Biosimilar Medicines
Biosimilars are more affordable alternatives to a specific class of medicines called biologics, including some immunotherapies used to treat many types of cancer. While they are not exact copies, biosimilars follow strict FDA guidelines to ensure they work the same and are just as safe as brand name biologic medicines.
What is a biosimilar?
A biosimilar, or biosimilar medicine, is a medicine that is very close in structure and function to an existing brand name biologic medicine. The original biologic medicine is known as the reference product and has already been approved for use in the United States.
A biosimilar behaves in much the same way as its brand name biologic, so there are “no meaningful differences" between how the two medicines work. This means that the biosimilar is considered as safe and effective as the biologic reference product.
According to the FDA, when compared to their brand name biologic (reference product), a biosimilar:
- Is made with the same types of natural sources
- Is given the same way
- Provides the same treatment benefits
- Has the same potential side effects
- Has the same strength and dosage
What is a biologic?
A biologic, or biologic medicine, is a complex medicine made from a living source or organism, such as yeast, bacteria, or animal cells. Biologic medicines have become part of the standard of care to treat some cancers and other diseases.
Examples of biologics used in cancer treatment include immunotherapy and some targeted therapies. They can work in many ways. For example, they might:
- Help the body’s immune system recognize and kill cancer cells more effectively
- Work against certain proteins in or on cancer cells to stop their growth
- Help the body make more blood cells to replace ones lost because of other cancer treatments
Biologics are different from drugs, which tend to be simpler chemicals that can be made the same way each time. But just like drugs, biologics need to be approved by the US Food and Drug Administration (FDA) before they can be sold.
Are biosimilars the same as generic drugs?
A biosimilar is a little like a generic drug version of a biologic, but there are some differences. A generic drug is an exact copy of a brand name drug. They have the same chemical makeup.
But biologic medicines come from natural, living sources. They can’t be copied exactly because natural sources are very complex and their environments can change. So, while a biosimilar is highly similar to its brand name biologic medicine, it’s not an exact copy of it.
Are biologics and biosimilars interchangeable?
Medicines that are interchangeable are considered equal substitutes. For example, if your doctor writes you a prescription for a brand name drug, the pharmacy might fill it with a less expensive generic version unless the doctor requests otherwise.
Not all biosimilars are considered interchangeable with their brand name biologic. After a biosimilar is approved for use by the FDA, it must go through more testing before it is considered interchangeable.
- If the biosimilar is approved as interchangeable, the pharmacy might fill a prescription for the brand name biologic with the biosimilar, which is likely to be less expensive.
- If a biosimilar is not approved as interchangeable and your doctor wants you to get it, they need to write the prescription specifically for the biosimilar.
Are biosimilars safe?
Yes. Like all medicines sold in the US, biosimilars need to be tested and approved by the FDA before they can be used to treat a disease.
Because biosimilars aren’t exact copies of biologics, they go through more testing than generic drugs. Each biosimilar is tested in clinical trials, comparing it to the original biologic. The FDA reviews the results to make sure the biosimilars are just as safe and effective as their brand name medicines.
FDA approval means a biosimilar has met strict safety standards. Testing must show that both the biosimilar and the brand-name biologic:
- Are made from the same source
- Have the same dose and strength
- Are given the same way (for example, by mouth)
- Have the same benefits in treating a disease
- Have the same possible side effects
Are biosimilars cheaper?
Yes, biosimilars are generally much cheaper than brand-name biologics. Like generic drugs, their main purpose is to offer a lower-cost alternative to brand name medicines.
Brand name biologics often cost a lot because they’re difficult to study and make. But their high price can make it hard for people to access treatments they need. To help make biologics more affordable, the federal government passed the Biologics Price Competition and Innovation Act (BPCIA). This law created a faster approval process for biosimilars through the FDA.
Biosimilars typically cost 10% to 50% less than their brand name biologics. Insurance companies often cover biosimilars just as they do the brand name biologic, but not always. If you’re considering a biosimilar, check with your insurance company about coverage first.
Some experts have estimated that biosimilars could save many billions of dollars in health care costs over the course of many years. But this will depend on how many biosimilars become available, what diseases they can treat, and how widely they’re used.
Examples of biosimilars used in cancer treatment
There are many biologic medicines being used to treat cancer, and some now have biosimilar versions available. Some biosimilars have been approved to treat certain types of cancer, and some have been approved to help manage side effects. You can search for a specific cancer to learn more about how it is treated in Cancer Types.
Biosimilars for the biologic medicine bevacizumab (Avastin):
- Mvasi
- Zirabev
- Alymsys
- Vegzelma
- Avzivi
- Jobevne
Biosimilars for the biologic medicine rituximab (Rituxan):
- Truxima
- Ruxience
- Riabni
Biosimilars for the biologic medicine trastuzumab (Herceptin):
- Ogivri
- Herzuma
- Ontruzant
- Trazimera
- Kanjinti
- Hercessi
Biosimilars for the biologic medicine filgrastim (Neupogen):
- Zarxio
- Nivestym
- Releuko
- Nypozi
Biosimilars for the biologic medicine pegfilgrastim (Neulasta):
- Fulphila
- Udenyca
- Ziextenzo
- Nyvepria
- Fylnetra
- Stimufend
Biosimilar for the biologic medicine epoetin alfa (Epogen or Procrit):
- Retacrit
Biosimilars for the biologic medicine denosumab (Xgeva):
- Wyost
- Xbryk
- Osenvelt
- Bomyntra
- Written by
- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Association for Accessible Medicines (AAM). 2024 U.S. Generic & Biosimilar Medicines Savings Report. 2024. Accessed at https://accessiblemeds.org/wp-content/uploads/2024/09/AAM-2024-Generic-Biosimilar-Medicines-Savings-Report-Fact-Sheet.pdf on March 26, 2025.
Cauchi R. State Laws and Legislation Related to Biologic Medications and Substitution of Biosimilars. As of January 26, 2021: https://www.ncsl.org/research/health/state-laws-and-legislation-related-tobiologic-medications-and-substitution-of-biosimilars.aspx
Ferrario A, Dedet G, Humbert T, Vogler S, Suleman F, Pedersen HB. Strategies to achieve fairer prices for generic and biosimilar medicines. The BMJ. 2020;368:15444.
Nahleh Z et al. Use of biosimilar medications in oncology. JCO. 2022;18:3. Available at https://ascopubs.org/doi/full/10.1200/OP.21.00771
National Comprehensive Cancer Network (NCCN). White Paper: Safe & Efficient Use of Biosimilars. 2021. Accessed at https://www.nccn.org/docs/default-source/default-document-library/2021_nccn_white_paper_safe_and_efficient_use_of_biosimilars.pdf on March 26, 2025.
PhRMA. Biologics & Biosimilars. 2023. Accessed at https://phrma.org/biologics-biosimilars on March 26, 2025.
Rodriguez G et al. ASCO Policy Statement on Biosimilar and Interchangeable Products in Oncology. JCO. 2023;19:7. Available at https://ascopubs.org/doi/10.1200/OP.22.00783
Stebbing J, et al. Understanding the role of comparative clinical studies in the development of oncology biosimilars. JCO. 2020;38 [epub ahead of print].
US Food and Drug Administration. Biosimilars. 2023. Accessed at https://www.fda.gov/drugs/therapeutic-biologics-applications-bla/biosimilars on March 26, 2025.
US Food and Drug Administration. Biosimilar Product Information. 2025. Accessed at https://www.fda.gov/drugs/biosimilars/biosimilar-product-information on March 26, 2025.
US Food and Drug Administration. Biosimilars Basics for Patients. 2024. Accessed at https://www.fda.gov/drugs/biosimilars/biosimilars-basics-patients on March 26, 2025.
Zand JM. Patient education: Coping with high prescription drug prices in the United States (Beyond the Basics). UpToDate. 2024. Accessed at https://www.uptodate.com/contents/coping-with-high-prescription-drug-prices-in-the-united-states-beyond-the-basics on March 26, 2025.
Zelenetz A, et al. National Comprehensive Cancer Network biosimilars white paper: Regulatory, scientific, and patient safety perspectives. Journal of the National Comprehensive Cancer Network. 2011;9(S4).
Last Revised: April 14, 2025
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