FcRn Antagonist Fc Variants for Rapid Serum IgG Reduction

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Solution Overview

Problem

There is a need for agents that can antagonize the binding of IgG to FcRn to reduce the serum half-life of IgG and treat autoimmune diseases and other antibody-mediated disorders.

Innovation Solution

Development of FcRn antagonist molecules, comprising variant Fc regions with specific amino acid sequences and glycan modifications, which inhibit the binding of IgG to FcRn, thereby reducing serum IgG levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If FcRn binding to IgG is inhibited, then serum IgG levels are reduced, but the mechanism complexity increases

Engineering Contradiction:

Improveserum IgG levelsVSAvoidmechanism complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent uses FcRn antagonist molecules as intermediary substances that bind to FcRn and prevent IgG from binding to FcRn. These antagonists act as mediators that block the recycling pathway, causing IgG to be degraded instead of being recycled back to the extracellular compartment, thereby reducing serum IgG levels without directly destroying IgG molecules.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the binding parameters of the FcRn-IgG interaction by introducing antagonist molecules that change the affinity and kinetics of the interaction. The antagonists alter the pH-dependent binding characteristics and prevent the high-affinity binding that occurs at acidic endosomal pH, thereby disrupting the recycling mechanism and reducing serum IgG half-life.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If FcRn recycling function is blocked, then IgG degradation is prevented, but therapeutic specificity may be reduced

Engineering Contradiction:

ImproveIgG degradation preventionVSAvoidtherapeutic specificity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The FcRn antagonist molecules are designed with specific structural features that allow them to bind selectively to FcRn under certain conditions. The antagonists exhibit pH-dependent binding characteristics, allowing them to preferentially bind to FcRn at acidic pH levels (such as in endosomes) while having reduced binding at physiological pH, thereby providing condition-specific therapeutic activity with reduced off-target effects.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs multiple FcRn antagonist molecules with different structural and functional characteristics in a combination therapy approach. This segmentation of the therapeutic strategy allows for targeted disruption of FcRn-IgG binding under different physiological conditions, enhancing therapeutic specificity while maintaining effective IgG degradation prevention.

Inventive Principle:

Principle #1Segmentation

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 FcRn antagonist molecules effectively and rapidly decrease serum IgG levels, providing a therapeutic approach for autoimmune diseases and other disorders by preventing IgG recycling and degradation.

Implementation Method 1

The IgG/FcRn interaction is stronger at acidic endosomal pH than at extracellular physiological pH

Methodology Applied

Scientific EffectpH dependent binding:

Data Source

PatentUS20250368741A1Fcrn antagonist molecules and methods of use thereof

Publication Date: 2025.12.04 ARGENX BVBA(BE)

AI summary

The disclosure provides populations of FcRn antagonist molecules, mixtures of these populations and methods of using these populations to reduce the level of serum IgG autoantibodies in a subject.