What Are Biosimilar Treatments?

"Highly Similar" Products to Original Biologic Treatments

Biosimilars are a type of biologic therapy thought to work very similarly to an original biologic treatment. Thus, some people using original biologic agents might be able to switch to less expensive biosimilar products without having any problems. The term “similar biological medicinal product” was first used in 2001. Since then, the term has been shortened to “biosimilar.”

The first biosimilar approved by the FDA was for filgrastim in 2015. Since then, increasing numbers of biosimilars have been approved. But many people, including some health professionals, are confused about just what a biosimilar is and what it is not. 

What Are Biologic (Biological) Treatments? 

To understand biosimilars, it is helpful to understand a little about biologic treatments generally. Unlike traditional pharmaceutical drugs, biologic treatments are developed from some component of a living organism. For example, many modern biologic therapies derivatives of a certain type of protein.

Because of this, their structure is more complicated than traditional pharmaceutical medications. Most cannot be taken by mouth, and they are more sensitive to their storage conditions. Many, but not all, biologic treatments target some part of the immune system. 

Some biologic treatments, such as vaccines, have been available for many years. But in the past couple of decades, more and more biologic therapies have become available. These have revolutionized the treatment of many different diseases such as rheumatoid arthritis and inflammatory bowel disease. 

What Are Biosimilar Treatments?

“Biosimilars” refer to a specific type of biologic therapy. Specifically, they are biologic treatments that were designed to work in almost the same way as biological treatments already approved by the FDA (sometimes called “reference products.”) 

The FDA describes biosimilars as treatments that are “highly similar” to the original biologic that had been previously FDA approved. The FDA also asserts that such products must have “no clinically meaningful differences” from that original biologic treatment. In other words, to be approved, it should work just as well as the reference product. That means that it has to be just as safe and just as effective as the original. Biosimilars are developed by competing medical technology companies who hope they can make money by selling an effective but less expensive version of an originally approved treatment once it comes off patent.

In order to be approved by the FDA, bisiomilar treatments must undergo scientific studies to demonstrate that they have no clinically meaningful difference from the original biologic product.

Are Biosimilars The Same as Generic Medications?

No, not exactly, although they have some things in common. 

Generic medications are a type of traditional pharmaceutical drug. They have the same active ingredient as the original drug. For example, “acetaminophen” is an over-the-counter pain medication, the active ingredient in Tylenol and in generically produced products (e.g., by Walgreens or another pharmacy). Generics have identical active ingredients to the brand name product (although there might be differences in inactive ingredients like fillers, dyes, etc). Generics also have the same dosage, route of administration, strength, and safety as the original product, and they are intended to be used the same way. Another word for this is that they are bioequivalent.

In contrast, biosimilar products cannot be chemically identical in this same way. That’s because these treatments are too complex, requiring cells, animals, or complex biological systems. There is inherent variability in living molecules and thus in biologic therapies. Even between different batches of the same biologic treatment, there are going to be natural variations. Just small changes in the process of production can cause some variations in the final biologic product. So the active part of the biosimilar cannot be shown to be identical to the original biologic in the same way that the active ingredient in a generic medication is identical to the original medication.

However, similar to generics, biosimilars should have no clinically meaningful differences compared to the original biologic product. Like generics, biosimilars can also undergo shortened forms of testing by the FDA, avoiding some of the costly clinical trials required for approval of the original product. And, like generics, they are often less expensive than the original products.

What Is the Advantage of Using Biosimilars?

The main advantage to health consumers is reduced cost. Biosimilars potentially offer consumers the opportunity to reduce their health care costs without compromising on treatment standards. They also may reduce health care savings in the system as a whole.

Although they have been very effective in treating certain medical conditions, many biologics are expensive. One estimate calculated that biologic treatments accounted for 38% of prescription drug spending in the US in 2015, due to the high expense per dose. Researchers predict the move to biosimilars could save the health care system billions of dollars over the next several years.

Often, a biosimilar will have a lower out-of-pocket cost compared to a biologic. But your particular savings may vary, depending on your insurance coverage. 

What Biologic Treatments Have Biosimilars Available? 

As of June 2019, the FDA has approved over 20 different biosimilar products. The following reference biologic products have one or more FDA approved biosimilars:

  • Trastuzumab
  • Infliximab
  • Adalimumab
  • Pegfilgrastim
  • Filgrastim
  • Rituximab
  • Epoetin alpha
  • Bevacizumab
  • Etanercept

These biosimilars can be used to treat a number of different health conditions, including cancer and autoimmune conditions. An example from cancer treatment is Truxima (biosimilar to rituximab) for non-Hogskins lymphoma. Similarly, Ogivri (biosimilar to trastuzumab) is used for certain breast and stomach cancers.

Certain biosimilars may be used to treat a number of different health conditions. For example, the biosimilar to the biologic medication adalimumab is approved to treat a number of different kinds of arthritis, including rheumatoid arthritis and ankylosing spondylitis, as well as psoriasis and inflammatory bowel disease.

For certain health conditions, such as rheumatoid arthritis, more than one biosimilar treatment may be available. In other cases, a physician might prescribe a biosimilar off-label, if there is good reason to suspect that a treatment might be effective, even if it hasn’t undergone studies necessary for FDA approval. 

More biosimilar treatments are currently being developed. Many more may become available in the next several years. If you aren’t sure if a biosimilar is available for your particular condition, don't hesitate to bring it up with your health care provider.

How Are Biosimilars Named?

It’s easy to get confused about the naming of these products. For example, “Eticovo” is an FDA approved biosimilar to the biologic treatment etanercept. Eticovo is also known as “etanercept-ykro.” The trade name for etanercept (the original biologic drug) is “Enbrel,” so that can be confusing as well. 

Other biosimilars have names like this, in which the biologic treatment being referenced is found in the first part of the word, followed by a suffix of four letters. In some cases, there may be more than one biosimilar available for a specific biologic product. Keep track of the exact product you are using so you can communicate about it clearly with all your health care providers.

Are Biosimilars as Effective as the Original Biologic Product? 

Some clinicians and patients have expressed concerns that biosimilar treatments might not be as safe as effective as the original biologics. Because these are newer treatments, many clinicians did not study them as part of their initial training. Some have lacked familiarity and understanding of the differences between biosimilars and original biologic treatments. Hence not as many clinicians have prescribed biosimilars as might have otherwise. However, this might change as more health care providers get comfortable with these products.

The main thing to remember is that in order to be FDA approved, a biosimilar must have been shown to have no clinically meaningful differences. That means they should be just as effective and just as safe. One recent paper analyzed data from 90 different studies which compared health outcomes in people receiving a biosimilar or an original biologic product. The large majority of these studies did not detect any differences in effectiveness or safety. This should help reassure health professionals and patients about biosimilars. However, it is also important to note that biosimilars can sometimes have significant side effects, just as the original biologic products can.

Some patient groups have put out statements about biosimilars in an effort to advocate for patients’ needs. For example, you can read the statement of the National Psoriasis Foundation Medical Board. Some physician societies, such as the American Gastroenterological Association, have put out information to their members about the value of biosimilar products, such as for inflammatory bowel disease.

If you have concerns about the safety or effectiveness of a particular biosimilar, don’t hesitate to discuss them with your clinician. There might be specific data that you can discuss about your particular biosimilar treatment. On the other hand, if you know a biosimilar is available for your treatment, you may want to bring up the possibility of switching. Your physician may simply not have had a lot of experience prescribing biosimilars.

Can My Pharmacist Substitute a Biosimilar for My Biologic Without Asking?

No, not currently. This contrasts with non-biologic treatments, in which your pharmacist may automatically replace a trade named product with a generic product, if one is available, unless your doctor has specified otherwise. In other words, you will never receive a biosimilar product at the pharmacy unless your healthcare provider specifically prescribed it. It’s possible that this might change at some point, if the FDA changes its regulations on specific biosimilars, and if particular drugs are deemed “interchangeable” with the original biologic product.

The flip side is that you might not even know if a less expensive biosimilar product is commercially available unless your healthcare provider brings it to your attention. Your pharmacist may also know if a biosimilar product is on the market. Don’t hesitate to ask if you aren’t sure. That way, you can explore all your options.

Was this page helpful?

Article Sources

  1. de Mora F. Biosimilar: what it is not. Br J Clin Pharmacol. 2015;80(5):949–956. doi:10.1111/bcp.12656

  2. Williamson C, Berger L, Sullivan TP, et al. Addressing oncologists' gaps in the use of biosimilar products. Am J Manag Care. 2019;25(6 Spec No.):SP188-SP191.


  3. Ferro A, Boyce M. Biological therapies: a long way on from Jenner. Br J Clin Pharmacol. 2013;76(2):161-3. doi:10.1111/bcp.12202

  4. US Food and Drug Administration. Biosimilar and interchangeable products. Current as of October 23, 2017.

  5. Dunne S, Shannon B, Dunne C, et al. A review of the differences and similarities between generic drugs and their originator counterparts, including economic benefits associated with usage of generic medicines, using Ireland as a case study. BMC Pharmacol Toxicol. 2013;14:1. doi:10.1186/2050-6511-14-1

  6. Reinke T. Why biosimilars can never be identical to originators--and why they

    don't need to be. Manag Care. 2019 Jan;28(1):10-11. 

  7. Mulcahy AW, Hlavka JP, Case SR. Biosimilar cost savings in the United States: initial experience and future potential. Rand Health Q. 2018;7(4):3. 

  8. US Food and Drug Administration. Biosimilar product Information. Current as of July 20, 2018.

  9. US Food and Drug Administration. FDA approves Amjevita, a biosimilar to Humira. September 23, 2016.

  10. Leonard E, Wascovich M, Oskouei S, et al. Factors affecting health care provider knowledge and acceptance of biosimilar medicines: a systematic review. J Manag Care Spec Pharm. 2019;25(1):102-112. doi:10.18553/jmcp.2019.25.1.102

  11. Cohen HP, Blauvelt A, Rifkin RM, et al. Switching reference medicines to biosimilars: a systematic literature review of clinical outcomes. Drugs. 2018;78(4):463–478. doi:10.1007/s40265-018-0881-y

  12. American Gastroenterological Association. Biosimilars.