Biosimilars: What You Should Know

Woman receiving infusion therapy from nurse

If you are taking a biologic therapy, such as infliximab (Remicade®), adalimumab (Humira®), vedolizumab (Entyvio®), or ustekinumab (Stelara®), to treat inflammatory bowel disease (IBD), you may have heard about, or are curious about, biosimilars.


Biologic therapies are complex proteins made in live cells that target part of your immune system.


Biosimilars are designed to be near identical copies of approved biologic therapies. Given the complexity of drug design, biosimilars cannot be exact copies of biologic therapies, but still contain the same active ingredient, mechanism of action (how they work), and dosing. Here are some key points to know and remember about biosimilars:  

  • Biosimilars are just as safe and effective as the original biologic therapy. There are no clinically meaningful differences. 

  • Biosimilars are taken in the same form (injection or intravenous) and dose as the related biologic medication (also known as the reference product). 

  • Biosimilars are carefully reviewed and approved by the Food and Drug Administration (FDA) and are carefully monitored on an ongoing basis to treat IBD.   

To learn about all available biosimilars (including those not yet available in the US), visit the IBD Medication Guide.


Special biosimilar terminology  

When researching biosimilars and/or talking to your healthcare provider, you may hear common terms used to describe biosimilars and biologic therapies. Here is what you should know:

  • Reference product: This is the biologic product already approved by the FDA in which the biosimilar product is compared to. For example, the reference product may be infliximab or adalimumab. 
  • Switching: Switching refers to changing between a reference product and a biosimilar, or between biosimilars, with no loss of effectiveness and no meaningful differences in treatment or safety. 
  • Interchangeability: Interchangeability is designated by the FDA and means the biosimilar is considered interchangeable with the reference product. Medications provided this designation allow for pharmacists to substitute the biosimilar for the reference product when ordered without requiring any action from the clinician. 

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What is a Biosimilar?

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Biosimilars: Terms to Know

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Biosimilars: Safety and Efficacy

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Biosimilars: Cost and Coverage

Frequently asked questions

Are biosimilars the same thing as generic medications?

In short, no.  

A generic medication is an exact copy of a small molecule drug (ex: acetaminophen is the generic for the brand name Tylenol®). A small molecule drug is very easy to produce and copy because it has a simple chemical structure.  

Biologics, on the other hand, are large, intricate molecules that are produced in living cells from highly specialized ingredients using a complex process with many precise steps. Even though the same exact process is followed every time the medication is made, there may be slight changes from batch to batch because these products are made by living cells. Thus, producing an exact copy of a biosimilar and reference product is not possible.  For this reason, biosimilars cannot be considered generics. However, biosimilars still contain the same active ingredient and mechanism of action as the reference product. 

When a patent for a reference biologic expires, companies may then develop biosimilars. However, biosimilars are not the same as generic medications.  

Are biosimilars safe?

Yes. Studies have shown that there are no meaningful differences in safety or quality between a reference product and its biosimilar. Biosimilars are FDA approved after thorough review of data, studies, and tests that confirm their high similarity to the reference product. The FDA also continually monitors all medication quality during production and throughout their period of availability to patients.

What is the FDA approval process for a biosimilar?

All FDA-approved biologic products, including biosimilars, go through rigorous testing to ensure the efficacy, safety, and quality.  A biosimilar manufacturer must prove the product’s biosimilarity through scientific data compared to the reference/originator product and may also rely in part on the FDA’s determination of safety and effectiveness for the reference product for approval.  

Given that the main goal for approval is to demonstrate that biosimilars are highly similar to the reference product with no clinically meaningful differences, biosimilar manufacturers do not need to perform as many expensive tests and trials as the reference product manufacturer does; therefore, the approval process is a bit shorter and the biosimilar is generally less expensive to produce. 

How long have biosimilars been around?

The first IBD biosimilars were approved in Europe in 2006, Canada in 2009, and the United States in 2015. In addition to IBD, biosimilars are also used to treat other medical conditions such as diabetes, rheumatoid arthritis, cancer, osteoporosis, psoriasis, and more.  

Why would I take a biosimilar over a biologic?

At this time, medication choices for IBD patients may be dictated by insurance company’s preference for which medications to cover. As the FDA approval pathway is shorter for biosimilar products, the cost of making the biosimilar is less expensive. It is our hope that patients who choose to take biosimilars will benefit from these manufacturing cost savings through lower payments or co-pays/premiums and switching to biosimilars should result in less – not more out-of-pocket expenses.   

Which biosimilars are approved to treat IBD?

The FDA has approved specific biosimilar medications for IBD, but not every approved biosimilar is available currently in the US market. Here is a list of the IBD biosimilars that are currently FDA approved:

  • Infliximab-abda (Renflexis®) 

  • Infliximab-axxq  (Avsola™) 

  • Infliximab-dyyb (Inflectra®) 

  • Adalimumab-afzb (Abrilada®)

  • Adalimumab-atto (Amjevita™)

  • Adalimumab-adbm (Cyltezo®)

  • Adalimumab-aqvh (YUSIMRY™)

  • Adalimumab-adaz (Hyrimoz®)

  • Adalimumab-bwwd (Hadlima™)

  • Adalimumab-aaty (Yuflyma®)

  • Adalimumab-fkjp (Hulio®)

  • Adalimumab-aacf (Idacio®)

  • Ustekinumab-auuf (Wezlana™)

To learn about all available biosimilars, visit the IBD Medication Guide

I just received a notification from my insurance company that they will no longer be covering my biologic medication and I will need to switch to a biosimilar. What questions should I ask my healthcare team?

If you received a change of medication notice from your insurance company, you probably have a lot of questions. Here are some questions to ask your healthcare team as well as your insurance company: 

  • Why is my treatment changing? 

  • When is this change going to take effect? 

  • What is the name of my new treatment? 

  • What can I expect with this change? 

  • Does this hospital/infusion center/medical group provide this treatment to patients? 

  • What is the expected cost of the new treatment? 

  • Can I receive co-pay assistance and support services if I switch to a biosimilar? 

  • Who do I contact if I have questions about medication administration? 

Can I appeal my insurance company’s decision?

It is understandable that you or your loved one may feel unsure about switching to biosimilars- especially if your current treatment plan is working. It is encouraged that you share your concerns with your healthcare provider and ask them about whether an appeal may be right for you. The appeals process can take time and may cause long delays that could impact your care. It is important that you speak with your healthcare team about how the process may affect your treatment plan and go over all possible options.  

For more information about insurance appeals please see What to do if denied coverage

How does the switch take effect?

Biosimilar medications are given using the same administration route as their reference product. Therefore, you should receive your treatment the same way you did before, i.e. infusion or injection. Talk to your healthcare provider if you have specific questions about how your treatment is administered.  

Is it safe to switch from one reference product to a biosimilar or from biosimilar to another biosimilar?

Several studies have demonstrated that a single switch from a reference product to a biosimilar or from a biosimilar to another biosimilar is acceptable. Studies on several switches (e.g., switching from a reference product to a biosimilar to another biosimilar or among biosimilars) are currently underway and thus far, appear to show comparable efficacy and safety. 

Are biosimilars safe for pediatric IBD patients?

Research shows that there is no meaningful difference in safety, efficacy, or quality between a reference product and its biosimilar for both adult and pediatric IBD patients. Overall, the use of biosimilars for treatment of pediatric IBD patients continues to need more research, as it has not been studied as much as within the adult IBD population. However, pediatric patients generally have a more severe disease presentation and poor prognosis. Therefore, the use of biosimilars and multiple switches should only be considered in pediatric patients who are in remission.  If you receive a notification from your insurance company about switching your child’s current medication to biosimilars, you should contact your child’s healthcare team to discuss further.  

Be Your Own biosimilar advocate 

You have the right to know about your available treatment options and to be involved in making decisions with your healthcare team.


The Crohn's & Colitis Foundation believes that patients and their doctors should work together when deciding which treatment to choose, and that no decision should be made by a pharmacist or medical insurance company without the consent of the patient and doctor. 

Resources on biosimilars

Visit the Foundation’s resources about IBD, medications, and insurance information: 

The FDA has several resources on biosimilars. 

If you need more information, or can’t find what you are looking for, please reach out to the Crohn’s & Colitis Foundation’s IBD Help Center


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Biosimilars Position Statement

Fact sheet

Biosimilars position statement January 10, 2024...

Biosimilars position statement January 10, 2024.pdf