Immunogenicity refers to the ability of a substance to provoke an immune response. In biopharmaceuticals, the evaluation of immunogenicity is of great importance as it can impact drug efficacy, safety, and patient treatment outcomes. Unwanted immune responses against therapeutic proteins (such as monoclonal antibodies and recombinant proteins) can lead to the production of neutralizing antibodies (NAbs), altered pharmacokinetics, or severe adverse effects. This article examines the principles, methodologies, and regulatory considerations in evaluating immunogenicity.
Importance of Immunogenicity Evaluation
Clinical Safety – Immune responses can cause allergic reactions, anaphylaxis, or autoimmunity.
Drug Efficacy – Anti-drug antibodies (ADAs) may neutralize therapeutic effects.
Regulatory Requirements – Organizations such as the FDA, EMA, and ICH mandate immunogenicity testing for biopharmaceuticals.
Key Stages in Immunogenicity Evaluation
Risk Assessment
Factors influencing immunogenicity must be considered, which can relate to various aspects:
Product-related: Protein structure, aggregation, impurities.
Patient-related: Genetic background (such as HLA haplotypes), immune status.
Treatment-related: Dose, administration route, concomitant medications.
Screening for Anti-Drug Antibodies (ADAs)
Should be performed using the following methods:
ELISA – Identifies bound antibodies.
Electrochemiluminescence (ECL, e.g., Meso Scale Discovery system) – Higher sensitivity.
Surface Plasmon Resonance (SPR) – Label-free and real-time detection.
Confirmation and Characterization of Induced Responses
Confirmatory assays using competitive inhibition should be conducted to verify specificity.
Neutralizing antibody (NAb) assays can be performed in two forms:
Cell-based assays – Measure functional impact (e.g., inhibition of drug binding to receptor).
Non-cellular assays – Competitive ligand binding (e.g., ELISA-based methods).
Assessment of Clinical Impact
Pharmacokinetic (PK) Analysis – Reduction in drug levels due to clearance by ADAs.
Pharmacodynamic (PD) Markers – Changes in biomarker levels.
Clinical Outcomes – Loss of efficacy or adverse effects.
Conclusion
Evaluating immunogenicity is essential for the development of safe and effective biopharmaceuticals. A stepwise approach (screening → confirmation → characterization) ensures a comprehensive assessment. Emerging technologies such as multiparameter flow cytometry and next-generation sequencing (NGS) enhance the analysis of B cell receptor responses, improving the prediction and monitoring of immunogenicity.