interchangeability (FDA, 2025)

• An interchangeable biosimilar meets all biosimilarity requirements and also demonstrates that it can be expected to produce the same clinical result as the reference product in any patient. For products used more than once, it must also show that switching between the biosimilar and reference product does not increase risks related to safety or efficacy.
• If a product is granted interchangeability status, it may be substituted by a pharmacist for the reference product without needing the prescriber’s approval, subject to individual state substitution laws. As of 2025, the FDA has granted interchangeability designations to multiple biosimilars, including those for adalimumab, insulin glargine, and ranibizumab, further supporting real-world adoption.

The BPCIA framework has proven essential in lowering costs, expanding treatment options, and enhancing biologic drug access across the U.S., while maintaining the FDA’s high bar for product quality, safety, and efficacy.
The biosimilar regulatory system in the U.S. ensures that every approved biosimilar undergoes rigorous review, maintaining high standards while fostering a competitive market for biologic therapies.

Manufacturers seeking to market a biosimilar or interchangeable biologic in the United States must submit a 351(k) Biologics License Application (BLA) under the Public Health Service Act, a regulatory framework established by the Biologics Price Competition and Innovation Act (BPCIA).

• As of 2025, the FDA’s review process remains rigorous and science-driven, designed to ensure that biosimilar products meet the highest standards of safety, purity, and potency.
•  To qualify for biosimilar approval under 351(k), the application must demonstrate that:
• The biological product is biosimilar to an FDA-licensed reference product.
• It uses the same mechanism(s) of action for the proposed condition(s) of use (as far as the mechanism is known).
• The condition(s) of use proposed in labeling have been previously approved for the reference product.
• The route of administration, dosage form, and strength are the same as the reference product.
• The manufacturing facility complies with Good Manufacturing Practices (GMP) to ensure consistent safety, identity, strength, quality, and purity of the biosimilar product.

Data requirements to support biosimilarity include:

• Comprehensive analytical studies to confirm that the product is highly similar to the reference biologic, with allowance for minor differences in inactive ingredients.
• Animal studies, including toxicology assessments (if required).
• Clinical studies, including:
• Immunogenicity evaluation
• Pharmacokinetics (PK) and Pharmacodynamics (PD)
• At least one comparative clinical study (unless waived) that demonstrates no clinically meaningful differences from the reference product.
• Note: In recent years, the FDA has shown increasing flexibility in waiving certain animal or clinical study requirements when a strong analytical and PK/PD data package is provided.
• For Interchangeability Designation, the application must also show:
• The biosimilar is already approved as a biosimilar to the reference product.
• It can be expected to produce the same clinical result in any given patient.
• For products used more than once, the safety or efficacy risk of switching between the biosimilar and the reference product is not greater than continuing with the reference product alone.
• Once designated interchangeable, the product may be substituted at the pharmacy level in accordance with state pharmacy laws.

FDA’s Flexibility Under 351(k):

• The FDA maintains the authority to determine, on a case-by-case basis, that certain elements of the biosimilarity or interchangeability data package may not be necessary, depending on the product’s complexity, clinical profile, and the strength of comparative data provided.
• This tailored regulatory approach continues to evolve, making it more feasible for manufacturers to bring safe, effective, and affordable biosimilars to market—helping improve access for patients across the U.S.

• Upon the submission of a complete 351(k) Biologics License Application (BLA), the U.S. Food and Drug Administration (FDA) begins a rigorous, stepwise evaluation process to determine whether the proposed product is:
• Biosimilar to a licensed reference product, or
• Interchangeable, meaning it can be substituted at the pharmacy level without prescriber intervention (subject to state laws).

FDA Review Process:

• Biosimilarity Assessment
• The FDA examines the totality of evidence, including analytical data, pharmacokinetics/pharmacodynamics (PK/PD), immunogenicity, and (if needed) clinical trial data, to ensure that the biosimilar is highly similar to the reference product and without clinically meaningful differences.

Manufacturing Facility Inspection

• As of 2025, the FDA continues to inspect the biosimilar manufacturing sites to ensure they meet Good Manufacturing Practice (GMP) standards. These inspections are equally stringent as those for originator biologics under 351(a).
• Remote inspections and risk-based assessments (introduced during the COVID-19 pandemic) are still occasionally used where appropriate, based on international cooperation and mutual recognition agreements.

Product Licensure

• If the application and manufacturing facility meet all regulatory requirements, the FDA licenses the biosimilar or interchangeable biologic for the same indications as the reference product, unless otherwise limited.

Use of Foreign Comparator Products

• Manufacturers may submit data derived using a foreign-approved comparator (i.e., a reference product licensed in Europe or other ICH countries) in certain circumstances. However:
• The FDA must be convinced that the foreign comparator is analytically and clinically comparable to the U.S.-licensed reference product.
• Bridging studies or scientific justification is often required to establish equivalency between the non-U.S. comparator and the FDA-approved reference.
• As of 2025, the FDA continues to support global harmonization by accepting such data when supported by robust scientific rationale and bridging analytics.

Reference Product Definition

• The reference product used for comparison must always be a single biological product previously licensed under Section 351(a) of the Public Health Service Act. It serves as the foundation against which biosimilarity is measured in any 351(k) application.
• Even if comparator data is drawn from international sources, the reference standard for regulatory approval in the U.S. must be the FDA-approved product.
• 2025 Trends and Enhancements
• Greater clarity on interchangeability requirements: FDA guidance now better outlines how switching studies can be waived in some circumstances.
• Expedited biosimilar review programs (akin to Fast Track or Breakthrough Therapy designations) are being piloted for biosimilars addressing critical drug shortages or high-cost therapies.
• Increased use of real-world evidence (RWE): Post-market surveillance and pharmacovigilance continue to shape biosimilar confidence and expansion.