Table 2.

Terms and Definitions²⁷

Term	Definition
Biologic	A medicinal product derived from a variety of natural sources Includes large, protein-based therapeutic agents derived from living cell lines using recombinant DNA technology such as hormones and monoclonal antibodies
Biosimilar	A biologic product that is approved based on showing that it is highly similar to an FDA-approved biologic product (originator product) and has no clinically meaningful differences in terms of safety and effectiveness from the originator product. Only minor differences in clinically inactive components are allowable.
Interchangeable	A biosimilar to an FDA-approved originator product that meets additional standards for interchangeability. An interchangeable biosimilar may be substituted for the originator product by a pharmacist without the intervention of the health care provider who prescribed the originator product. An interchangeable biosimilar is expected to produce the same clinical result as the originator biologic agent in any given patient.
Extrapolation	Clinical studies of biosimilars can be performed in a disease state or sensitive population group and then inferred to work in other disease settings or indications for which the originator biologic product is approved and licensed, with sufficient scientific justification.

FDA, US Food and Drug Administration.