What the New FDA Draft Guidance Proposes
On March 9, 2026, the FDA issued new draft guidance to reduce the time and cost of bringing biosimilars to market. The document, titled “New and Revised Draft Q&As on Biosimilar Development and the BPCI Act (Revision 4),” focuses on streamlining clinical pharmacokinetic (PK) testing requirements. This move marks the latest step in the current administration’s effort to lower biologic drug costs for American patients.
The FDA also withdrew its 2015 final guidance on demonstrating biosimilarity to a reference product, stating it no longer reflects the agency’s current thinking.
How PK Studies Work and Why Costs Matter
Understanding Pharmacokinetic Testing
PK studies measure how the body absorbs, distributes, and eliminates a drug. Traditionally, developers have used these studies to demonstrate that a biosimilar behaves comparably to its reference biologic product. They are a core requirement in the biosimilar approval process.
However, these studies are costly and time-consuming. Furthermore, advances in analytical technology now offer more precise tools to evaluate drug similarity. Therefore, the FDA has determined that certain PK testing requirements are redundant.
Key Changes in Testing Requirements
Removal of the Three-Way PK Study Requirement
Previously, developers needed to conduct a three-way PK study comparing the proposed biosimilar with both a US-licensed reference product and a non-US-licensed comparator product. Under the new guidance, this requirement no longer applies in every case.
Use of International Comparator Data
Developers may now submit clinical data from comparator products approved outside the US, without providing additional data from a three-way PK study. This change applies when the approach is scientifically justified. Consequently, companies with international development programs can move faster through the US approval process.
Streamlining Unnecessary PK Testing
The guidance recommends eliminating PK testing requirements that are scientifically redundant. When a comparative analytical assessment (CAA) already demonstrates high similarity between a proposed biosimilar and its reference product, additional clinical PK studies may not be necessary.
Impact on Biosimilar Development Costs
Up to 50% Reduction in PK Study Costs
The FDA estimates that these changes could save biosimilar developers up to 50% of their PK study costs. That translates to approximately $20 million per program — a significant reduction that could encourage more companies to invest in biosimilar development.
This new guidance builds on earlier action from October 2025, when FDA Commissioner Marty Makary announced draft guidance to reduce unnecessary comparative efficacy studies (CES). Those CES studies typically take one to three years and cost an average of $24 million.
Why Biologic Pricing Is a National Concern
Biologic medicines treat serious conditions including autoimmune diseases, cancer, and rare disorders. Yet despite accounting for only 5% of all prescriptions in the US, biologics represent 51% of total drug spending. Many of these drugs cost hundreds of thousands of dollars per year. As a result, access remains limited for many patients.
The Broader Push to Expand Biosimilar Access
A Series of Regulatory Actions
This March 2026 guidance is part of a broader initiative that began in October 2025. At that time, the FDA proposed removing comparative efficacy studies from biosimilar approval requirements. The agency also proposed that all approved biosimilars should receive interchangeability status, making it easier for pharmacists to substitute them at the point of dispensing.
Together, these reforms align the biosimilar approval pathway more closely with the generics model. Moreover, Commissioner Makary has stated his intention to finalize both the biosimilarity and interchangeability draft guidance documents within the first half of 2026.
Competing with European Regulators
The FDA is also working to close the approval gap with the European Medicines Agency (EMA). In 2025, the EMA approved 22 more biosimilars than the FDA. However, the US saw progress in 2024, when 19 biosimilars received FDA approval — a sharp increase from five in 2023.
The Biosimilar Void: A Persistent Challenge
Despite these positive regulatory steps, a deeper structural problem remains. Between 2025 and 2034, approximately 118 biologic molecules representing nearly $232 billion in US sales are expected to lose patent protection. Yet only about 10% of these biologics currently have biosimilars in active development.
This gap is known as the “biosimilar void.” Several factors contribute to it:
- Manufacturing complexity — Advanced biologics require specialized production expertise
- Limited ROI for niche products — Small patient populations reduce revenue potential
- Market uncertainty — Shifting reimbursement rules create hesitation among investors
- Prolonged timelines — Even with streamlined guidance, development can take nearly a decade
The pathway to addressing the biosimilar void begins with regulatory modernization. While the new FDA draft guidance is a major step forward, the challenge extends well beyond regulatory barriers.
Industry and Policy Response
Strong Bipartisan Support
The new guidance has drawn broad support from policymakers and industry groups. HHS Secretary Robert F. Kennedy Jr. described earlier regulatory requirements as burdened by “sky-high costs and endless red tape.” He welcomed the new guidance as replacing “bureaucracy with science.”
The Biosimilars Forum called the earlier October 2025 guidance “momentous.” Executive Director Juliana M. Reed stated that biosimilars are “key to fixing America’s healthcare affordability crisis,” noting that nearly 30% of Americans have not taken prescribed medication due to unaffordable costs.
FDA’s Commitment to Lower Drug Costs
Commissioner Makary stated clearly: “Streamlining biosimilar development reflects our ongoing commitment to lowering drug costs for everyday Americans.” He added that the agency is embracing more precise analytical testing approaches than were used in the past.
With 82 biosimilars approved to date, the FDA continues to expand its regulatory experience — and its ambition. As biosimilar access grows, patients with cancer, autoimmune diseases, and other chronic conditions could gain more affordable treatment options.
