What is a biosimilar?

In a previous blog we spoke about what a biologic medication is, and how it is produced through the programming of live cells to produce a treatment that mimics a protein structure in a human. Biosimilars are produced after the originator biologic’s patent has expired. The living cells used to produce the biosimilar will be different than the originator biologic and therefore the final product can never be called identical, but can be considered highly similar.

Health Canada requires testing in humans to ensure the biosimilar will be as effective and safe as the original biologic. We now have two biosimilars for the medication Remicade (infliximab): Inflectra and Renflexis.. There are also two biosimilars for the medication Enbrel (etanercept):Brenzys and Erelzi. There are many more on the horizon.

The cost of biosimilars is significantly less than the originator biologic and therefore many government and private insurance plans are requesting a biosimilar be used when a person is first starting this type of treatment. Many Canadians are currently using biosimilars with great success.

As a cost saving measure, there are now insurance plans requesting patients who are on a biologic and doing well, switch to the biosimilar (if one exists for the biologic they are taking). There are many studies that have been done assessing switching from the originator biologic to a biosimilar. In most trials, patients experienced no changes. There are however situations where the switch resulted in greater improvement in a person’s disease and others where the person’s condition worsened. As we gain more experience with biosimilars, it will be important to track each manufacturer’s biosimilar to monitor any changes in effectiveness and adverse effects. There are no studies regarding switching between different biosimilars.


Carolyn Whiskin is the Pharmacy Manager for Charlton Health.  Carolyn specializes in the treatment of autoimmune diseases, pharmaceutical compounding, women’s health, pain and smoking cessation. Carolyn has won provincial and national awards for her commitment to patient care and public service.

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