Therapeutic Antibody Quantification via Mass Spectrometry
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Solution Overview
Problem
Current methods for quantifying therapeutic antibodies in human plasma and serum samples are challenging due to their low concentrations and high homology with endogenous human IgGs, leading to difficulties in accurately determining pharmacokinetic properties, especially with existing ELISA methods which are time-consuming and prone to matrix interference.
Innovation Solution
A method involving the addition of labeled therapeutic antibodies to a sample, followed by enzyme proteolysis and mass spectrometric analysis to determine the ratio of labeled to native peptides, allowing for precise quantification of therapeutic antibodies regardless of their type, using specific peptides unique to each antibody.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ELISA methods are used for quantifying therapeutic antibodies, then sensitivity is improved, but matrix interference increases and assay development time increases
Solution Approach 1:
The patent replaces the immunoassay-based ELISA mechanical system with a mass spectrometry-based detection system. Mass spectrometry measures the mass-to-charge ratio of ions, providing inherent specificity that eliminates matrix interference issues affecting ELISA. The method uses stable isotope-labeled internal standards and selected reaction monitoring to achieve accurate quantification without the cross-reactivity and interference problems of antibody-based assays.
Solution Approach 2:
The patent changes the detection parameter from optical signal measurement in ELISA to mass-to-charge ratio measurement in mass spectrometry. By monitoring specific peptide masses and fragmentation patterns, the method achieves high sensitivity while avoiding matrix interference, as mass spectrometry can distinguish target peptides from background proteins based on their unique mass signatures.
2Measurement precision
If ELISA methods are used for quantifying therapeutic antibodies, then sensitivity is improved, but assay development time increases
Solution Approach 1:
The patent establishes a universal mass spectrometry-based quantification method that can be applied to multiple therapeutic antibodies using the same general protocol. Unlike ELISA which requires custom antibody reagents and optimization for each target, the mass spectrometry method uses stable isotope-labeled internal standards and selected reaction monitoring parameters that can be adapted across different antibody targets, significantly reducing assay development time while maintaining sensitivity.
Solution Approach 2:
The patent performs preliminary proteolytic digestion of therapeutic antibodies into characteristic peptides before analysis. This pre-processing step creates consistent, identifiable peptide markers that can be monitored by mass spectrometry, eliminating the need for time-consuming ELISA reagent development and optimization while preserving the sensitivity required for low-concentration detection.
3Measurement precision
If mass spectrometry is used for protein quantification, then specificity is improved and matrix interference is reduced, but custom reagents are still required
Solution Approach 1:
The patent uses stable isotope-labeled versions of the therapeutic antibody itself as the internal standard, eliminating the need for separate custom reagents. The labeled antibody is digested with the same proteases to generate corresponding labeled peptides that serve as internal standards for quantification. This self-referential approach simplifies reagent preparation while maintaining the high specificity of mass spectrometry detection.
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
This method enables accurate, sensitive, and reproducible quantification of therapeutic antibodies, overcoming the limitations of existing techniques by providing a universal approach for various therapeutic antibodies, including anti-TNF and anti-cancer antibodies, without requiring specific kits or protocols.
Implementation Method 1
subjecting the pre-proteolysis sample to an enzyme proteolysis, so as to provide a proteolysis sample comprising (i) proteolysis labeled peptides derived from the labeled therapeutic antibodies and (ii) proteolysis peptides derived from the therapeutic antibody contained in the test sample
Implementation Method 2
determining by mass spectrometric analysis the ratio between (i) one or more selected proteolysis labeled peptides and (ii) one or more corresponding proteolysis peptides derived from the said therapeutic antibody
Data Source
AI summary
The present invention relates to a method for quantifying a therapeutic antibody in a sample of a human individual comprising a step of adding to a test sample which may contain therapeutic antibodies to be quantified a known amount of two or more labeled forms of said therapeutic antibodies.