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Biosimilars in Cancer Care: What Patients Need to Know
A patient-friendly guide to understanding biosimilars, biologics, and why your cancer treatment may be switched.
A Patient May Ask:
“Is a biosimilar drug the same as a generic?”
The short answer is no. Biosimilars and generic drugs are not the same, although both may be used as more affordable alternatives to original brand-name medications.
A generic drug is an exact copy of a simple chemical medication. A biosimilar is a highly similar version of a biologic medication. Biologic drugs are made from living cells and are much more complex than traditional medications, so they cannot be copied in exactly the same way.
What Is a Biologic?
Biologic medications are treatments made using living systems, such as cells or proteins. In oncology, biologics may include medications such as monoclonal antibodies and growth factors.
Examples of biologic medications used in cancer care may include:
- Trastuzumab
- Rituximab
- Bevacizumab
- Filgrastim
- Pegfilgrastim
What Is a Biosimilar?
A biosimilar is a biologic medication that is highly similar to an original biologic drug, sometimes called the “reference biologic” or “originator” drug.
Because biologics are complex and made from living systems, a biosimilar is not an exact copy. However, approved biosimilars must demonstrate that there are no clinically meaningful differences in safety and effectiveness compared with the original biologic.
How Are Biosimilars Approved in Canada?
In Canada, biosimilars are reviewed and approved by Health Canada. Before a biosimilar can be used, it must meet strict standards for quality, safety, and effectiveness.
Health Canada reviews evidence showing that the biosimilar is highly similar to the reference biologic and that it is expected to work in the same way.
Why Might My Cancer Centre Switch Me to a Biosimilar?
Biosimilars are often less expensive than the original biologic medication. This does not mean they are lower quality or less effective.
Lower medication costs can help support access to cancer treatments and help healthcare systems use resources more sustainably. In publicly funded healthcare systems, such as Canada’s, this can be an important part of maintaining access to high-quality care.
Myths vs Facts About Biosimilars
Myth
Biosimilars are just generic drugs.
Fact
Biosimilars are not the same as generic drugs. Generics are exact copies of simpler medications. Biosimilars are highly similar versions of complex biologic drugs.
Myth
Biosimilars are less effective because they cost less.
Fact
Lower cost does not mean lower quality. Biosimilars approved in Canada must meet rigorous standards for safety, effectiveness, and quality.
Myth
If I am switched, my treatment may stop working.
Fact
Approved biosimilars are expected to provide comparable safety and effectiveness to the original biologic. Your oncology team will continue to monitor your response and side effects.
Questions to Ask Your Oncology Team
- Am I receiving a biosimilar or the original biologic?
- Why is this medication being recommended or switched?
- What side effects should I watch for?
- How will we know if the treatment is working?
- Who should I contact if I have concerns after treatment?
The Bottom Line
Biosimilars are not “weaker” or “lower-quality” cancer treatments. They are carefully reviewed medications that must meet Canadian standards for safety, effectiveness, and quality.
If you are told your treatment is changing to a biosimilar, it is reasonable to ask questions. Understanding why the change is being made can help you feel more confident and prepared.
How Present Help Can Support You
At Present Help, we help patients and families better understand cancer treatment information, prepare questions for oncology appointments, and feel more confident navigating care between clinic visits.
Disclaimer: This blog is for general education only and does not replace medical advice from your oncology team. Always speak with your cancer care team before making decisions about treatment.
Sources: Health Canada; Ontario Health / Cancer Care Ontario biosimilars patient information.
AI assistance note: This article was written with the assistance of artificial intelligence and reviewed for clarity, patient education, and relevance to oncology supportive care.
June Ng-A-Kein
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