Characteristics of biosimilars

What is a biosimilar?

A biosimilar product is a biologic product that is approved based on demonstrating that it is highly similar to an FDA‐approved biologic product, known as a reference product, and has no clinically meaningful differences in terms of safety and effectiveness from the reference product. Only minor differences in clinically inactive components are allowable in biosimilar products.

How are biosimilars different from generic medicines?

While identical generic versions of small molecules can be chemically synthesized, it is not possible to create identical versions of reference biologic medicines, due to their complexity. Therefore, the processes used to develop generic medicines cannot be applied to the development of biosimilar medicines.

The complexity of biologics

Biosimilars (and reference biologics) are created in living cells and require significant expertise and state-of-the-art technology in development and manufacturing.
Comparing biologic medicines, including biosimilars,
to small-molecule drugs




  • Small-molecule drugs are smaller and less complex than biologics and are chemically synthesized
  • Conversely, biologics are larger and more complex and are created from living cells