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Background: Adalimumab-aqvh/CHS-1420 (YUSIMRY TM ) (hereafter referred to as adalimumab-aqvh) was recently approved by the US Food and Drug Administration as a biosimilar for adalimumab., Objective: The current study was conducted to investigate the analytical similarity of adalimumab-aqvh and the reference product, adalimumab., Methods: The structural, functional, and stability attributes of adalimumab-aqvh and adalimumab were compared using state-of-the-art assays. The primary structure, disulfide structure, glycan profile, secondary and tertiary structures, molar mass, size variants, free thiol, charge variants, hydrophobic variants, post-translational modifications, subvisible particles, host cell proteins, and protein concentration were investigated. The functional similarity between adalimumab-aqvh and adalimumab was demonstrated by comparing fragment antigen-binding (Fab)-associated and fragment crystallizable (Fc)-associated biological activities. The stability of adalimumab-aqvh and of adalimumab was compared through forced degradation., Results: The structural attributes of adalimumab-aqvh were identical to those of adalimumab or met the similarity criteria, with a few exceptions. Adalimumab-aqvh and adalimumab exhibited comparable stability profiles and functional activities. Any observed differences in the physiochemical attributes did not impact the conclusion of similarity because they did not influence any functional activities related to the adalimumab mechanism of action., Conclusion: The structural, functional, and stability data provide convincing evidence of biosimilarity between adalimumab-aqvh and the reference product, adalimumab., (© 2023. The Author(s).)

To explore the variability in biosensor studies, 150 participants from 20 countries were given the same protein samples and asked to determine kinetic rate constants for the interaction. We chose a protein system that was amenable to analysis using different biosensor platforms as well as by users of different expertise levels. The two proteins (a 50-kDa Fab and a 60-kDa glutathione S-transferase [GST] antigen) form a relatively high-affinity complex, so participants needed to optimize several experimental parameters, including ligand immobilization and regeneration conditions as well as analyte concentrations and injection/dissociation times. Although most participants collected binding responses that could be fit to yield kinetic parameters, the quality of a few data sets could have been improved by optimizing the assay design. Once these outliers were removed, the average reported affinity across the remaining panel of participants was 620 pM with a standard deviation of 980 pM. These results demonstrate that when this biosensor assay was designed and executed appropriately, the reported rate constants were consistent, and independent of which protein was immobilized and which biosensor was used.

To explore the reliability of Biacore-based assays, 22 study participants measured the binding of prostate-specific antigen (PSA) to a monoclonal antibody (mAb). Each participant was provided with the same reagents and a detailed experimental protocol. The mAb was immobilized on the sensor chip at three different densities and a two-step assay was used to determine the kinetic and affinity parameters of the PSA/mAb complex. First, PSA was tested over a concentration range of 2.5-600 nM to obtain k(a) information. Second, to define the k(d) of this stable antigen/antibody complex accurately, the highest PSA concentration was retested with the dissociation phase of each binding cycle monitored for 1h. All participants collected data that could be analyzed to obtain kinetic parameters for the interaction. The association and the extended-dissociation data derived from the three antibody surfaces were globally fit using a simple 1:1 interaction model. The average k(a) and k(d) for the PSA/mAb interaction as calculated from the 22 analyses were (4.1+/-0.6) x 10(4) M(-1) s(-1) and (4.5+/-0.6) x 10(-5) s(-1), respectively. Overall, the experimental standard errors in the rate constants were only approximately 14%. Based on the kinetic rate constants, the affinity (K(D)) of the PSA/mAb interaction was 1.1+/-0.2 nM.

Experimental and data analysis protocols were developed to screen antibodies from hybridoma culture supernatants using Biacore surface plasmon resonance biosensor platforms. The screening methods involved capturing antibodies from crude supernatants using Fc-specific antibody surfaces and monitoring antigen binding at a single concentration. After normalizing the antigen responses for the amount of antibody present, a simple interaction model was fit to all of the binding responses simultaneously. As a result, the kinetic rate constants (k(a) and k(d)) and affinity (K(D)) could be determined for each antibody interaction under identical conditions. Higher-resolution studies involving multiple concentrations of antigen were performed to validate the reliability of single-concentration measurements. The screening protocols can be used to characterize antigen binding kinetics to approximately 200 antibody supernatants per day using automated Biacore 2000 and 3000 instruments.