MSACL 2022 Abstract

Background:
Surface Plasmon Resonance is a powerful technology for characterization of ligand binding interactions between biological molecules. The biosensor detects changes in optical resonance when an analyte binds to a molecule that has been immobilized to a gold surface. Few descriptions of the use of SPR in the clinical laboratory for quantitative analysis have been reported.

Objective:
Certolizumab Pegol (Cimzia®) is a biologic drug that is a PEGylated Fab’ fragment of a monoclonal antibody specific to tumor necrosis factor alpha (TNF-α). Certolizumab Pegol and other biologics are monoclonal antibody therapeutic proteins (MATs) used to treat a variety of diseases. Therapeutic drug monitoring (TDM) of drug and anti-drug antibodies (ADA) is often used to evaluate individual responses to MATs and guide personalized treatment regimens. In this study a ligand binding assay for the biologic drug Certolizumab Pegol using Surface Plasmon Resonance (SPR) technology was developed.

Methods:
Anti TNF-α Antibody is covalently immobilized onto a SPR biosensor by amine coupling. TNF-α is then flowed over the biosensor and acts as a capture molecule for the Certolizumab Pegol in standards, controls, and patient samples. Next, standards, controls, and unknowns are diluted in phosphate buffer before being flowed over the biosensor. Finally, an antibody specific to Certolizumab Pegol is flowed over the biosensor to add specificity and enhance the final signal obtained in each sensorgram. The final enhanced signal is measured, and the Certolizumab Pegol concentration in each unknown sample and control is interpolated from a standard curve generated with each assay.

Results:
The analytical sensitivity was 1 ug/mL with an analytical measurement range up to 90 ug/mL (up to 900 ug/mL on dilution). Inter-assay precision ranged from 4.0% to 8.0%. Inter-assay accuracy, as measured by spike recovery, ranged from 96.5% to 113.9%. The method was verified to be specific for Certolizumab Pegol by testing alternative biologics that are targeted to TNF-α including Adalimumab, Golimumab, Infliximab and Enbrel. No interference was observed in the presence of hemolysis, icteric or lipemia. No difference in result was observed when using collection tubes containing EDTA, Heparin or gel barriers. Specimen stability was interrogated at ambient, refrigerated and frozen conditions. Samples from patients prescribed Certolizumab Pegol were tested as part of the validation.

Conclusion:
A method for quantitation of Certolizumab Pegol has been validated for clinical use using Surface Plasmon Resonance detection.