If your doctor or pharmacist has mentioned a "biosimilar" as an alternative to your biologic medication, you may have wondered: is this just a generic? The short answer is: biosimilars are the closest thing to generics for biologic drugs — but they are not identical in how they are made, approved, or substituted. Here is the complete comparison every patient needs.
What Is a Generic Drug?
A generic drug contains the same active ingredient as a brand name small-molecule drug (like a tablet or capsule), in the same dose and form, and is bioequivalent — meaning it reaches the bloodstream at the same rate and extent. Generics are approved through the FDA's ANDA process and typically cost 80–85% less than their brand equivalents.
Examples: atorvastatin (generic for Lipitor), sertraline (generic for Zoloft), metformin (generic for Glucophage)
What Is a Biosimilar?
A biosimilar is a biologic drug that is "highly similar" to an approved reference biologic (the brand-name biologic), with no clinically meaningful differences in safety, purity, or potency. Biologics are large, complex molecules — proteins, antibodies, and other compounds derived from living cells. Because of this complexity, true molecular identity is impossible; biosimilars are highly similar but not chemically identical.
Biosimilars are approved through the FDA's 351(k) pathway, which requires: structural and functional characterization, animal studies, clinical pharmacology data, and clinical evidence demonstrating biosimilarity. This is more extensive than the generic ANDA process but less extensive than a full biologic approval.
Examples: adalimumab biosimilars (Hadlima, Hyrimoz, Cyltezo) for Humira; trastuzumab biosimilars for Herceptin; etanercept biosimilars for Enbrel
Key Differences: Generics vs Biosimilars
| Factor | Generic Drug | Biosimilar |
|--------|-------------|-----------|
| Drug type | Small molecule | Biologic (large molecule) |
| Chemical identity | Identical to brand | Highly similar, not identical |
| Manufacturing | Standard chemistry | Complex cell culture process |
| FDA pathway | ANDA (abbreviated) | 351(k) (more extensive) |
| Approval evidence | Bioequivalence studies | Structural + clinical studies |
| Cost vs brand | 80–85% cheaper | 15–35% cheaper |
| Automatic substitution | AB-rated = pharmacist can substitute | Interchangeable = pharmacist can substitute |
The Cost Difference Explained
Generic drugs typically achieve 80–85% cost reduction because multiple manufacturers compete aggressively on price once patents expire. Biosimilars achieve 15–35% cost reduction — much less than generics — for several reasons:
1. Manufacturing complexity — biosimilars require living cell cultures and complex purification. High manufacturing costs limit price competition.
2. Clinical development costs — biosimilar development costs $100–250M, much more than generic development
3. Physician hesitancy — some prescribers are reluctant to switch stable patients on biologics, limiting market uptake
4. Patent thickets — reference biologics often have dozens of overlapping patents, complicating market entry
Interchangeable Biosimilars: The Highest FDA Designation
The FDA has a higher designation: interchangeable biosimilar. An interchangeable biosimilar has demonstrated that it can be expected to produce the same clinical result as the reference product in any given patient, and that switching between the reference and biosimilar does not increase safety or efficacy risk.
Why it matters: In most US states, pharmacists can automatically substitute an interchangeable biosimilar for the reference biologic without physician intervention — exactly like AB-rated generic substitution. Non-interchangeable biosimilars require a physician authorization to switch.
As of 2026, several adalimumab biosimilars (Cyltezo, Hadlima, Hyrimoz, Yusimry) have received interchangeable designation.
2026 Tariff: Both Are Fully Exempt
For the 2026 pharmaceutical tariff, generics and biosimilars are treated identically: both are fully exempt at 0%, regardless of manufacturer or country of manufacture. This is one of the most consequential aspects of the tariff — and a strong financial signal to patients considering a switch.
If you are on an expensive brand-name biologic and a biosimilar exists, the tariff exemption compounds the existing cost advantage. Use the drug search tool to check whether a biosimilar exists for your medication.
Upcoming Generic and Biosimilar Drugs
Patent expiries create a pipeline of upcoming generics and biosimilars. Key upcoming launches to watch:
- Keytruda biosimilars — pembrolizumab patents expire in phases through 2028–2036; biosimilar development is underway
- Dupixent biosimilars — dupilumab patents extend to ~2031+
- Jardiance generics — empagliflozin US patent protection extends to ~2025–2027 (generics may arrive soon)
- Eliquis generics — apixaban patents — some expired, generic entry being contested in court
Check the FDA Orange Book patent expiry dates for your specific drug to understand when generic competition may arrive.