Dear Addy: Biosimilars
Dear Addy,
I keep hearing about biosimilars. What are they, and how do they differ from generic drugs?
Curious About Products

Hi Curious,
Thanks for your question. A biosimilar is a pharmaceutical drug that is made to have similar active properties as a biological drug that has already been licensed. Biologics are really important to our community because almost all of the products that people with bleeding disorders take are biologics. In order to understand why biosimilars are important to our community, you must first know the difference between a chemical drug and a biologic. Chemical drugs are first made by synthesizing chemicals together. Their molecules are very uniform, and simple. Generic drugs are made by recreating these molecules exactly. Therefore, a generic version of a chemical drug will have the exact same molecular structure as the original drug.
Biologics, however, are much more difficult to produce. They are made within living cells, such as an animal or plant cell. Their molecules are much more complex, as a result. When a biosimilar is made, it is made using a reference biologic. The processes for making biologics are very complex, and things like a slight variation in temperature can affect how they’re made. Therefore, though a biosimilar is based on a reference product, it will look different.
To get an idea of how a biosimilar varies from its reference biologic, please watch the above video. Though they are similar, they are not the same.
Biosimilars might also be produced from different cell lines than biologics, making it even more impossible for them to be the exact same as their biological counterparts. Because biosimilars can never be the same as their biologic counterparts, it is important for patient safety that the rules for biosimilars be different than chemical drugs.
You can learn what HFA is doing to advocate for biosimilars and product safety here. If you have any more questions, please feel free to write to me using the link below.
Have a question? Click HERE. Your name will be changed in the response.

HFA frequently receives questions from the bleeding disorders community related to advocacy issues. The questions often impact the entire community. In an effort to reach the largest audience possible with our responses to these widely applicable questions, HFA developed “Dear Addy.” Questions submitted to this column are edited in order to protect privacy and should be considered educational only, not individual guidance.