Biosimilars are biological products highly similar to existing, approved medicines. While not exact copies, they are developed to have comparable quality, safety, and effectiveness to their reference products, offering additional treatment options.
Understanding Biosimilars
Biological products, or biologics, are complex medicines derived from living organisms, such as cells or tissues. They are much larger and more intricate in structure than traditional chemically synthesized drugs. Examples include vaccines, therapeutic proteins, and monoclonal antibodies, which treat conditions like cancer, autoimmune diseases, and diabetes.
Biosimilars differ significantly from generic drugs. Generic drugs are chemically identical copies of small-molecule drugs, ensuring the same active ingredients and effects. In contrast, biosimilars are “highly similar” to their reference biologics, not identical, due to inherent biological variability. This distinction requires biosimilars to undergo a more comprehensive approval process than generics.
A “reference product” is the original U.S. Food and Drug Administration (FDA)-approved biological product against which a proposed biosimilar is compared. The biosimilar must demonstrate no clinically meaningful differences from this reference product in terms of safety, purity, and potency.
Approved Biosimilars: The Current Count
As of July 16, 2025, the U.S. Food and Drug Administration (FDA) has approved 72 biosimilars. This includes 10 approvals between January and April 2025 alone.
These approvals span various therapeutic areas, offering alternative treatment options. For instance, biosimilars exist for reference products like Humira (adalimumab) and Remicade (infliximab) for autoimmune disorders. Oncology also has approved versions of Avastin (bevacizumab) and Neulasta (pegfilgrastim).
Recent 2025 approvals include biosimilars referencing Stelara (ustekinumab) for psoriasis and Crohn’s disease, and denosumab for osteoporosis. Biosimilars for Actemra (tocilizumab) and Xolair (omalizumab) have also been approved. The most recent approval as of July 15, 2025, was Kirsty (insulin aspart-xjhz), referencing Novolog.
The Rigorous Approval Process
U.S. biosimilar approval follows a stringent scientific and regulatory pathway established by the Biologics Price Competition and Innovation Act (BPCI Act) of 2009. This legislation created an abbreviated approval pathway under Section 351(k) of the Public Health Service Act (PHSA). The goal is to demonstrate a biosimilar is “highly similar” to its reference product, without requiring independent proof of safety and effectiveness.
Manufacturers must submit a comprehensive application, including extensive analytical studies that compare the biosimilar’s structure and function to the reference product. Non-clinical and clinical studies are also required to confirm no clinically meaningful differences. These clinical studies typically assess pharmacokinetics, pharmacodynamics, immunogenicity, and clinical efficacy.
A higher designation, “interchangeability,” can be granted to some biosimilars. An interchangeable biosimilar is expected to produce the same clinical result as the reference product in any given patient and can be substituted at the pharmacy level without intervention from the prescribing healthcare provider. This designation historically required additional switching studies, but recent draft guidance from the FDA may allow for interchangeability based on comparative analytical and clinical data alone.
Why Biosimilar Approvals Matter
Biosimilar approvals expand patient access to biological therapies. By introducing more affordable options, biosimilars reduce the financial burden of high-cost treatments. This increased affordability can lead to improved medication adherence and earlier treatment initiation, particularly for chronic and life-threatening conditions.
The introduction of biosimilars fosters competition within the pharmaceutical market. This competition can drive down prices for both the biosimilars and their reference products, resulting in significant cost savings for patients, insurance providers, and healthcare systems overall. Estimates suggest substantial savings to the U.S. healthcare system due to biosimilar use.
Ultimately, biosimilars contribute to the sustainability of healthcare systems by making expensive biological treatments more accessible and economical. They provide a wider array of treatment choices, allowing healthcare providers greater flexibility in tailoring therapies to individual patient needs while managing healthcare expenditures.