Label-free interaction analysis as a tool to demonstrate biosimilarity of therapeutic monoclonal antibodies

Abstract:

In the biosimilar eon, where various analytical platforms are needed to show biosimilarity, we demonstrate the use of surface plasmon resonance biosensor as a label-free interaction analysis tool to compare two therapeutic monoclonal antibodies (mAb1-i and mAb2-i) with their biosimilars (mAb1-B and mAb2-B1, B2, B3) based on kinetics, affinity, and thermal stability studies. We calculate active analyte concentration using Biacore systems’ calibration-free concentration analysis method and demonstrate its importance for kinetic evaluation. The kinetic constants (k_a and k_d) and affinity constant (K_D) of the mAbs for binding to specific antigens were evaluated. It was found that the biosimilars were very similar to their innovator with respect to binding to its antigen demonstrating functional similarity. To further confirm biosimilarity to the originator molecules, we conducted a thermal stability analysis of both mAbs using differential scanning calorimetry. This analysis showed good structural similarity in between innovator antibodies and biosimilars, with major T_m as 84.1°C (mAb1) and 72.8°C (mAb2), demonstrating structural similarity.

Keywords::

• surface plasmon resonance
• Biacore
• kinetics
• low level of ligand immobilization
• calibration-free concentration analysis
• bivalent analytes
• active concentration

Acknowledgments

We would like to thank Dr Ewa Pol, Scientist, GE Healthcare, Sweden, for reviewing the technical data. We thank Dr Marco Marenchino (Application Specialist, Malvern Instruments) for guiding us during the DSC experimental setup. We would also like to acknowledge Dr Rajesh Bhagwat (Business leader, Thermo Fisher Scientific) for initiating and supporting this project during his tenure in GE.

Disclosure

The authors report no conflicts of interest in this work.