Definition
What Is a Biosimilar?
Last updated
A biosimilar is a biologic medication that the FDA has determined is highly similar to, and has no clinically meaningful differences from, an already-approved biologic medicine known as the reference product. Biosimilars are not exact chemical copies, since biologics are made from living sources rather than synthesized chemicals, but they are expected to work the same way in the body as the reference product.
How it affects what you pay
Biosimilars can offer a lower-cost path to an expensive biologic treatment, similar to how generics offer a lower-cost path to brand-name chemical drugs. The FDA notes that, similar to generics, biosimilars may cost less because their manufacturers can rely on the FDA's existing finding that the original biologic is safe and effective, rather than repeating the full original clinical trial program (FDA, Biosimilars Basics for Patients). Because many biologics fall into the specialty pharmacy category with high list prices, a biosimilar option, if one exists for your specific biologic, can represent a meaningful cost difference, though actual savings depend on your specific insurance formulary and plan design.
Example
Consider a hypothetical biologic medication used to treat a chronic condition, for which a biosimilar version has since been FDA-approved. A patient and their doctor might discuss switching to the biosimilar, which is expected to work the same way, potentially at a lower cost depending on the specific insurance plan's formulary tier for each option. This is a general illustration, not medical guidance for any specific condition or drug.
How biosimilars differ from generics
Both biosimilars and generics are compared against a reference product for FDA approval and go through a rigorous review process, but they differ in an important way: generics are typically made from synthesized chemical ingredients that can be essentially copied exactly, while biologics, and therefore biosimilars, are made from natural and living sources, which cannot be exactly copied (FDA, Biosimilars). This is why the FDA uses the term "biosimilar," meaning highly similar, rather than "generic," for these products.
Talking to your doctor about a biosimilar option
Switching from a biologic to its biosimilar is a decision that should involve your prescriber, since it may involve confirming interchangeability status and monitoring your response. Compare prescription prices on BetterBuyRx to see what pricing looks like for both the original biologic and any available biosimilar before that conversation. Our guide on generic vs brand-name medications touches on related cost-saving substitution concepts.
Checking availability
Not every biologic has a biosimilar version yet, since approval depends on the original biologic's patents and exclusivity periods expiring first. Search your medication on BetterBuyRx to see what's currently listed for your specific biologic medication.
Frequently asked questions
Is a biosimilar the same thing as a generic drug?
No. Biosimilars and generics are both lower-cost versions of an original FDA-approved product, but generics are chemically identical copies, while biosimilars are highly similar, not identical, versions of a biologic medicine, since biologics can't be exactly copied.
Are biosimilars as safe and effective as the original biologic?
The FDA states that biosimilars have no clinically meaningful differences from the original biologic, meaning patients can expect the same safety and effectiveness over the course of treatment.
Why might a biosimilar cost less than the original biologic?
Similar to generics, biosimilar manufacturers can rely in part on the FDA's existing finding that the original biologic is safe and effective, avoiding some of the cost of repeating full clinical development.
Sources
Compare prices & find savings
This page is for cost and savings education only. It is not medical advice. Talk to your doctor or pharmacist about your specific medications and coverage. Prices vary by pharmacy, location, quantity, and eligibility.
Related terms & guides
- What Is a Generic Medication?
Generic medication definition: how the FDA defines generics, why they usually cost less than brand-name drugs, and how to check availability.
- What Is a Brand-Name Drug?
Brand-name drug definition: how it differs from a generic, why it usually costs more, and how patents affect availability of lower-cost versions.
- What Is a Specialty Pharmacy?
Specialty pharmacy definition: what makes a drug 'specialty,' why these medications need extra handling, and how it affects your cost.