Prospective ICH Q2(R2)-Aligned Total-Error Validation of Label-Free Untargeted Proteomics for Host Cell Protein Quantification in Biotherapeutics

This 2026 study by Somar Khalil, Jean-François Dierick, Pascal Bourguignon and Michel Plisnier from GSK presents what the authors describe as the first prospective ICH Q2(R2)-aligned validation of untargeted proteomics for host cell protein (HCP) quantification.

The work establishes a regulatory-oriented framework that enables advanced LC-MS/MS proteomics workflows to move closer to routine biopharmaceutical quality control.

Why This Article Matters

Untargeted proteomics has long been recognised as a powerful alternative to traditional HCP assays because it provides protein-specific information rather than a single composite signal. However, regulatory validation of these complex workflows has remained a major challenge.

This study demonstrates how identification control, quantitative performance, robustness, and lifecycle management can be integrated into a single validation strategy aligned with modern ICH expectations.

Highlights

First ICH Q2(R2)-Aligned Validation of Untargeted Proteomics
The authors present what they describe as the first prospective validation of an untargeted proteomics workflow for HCP quantification under ICH Q2(R2), addressing a key gap in regulatory acceptance.

Novel Total Error Validation Strategy
The study uses a Total Error framework that combines trueness and precision into a single validation approach, providing a more comprehensive assessment of analytical performance.

Strong Identification Confidence
A dual-entrapment strategy was applied to experimentally verify peptide identification error rates below 1%, increasing confidence in the reliability of the generated data.

Extensive Validation Dataset
The validation included seven concentration levels, four independent assays, and 198 LC-MS/MS injections, creating a strong statistical foundation for method evaluation.

Abundance-Aware Quantification
The authors introduced abundance-stratified validation, resulting in an abundance-aware lower limit of quantification of 3.6 ppm.

Demonstrated Cross-Platform Robustness
Performance remained consistent across different software pipelines and mass spectrometry platforms, supporting future implementation in diverse laboratory environments.

Takeaway

This study represents an important milestone for biopharmaceutical analytics. By demonstrating that untargeted proteomics can be validated within an ICH Q2(R2)-aligned framework, the authors provide a practical pathway for bringing advanced LC-MS/MS workflows into regulated quality control laboratories.

Article Information

• Authors: Somar Khalil, Jean-François Dierick, Pascal Bourguignon, Michel Plisnier
• Organisation(s): GSK
• Journal: Proteomes
• Year: 2026

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