Abstract: Based on the principle of progressive comprehensive comparability, must be similar to reference drugs in terms of physicochemical properties, bioactivity, pharmacokinetics, efficacy, and safety (including immunogenicity). The objective of the immunogenicity assessment of biosimilars is to assess potential differences in the incidence and severity of human immune responses between biosimilars and reference drugs. No clinically significant differences in immune responses between the two products is a key factor in demonstrating biosimilarity. The influencing factors include subjects, sampling scheme, product factors and bioanalysis methods. An important issue in bioanalysis is the selection of two-assay (based on biosimilars and reference agents respectively) or one-assay (based on biosimilars respectively) as the best method for comparative immunogenicity assessment. In order to support the development of biosimilars, this paper focuses on the use of One-assay to evaluate immunogenicity based on biosimilars. The development and validation of an ADA assay for biosimilar drugs should include all validation of the original drug. In addition, biosimilars need to be compared with reference to confirmation thresholds, antigenic equivalence, and drug tolerance to assess the ability of biosimilars and reference drugs to bind in a similar manner to positive controls. ADA data analysis should be combined with PK/PD parameters and clinical events.

Key words: biosimilars, immunogenicity, bioanalysis, one-assay