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Managing Cancer Care

Biosimilar Drug Safety

A biosimilar drug is a type of biologic drug — a medicine made from a biological or natural source. A biosimilar drug is a safe and effective, high-quality treatment that is "highly similar with no meaningful clinical differences" to a brand name biologic drug that's used to treat a certain disease.

Are biosimilar drugs safe?

There are strict rules about how a biosimilar drug is tested for its safety, and what that testing needs to show. Just like any drug, a biosimilar drug is tested in clinical trials to make sure it is safe to use in people. The data from the clinical trials are carefully reviewed by the Food and Drug Administration (FDA) to be sure the biosimilar drug is just as safe and effective as its brand name biologic drug. If a biosimilar drug is approved by the FDA, this means it has met the strict standards for being safe. Learn more about how a biosimilar drug is tested in What Are Biosimilar Drugs?

After a drug gets FDA approval to treat a certain type of cancer and is "on the market," doctors can start using it. Doctors and other members of the cancer care team often give the FDA feedback about how they're using drugs to treat people with cancer. This data is called post-marketing information. This information helps the drug companies and the FDA make sure drugs are still safe, meaning they are doing what they're supposed to do and aren't causing more side effects than what clinical trials showed. Just like for other drugs used to treat cancer, post-marketing information is collected for biosimilar drugs.

Are special precautions needed for biosimilar drugs?

Much is known about the need to protect others from exposure to chemotherapy (chemo) because it can be dangerous. This is why there are safety rules and recommendations for people who handle chemo drugs. However, because biologic (and biosimilar) drugs are newer, there is not as much information about long-term effects of exposure. To be safe, many experts recommend treating biologic drugs, including biosimilars, as hazardous and taking the same precautions as when handling chemotherapy. This is especially true because many biologic drugs are given along with other drugs that are known to be hazardous, so your cancer care team will take precautions to protect themselves and others from exposure to them. You can read more in Targeted Therapy Safety.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

De Mora F. Biosimilar: what it is not. British Journal of Clinical Pharmacology. 2015;80(5):949-956.

Lyman GH, et al. American Society of Clinical Oncology statement: Biosimilars in oncology. Journal of Clinical Oncology. 2018;36(12):1260-1266.

US Food and Drug Administration. Biosimilars. 2020. Accessed at on March 3, 2020.

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: March 9, 2020

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