(T0930-06-31) Assessing the Analytical Similarity of the Biosimilar Candidate ABP 654 to Ustekinumab Reference Product

Purpose: ABP 654 is a proposed biosimilar to ustekinumab reference product (RP), a human immunoglobulin isotype class G subclass 1 kappa monoclonal antibody that is a therapeutic antagonist of interleukin (IL)-12 and IL-23. Binding of ustekinumab to the common p40 subunit of the IL‑12 and IL‑23 cytokines prevents interaction with their cognate receptors, resulting in the inhibition of downstream signalling that leads to immune modulation.¹ Ustekinumab RP is indicated for the treatment of some forms of plaque psoriasis, active psoriatic arthritis, Crohn’s disease, and ulcerative colitis.² The purpose of this study was to assess analytical similarity between ABP 654 and ustekinumab RP sourced from the United States (US) and European Union (EU).

Methods: Comprehensive analytical assessment incorporating orthogonal analytical techniques was used to compare ABP 654 and ustekinumab RP sourced from the US and EU. Reduced peptide map analysis was used to assess amino acid sequence, disulfide linkage patterns, and primary structure characteristics. Fourier transform infrared spectroscopy, ultraviolet circular dichroism spectroscopy, and differential scanning calorimetry were employed to evaluate secondary and tertiary structures of ABP 654 and ustekinumab RP. The N-linked glycosylation in ABP 654 and ustekinumab RP was determined by glycan map. Physicochemical properties of size and charge variants were assessed using a combination of methods, including size-exclusion ultra-high-performance liquid chromatography, cation exchange high-performance liquid chromatography, and reduced and non-reduced capillary electrophoresis-sodium dodecyl sulfate. The functional similarity assessment was designed to evaluate all expected biological activities mediated by the Fab and Fc regions of the molecule, including those known to affect the mechanisms of action (MOA) for ustekinumab RP, and to evaluate the biological impact of any subtle structure differences.

Results: ABP 654 is expressed in a glyco‑engineered Chinese hamster ovary (CHO) cell line, whereas ustekinumab RP is expressed in a murine myeloma (SP2/0) cell line. ABP 654 had the same amino acid sequence and a similar post-translational modification profile compared with ustekinumab RP sourced from the US and EU. Primary structure, higher-order structure, and biological activities were similar for the three products. Product-related size and charge variants and aggregate and particle levels were also similar. The finished ABP 654 drug product has the same strength with regard to protein concentration and fill volume as ustekinumab RP. Expected minor and well‑understood structural differences have been observed between ABP 654 and ustekinumab RP due to their production in different cell expression systems.

Conclusion: Based on a comprehensive similarity assessment, ABP 654 was found to be analytically similar to ustekinumab RP (both US and EU) with respect to physicochemical and biological properties. The observed minor structural differences are not expected to impact clinical safety or efficacy because the biological activities of ABP 654 and ustekinumab RP relevant to the MOA are similar.

References: 1. Teng MW, Bowman EP, McElwee JJ, et al. Nat Med. 2015;21(7):719-729.
2. STELARA® (ustekinumab). United States Prescribing Information. Horsham, PA: Janssen Biotech, Inc. December 2020.

Acknowledgements: Medical writing assistance was provided by Alex Romero, PhD (Amgen Inc.), under the direction of Sonya Lehto, PhD (Amgen Inc.).

Funding: This study was funded by Amgen Inc., Thousand Oaks, CA.
Conflict of Interest: Greg Cantin, Bin Lu, and Jennifer Liu are employees and stockholders of Amgen Inc.