A Phase I Clinical Trial to Evaluate the Bioequivalence of an Adalimumab Biosimilar Adalimumab-WIBP and Humira®.

Background and objectives: The high costs associated with biological agents often limit accessibility for many patients, whereas biosimilars allow the wider application of biological treatment. The objectives of this phase I clinical trial were to compare the pharmacokinetics, immunogenicity, and safety profiles of the biosimilar adalimumab-WIBP and the reference product Humira^® and to assess the precision of the bioequivalence evaluation.

Methods: In this randomized, double-blind, parallel-group bioequivalence study, 164 healthy male Chinese participants were selected and randomly divided into two groups on a 1:1 ratio. The subjects were administered a single 40 mg subcutaneous dose of either adalimumab-WIBP or Humira^®. Blood samples extracted at multiple intervals after administration were analyzed to interpret pharmacokinetic parameters, and any adverse events were documented. Alongside ensuring safety measures, the subjects were monitored for immunogenicity.

Results: The pharmacokinetic results demonstrated similar serum concentration-time curves in both groups. There were no significant differences in safety and no differences in immunogenicity profiles between the two groups. The bioequivalence was confirmed: the 90% confidence interval for the geometric mean ratio of the main pharmacokinetic parameters was within the range of 80-125%.

Conclusion: The trial indicated the bioequivalence between adalimumab-WIBP and the reference product Humira^® based on pharmacokinetics, immunogenicity, and safety profile. These findings reinforce the use of the adalimumab-WIBP biosimilar as a possible therapeutic alternative to Humira^®.