Characterization for the Similarity Assessment Between the Proposed Biosimilar SB17 and Ustekinumab Reference Product Using State-of-the-Art Analytical Methods.

Abstract

Background: SB17 is being developed as a biosimilar to ustekinumab reference product (RP), a human monoclonal antibody (IgG1 kappa immunoglobulin) that binds to the common p40 subunit of cytokines interleukin (IL)-23 and IL-12. Binding to this subunit prevents interaction with their receptor, resulting in modulation in the immune system responses that play a key role in inflammatory disease.

Objective: The objective of this study was to demonstrate structural, physicochemical, and biological similarity between ustekinumab RP and SB17 using various state-of-the-art analytical methods.

Methods: Comprehensive analytical characterization was conducted by the quality range and side-by-side comparison approach for SB17 versus the European Union (EU) and US ustekinumab RP using various analytical methods. Comparisons included purity, product-related impurity, charge heterogeneity, primary structure, posttranslational modification, higher-order structure, quantity, Fab-related biological activities (potency and binding activity), and Fc-related biological activities.

Results: On the basis of the analytical similarity assessment, the structural, physicochemical, and biological characterization results demonstrated that SB17 is comparable to the ustekinumab RP. In the structural aspects, it was confirmed that there is no clinically meaningful difference between posttranslational modification profiles and higher-order structures of SB17 compared with the ustekinumab RP. Product-related impurities in the form of aggregates were also confirmed to be similar. SB17 has lower acidic and basic variants compared with ustekinumab RP, owing to the difference in the producing cell line. Ustekinumab RP is expressed in an Sp2/0 cell line, whereas SB17 is expressed in CHO cell line. However, the difference between SB17 and ustekinumab RP in the charge variants is not considered to be clinically meaningful, since equivalent biological activity was observed. In the case of mechanism of action (MoA)-related biological activities, SB17 is highly similar to the EU and US ustekinumab RP with respect to overall critical and noncritical quality attributes analyzed. Moreover, similarity or lack of activity in Fc-related biological activities was also confirmed. On the basis of these results, SB17 is expected to have comparable safety and efficacy as compared with ustekinumab RP.

Conclusion: In summary, the overall analytical characterization and similarity assessment results show that SB17 is comparable to the EU and US ustekinumab RP in terms of structural, physicochemical, biophysical, and biological attributes.