ISV C-Terminal Modification for ADA Assay Accuracy

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Solution Overview

Problem

Existing methods for detecting anti-drug antibodies (ADA) in assays involving immunoglobulin single variable domains (ISVs) fail to account for aspecific protein interference, leading to inaccurate results due to interactions with pre-existing proteins in biological samples.

Innovation Solution

Modifying the C-terminal end of ISVs with a limited number of amino acid residues, such as adding a single alanine, to reduce or eliminate solvent-exposed hydrophobic patches, thereby minimizing protein interference in ADA assays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ISVs are used in ADA assays, then the assays can detect anti-drug antibodies, but aspecific protein interference occurs leading to inaccurate results

Engineering Contradiction:
Improveaccuracy of ADA detectionVSAvoidaspecific protein interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by making a specific modification at the C-terminal end of the ISV (adding limited amino acid residues) to alter the local properties of the hydrophobic patch. This localized modification reduces asspecific protein interference while preserving the overall antigen-binding function of the ISV, thereby improving measurement precision without sacrificing the detection capability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the chemical parameter of the ISV by adding limited amino acid residues (such as alanine) at the C-terminal end. This parameter change modifies the hydrophobicity and solvent exposure of the C-terminal region, reducing asspecific protein interactions and improving the accuracy of ADA assays while maintaining the ISV's functional properties.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the C-terminal end of ISVs is modified with amino acid residues, then protein interference is reduced, but the structural complexity of the ISV increases

Engineering Contradiction:
Improveprotein interferenceVSAvoidstructural complexity of ISV
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies partial action by adding only a limited number of amino acid residues (such as a single alanine or a small sequence) at the C-terminal end of the ISV. This minimal modification is sufficient to reduce asspecific protein interference and improve assay accuracy while avoiding excessive structural complexity. The modification is deliberately kept small to balance the reduction of harmful effects with minimal increase in structural complexity.

Inventive Principle:
Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The modification effectively predicts and reduces aspecific protein interference, ensuring accurate detection of ADA in biological samples by minimizing false signals, thus improving the reliability of ADA assays.

Implementation Method 1

modifying the C-terminal end of said ISV with a limited number of amino acid residues... to reduce or eliminate solvent-exposed hydrophobic patches, thereby minimizing protein interference

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Data Source

PatentEP2974737B1Techniques for predicting, detecting and reducing a specific protein interference in assays involving immunoglobulin single variable domains
Publication Date: 2025.10.22 ABLYNX NV
  • EP2974737B1 patent drawingFigure 1A
  • EP2974737B1 patent drawingFigure 1B
  • EP2974737B1 patent drawingFigure 1C

AI summary

This invention provides, and in certain specific but non-limiting aspects relates to: assays that can be used to predict whether a given ISV will be subject to protein interference as described herein and/or give rise to an (aspecific) signal in such an assay (such as for example in an ADA immunoassay). Such predictive assays could for example be used to test whether a given ISV could have a tendency to give rise to such protein interference and/or such a signal; to select ISV's that are not or less prone to such protein interference or giving such a signal; as an assay or test that can be used to test whether certain modification(s) to an ISV will (fully or partially) reduce its tendency to give rise to such interference or such a signal; and/or as an assay or test that can be used to guide modification or improvement of an ISV so as to reduce its tendency to give rise to such protein interference or signal; - methods for modifying and/or improving ISV's to as to remove or reduce their tendency to give rise to such protein interference or such a signal; - modifications that can be introduced into an ISV that remove or reduce its tendency to give rise to such protein interference or such a signal; ISV's that have been specifically selected (for example, using the assay(s) described herein) to have no or low(er)/reduced tendency to give rise to such protein interference or such a signal; modified and/or improved ISV's that have nor or a low(er)/reduced tendency to give rise to such protein interference or such a signal.