What is a Biologic? 

A biologic is a medicine that is made from a live organism that can be used to treat illnesses, including cancer. Examples of biologics include medications such as Humira (adalimumab), Remicade (infliximab), and Rituxan (rituximab).

This is different from traditional medicines, which are made from chemicals. For cancer, biologics can be used to directly destroy cancer cells and or to trigger the immune system to work against the cancer. 

These medicines are very complex, and it can take a long time for them to be discovered, developed, and reviewed. Due to this process, biologic drugs tend to be very expensive.   

What is a Biosimilar? 

A biosimilar is a medicine that is highly similar to its originating, or interchangeable, biologic medicine, and used to treat the same diseases. Biosimilars are created by utilizing some of the knowledge gained by the biologic’s production, for a shortened development and approval time. This makes them much less expensive.

The Food and Drug Administration (FDA) rigorously reviews and evaluates biosimilars to ensure they are “highly similar” to the original biologic. Through this process, the biosimilar must prove to be as effective and as safe as the biologic; it also must be given in the same way, and have the same dose and strength. Commonly known biosimilars for the drug Avastin (bevacizumab) include Mvasi, Zirabev, and Alymsys.  

The process of developing a biosimilar is legal only after the patent on the original biologic has expired 20 years after it is approved.  

Biosimilar vs. Generic Equivalent   

A common misconception is that biologics and biosimilars have the same relationship as brand and generic medicines. Branded drugs and generic medicines are chemically identical, whereas biosimilars can have structural differences from biologics. 

Using a Biosimilar vs. a Biologic

Biosimilars are typically used instead of the related biologic because they are cheaper for patients than the originating biologic.   

Risks to Using a Biosimilar Instead of a Biologic 

In order to be approved for use by the FDA, there must be no meaningful clinical differences between a biosimilar and its originator biologic. Due to rigorous process for review and approval, and the high standards of the FDA, patients should be confident that this medicine is as safe and as effective as its interchangeable biologic.  

The American Cancer Society maintains a list of some more common biosimilars being used in cancer treatment.