What Is a Biosimilar?

A complete patient guide to FDA-approved biosimilar medications

Quick Answer

A biosimilar is an FDA-approved biological product that has been demonstrated to be highly similar to an already-approved reference biologic, with no clinically meaningful differences in safety, purity, or potency. Biosimilars are not generic drugs — they are complex proteins that cannot be exactly copied, but they are rigorously tested to ensure they work the same way.

Biosimilar vs Generic Drug: Key Differences

Feature	Generic Drug	Biosimilar
Made from	Chemical synthesis	Living cells (bacteria, yeast, mammalian)
Identical to original?	Yes — chemically identical	Highly similar — not identical (complex proteins cannot be exactly copied)
FDA approval pathway	Abbreviated New Drug Application (ANDA)	Biologics License Application (BLA) — 351(k) pathway
Clinical data required	Bioequivalence studies only	Extensive analytical, functional, PK/PD, and clinical data
Cost vs original	Typically 80–90% lower	Typically 15–35% lower list price

How FDA Approves Biosimilars

The FDA approves biosimilars through a rigorous stepwise process called the "totality of evidence" approach. Manufacturers must demonstrate biosimilarity through:

Extensive structural analysis — comparing the molecular structure of the biosimilar to the reference product using advanced analytical techniques
Functional testing — demonstrating the biosimilar behaves the same way in laboratory studies
Animal studies — where necessary for safety assessment
Human pharmacokinetic/pharmacodynamic studies — confirming comparable drug levels and effects in the body
Clinical immunogenicity studies — ensuring the biosimilar does not trigger more immune reactions than the reference product
Clinical trials — comparative clinical studies confirming similar efficacy and safety

FDA-Approved Biosimilars Available in 2026

Reference Biologic	Biosimilars Approved	Conditions
Humira (Adalimumab)	Hadlima, Hyrimoz, Cyltezo, Abrilada, Yusimry, Idacio, Hulio, Simlandi	RA, Crohn's, UC, Psoriasis, PsA, AS, HS, Uveitis
Remicade (Infliximab)	Inflectra, Renflexis, Avsola, Ixifi, Zymfentra	RA, Crohn's, UC, PsA, AS, Psoriasis
Stelara (Ustekinumab)	Wezlana, Selarsdi, Otulfi, Imuldosa, Steqeyma	Psoriasis, PsA, Crohn's, UC
Enbrel (Etanercept)	Eticovo, Erelzi	RA, Psoriasis, PsA, AS
Actemra (Tocilizumab)	Tyenne, Tofidence	RA, Giant Cell Arteritis
Orencia (Abatacept)	Orencia biosimilars in development	RA, PsA

Yes. The FDA requires biosimilars to demonstrate no clinically meaningful differences in safety, purity, and potency compared to the reference biologic. Multiple clinical trials, real-world evidence studies, and post-marketing surveillance data support the effectiveness of approved biosimilars for their approved indications.

For FDA-designated interchangeable biosimilars, your pharmacist can substitute without a new prescription. For non-interchangeable biosimilars, a prescriber authorization is typically required. BiologicHealthPlus will coordinate with your prescriber to ensure any switch is safe, properly authorized, and insurance-covered.

Biosimilar list prices are typically 15–35% lower than the reference biologic. However, your actual out-of-pocket cost depends on your insurance formulary and available copay programs. In some cases, the original biologic may actually cost you less because it has a stronger manufacturer copay program. BiologicHealthPlus compares all options on your specific plan to find the most affordable choice.

An interchangeable biosimilar has met additional FDA standards demonstrating it can be substituted for the reference product without the prescriber's intervention — similar to how generic drugs work. Interchangeable biosimilars must show that switching back and forth between the biosimilar and reference product does not produce additional risks compared to staying on either product alone.

💊 BiologicHealthPlus Carries Both Biologics and Biosimilars

We compare all available options on your specific insurance plan and identify the most affordable choice — whether that's the reference biologic or a biosimilar. Prior authorization, copay enrollment, and free delivery included.

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📚 Sources & Further Reading

Content developed with reference to leading health organizations, peer-reviewed research, and FDA prescribing information.

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Biosimilar BasicsFDA

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BiosimilarWikipedia

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Biosimilar ScienceNIH/NCBI

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Medicare Biosimilar CoverageCMS

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WHO Biosimilar GuidelinesWHO

Medical Disclaimer: Educational content reviewed by the BiologicHealthPlus Clinical Team. Consult your healthcare provider for personalized advice. Last reviewed: August 2026.

Disclaimer: Educational information only. Last updated: July 2026 by the BiologicHealthPlus Clinical Team.