Selective Human FVIII Measurement via Capture Agent

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Solution Overview

Problem

Current assays face challenges in selectively measuring human factor VIII (FVIII) procoagulant activity in plasma, particularly in the presence of endogenous non-human FVIII or manufacturing-related additives, which can interfere with pharmacokinetic studies and FVIII measurement accuracy.

Innovation Solution

A method and kit utilizing a capture agent that selectively binds to human FVIII, allowing for its measurement in the presence of endogenous FVIII from other animals or manufacturing additives, using a chromogenic assay with specific reagents and conditions to isolate and quantify human FVIII activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional chromogenic assay is used to measure FVIII activity, then the assay can detect FVIII procoagulant activity, but it cannot selectively differentiate human FVIII from endogenous non-human FVIII in animal models

Engineering Contradiction:

Improveselectivity of human FVIII measurementVSAvoidapplicability in animal models with endogenous FVIII

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces a capture agent (antibody) as an intermediary that specifically binds to human FVIII before the chromogenic assay. This capture agent acts as a mediator that selectively captures human FVIII from the sample, allowing the subsequent chromogenic reagents to only detect the captured human FVIII and not the endogenous non-human FVIII present in animal models.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The assay is segmented into distinct steps: first, selective capture of human FVIII using a species-specific capture agent; second, washing to remove unbound components including endogenous non-human FVIII; third, addition of chromogenic reagents to measure only the captured human FVIII activity. This segmentation allows selective measurement despite the presence of interfering substances.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If conventional chromogenic reagents are used, then FVIII activity can be measured, but manufacturing process additives such as solvent/detergent mixtures interfere with assay performance

Engineering Contradiction:

Improveaccuracy of FVIII activity measurementVSAvoidinterference from manufacturing additives

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The capture agent serves as a protective intermediary that isolates the chromogenic reagents from interfering manufacturing additives. By capturing human FVIII specifically and removing unbound components through washing, the capture agent shields the subsequent chromogenic reaction from the harmful effects of solvent/detergent mixtures and other manufacturing additives.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The washing step extracts and removes interfering substances including solvent/detergent mixtures and unbound components from the sample before the chromogenic assay proceeds. This extraction eliminates the harmful factors that would otherwise interfere with assay performance.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If endogenous non-human FVIII is present in the sample, then the sample represents a realistic animal model condition, but the measurement of human FVIII becomes biased and inaccurate

Engineering Contradiction:

Improvevalidity of animal model studyVSAvoidaccuracy of human FVIII quantification

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The capture agent introduces local quality (species-specific binding capability) to the assay system. The capture agent is designed with specific affinity for human FVIII epitopes that are distinct from non-human FVIII, creating a localized selective recognition zone that discriminates between human and non-human FVIII molecules in the sample.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The capture agent mediates between the mixed FVIII population in the sample and the chromogenic detection system. It selectively binds human FVIII while leaving non-human FVIII unbound, thereby enabling accurate human FVIII quantification even in the presence of endogenous non-human FVIII that maintains realistic animal model conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 method enables precise and selective measurement of human FVIII activity, reducing interference from endogenous or manufacturing-related substances, thereby improving the accuracy of FVIII measurement in both animal models and manufacturing matrices.

Implementation Method 1

incubating the sample with a capture agent that selectively binds the human FVIII under conditions and for a time sufficient to allow the capture agent to selectively bind to the human FVIII

Methodology Applied

Scientific EffectSelective binding: Absorption (physical)

Implementation Method 2

adding to the reaction mixture an FXa specific chromogenic substrate and incubating the reaction mixture under conditions and for a time sufficient to generate a measurable signal

Methodology Applied

Scientific EffectEnzymatic reaction: Enzyme

Data Source

PatentUS20240353431A1Selective measurement of human factor viii

Publication Date: 2024.10.24 TAKEDA PHARMA CO LTD

AI summary

Described herein are methods and kits for selective and sensitive activity measurement of human coagulation factor VIII (FVIII).