Abstract
Biologic agents are macromolecules, and as such, they have a high level of structural heterogeneity. Treatment with such agents has been extremely expensive limiting thus their availability to increasing numbers of patients; therefore, many manufacturers chose to develop biologics that are highly similar to the originators, the biosimilars. The immunological properties of both products should therefore be characterized and compared. The biosimilar developers must have a complete qualitative documentation, appropriate preclinical pharmacodynamic and pharmacokinetic studies, and finally comparative studies with the originator to define the relative similarity in terms of biologic activity, quality characteristics, efficacy and safety. Immunogenicity assessment of the biosimilars continues through clinical trials and pharmacovigilance programs.