Population Pharmacokinetic Modeling of Adalimumab Biosimilar SCT630 and Humira® in Healthy Participants and Patients with Moderate to Severe Plaque Psoriasis to Establish PK Similarity

Objective SCT630 is a recombinant fully human anti-TNF-α IgG1 monoclonal antibody developed as a biosimilar to adalimumab reference product Humira® (AbbVie). This study aims to evaluate the pharmacokinetic (PK) similarity, characterize pharmacokinetics between healthy participants and patients, and identify potential sources of PK variability of SCT630 and Humira® using population pharmacokinetic modeling approach. Methods A population pharmacokinetic model was developed using PK data from a phase I study in healthy participants and a phase III study in patients with moderate to severe plaque psoriasis (PsO). Results A one-compartment PopPK model with first-order linear elimination adequately described SCT630 and Humira® concentration data. The covariates analysis identified anti-drug antibody, body weight, total bilirubin, alanine aminotransferase, participant type and study drug as significant covariates affecting clearance and volume of distribution. Model-predicted exposures, including C max and AUC were obtained, and their geometric mean ratios (test versus the reference group) were calculated. The 90% confidence intervals (CI) for all these ratios fell entirely within the range of 80.00% to 125.00%. Conclusion This analysis integrated data from both healthy participants and patients with PsO, and provided a valuable assessment of adalimumab PK characteristics and significant covariates. This model-based approach further elucidates how the SCT630 PK profile compares to that of Humira® in healthy participants and patients with PsO, supporting the totality-of-evidence for the biosimilarity of SCT630.