GloBody Technology: Detecting Anti-Drug Antibody against VH/VL domains

Gauri K Saxena,Klaus Schmierer,Gavin Giovannoni,Sharmilee Gnanapavan,Meleri Jones,James A Garnett,David Baker,Angray S Kang,Nisha Thaslima Aziz,Ioannis Theocharopoulos

doi:10.1038/s41598-020-58041-3

Abstract

The occurrence of anti-drug antibodies following administration of therapeutic monoclonal antibody to patients is a growing problem that is attracting attention from frontline clinicians. Ideally, an initial indicative point of care test would provide guidance to seek testing approved by the regulatory authorities. Here we describe a platform for the detection of IgG anti-drug antibodies that may provide an initial screen for all therapeutic monoclonal antibodies. Synthetic genes encoding Nanoluciferase polypeptides were inserted between the variable heavy and light domain encoding region of known antibody drugs (alemtuzumab and adalimumab) to generate recombinant single chain GloBodies, which retain the drug antibody paratopes and Nanoluciferase activity. In the presence of anti-drug antibodies, the GloBody is bound by specific IgG in the sample. These complexes are captured on immobilised Protein G and the luciferase activity determined. The amount of light generated being indicative of the anti-drug IgG antibody levels in serum. It should be possible to assemble GloBody reagents for all therapeutic monoclonal antibodies and adapt the capture phase to include additional specific isotypes. The assay has the potential to be developed for use with a drop of blood allowing initial pre-screening in a point of care setting.

Highlights

The immunogenicity of therapeutic monoclonal antibodies is a major concern for patient safety and for biopharmaceutical companies developing products for unmet needs
We investigated Campath-1H, the first humanised monoclonal antibody[8] known as alemtuzumab (Lemtrada) that is used to treat relapsing multiple sclerosis (RMS)
Since the anti-drug antibody (ADA) with the potential to be inhibitory are directed against the variable regions of the antibody drug, a minimal structure for detecting ADA would require the VH and VL assembled to form a functional binding site mimicking the structure of the antibody drug

Summary

Introduction

The immunogenicity of therapeutic monoclonal antibodies (mAbs) is a major concern for patient safety and for biopharmaceutical companies developing products for unmet needs. In the bridging assays, the capture and detection reagents require optimisation on a case-by-case basis for capture and detection (i.e., for immobilisation, biotin/enzyme/fluorophore labelling) This has partially been resolved by fusing Nanoluciferase (Nluc) to the C-terminus of the heavy chains of the drug antibody to generate a uniform IgG based reporter[7]. A test for IgG ADA following the second treatment course prior to the third and subsequent rounds of treatment is needed as potentially neutralizing ADA may have developed[10]. In this communication, we describe a novel IgG ADA assay for the detection of IgG anti-alemtuzumab binding antibody in people with MS treated with this drug. The assay has the potential to be developed for use with a drop of blood allowing initial pre-screening in a point of care setting and identifying individuals for testing for neutralising ADA using a cell based assay

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