Module 9 2024

03/09/2024

Testing for Immunogenicity - Timing

pre-clinical

clinical

post-licensure

Phase III Safety Efficacy

Discovery - Candidate selection

Phase I PK, PD Safety

Phase II Safety, Dose

Phase IV Post marketing

Toxicology

• The optimal time to design, develop, and validate ADA assays during therapeutic product development depends on the risk assessment of the product.

• Fit-for-purpose assays to test phase I and phase II studies samples - screening, confirmatory, and in some instances neutralisation assays. Immunogenicity assays often used to explain PK/PD/tox results.

• Samples derived from pivotal clinical studies (phase III) must be tested with fully validated assays.

• When immunogenicity poses a high clinical risk and real-time data are required, assays suitable for their intended purpose might need to be developed & validated before initiating clinical studies and testing performed in real time.

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Immunogenicity Testing – Assay Strategy

Multi-tiered approach:

test samples

• Screening assay: identification of samples / patients potentially positive for ADA. Detection of anti-drug antibodies (ADA): binding assays

ELISA (colorimetric detection method) ECL assays (electrochemiluminescence)

Screening Assay

• Confirmatory assays: elimination of false positives. Preferred approach: same assay format as screening assay but with therapeutic inhibition (competition using excess soluble drug).

negative samples

positive samples

Confirmatory Assay

• Titration assays – magnitude of immune response

• Neutralisation assays: assessment of the neutralising capacity of the detected antibodies. Bioassays Competitive ligand binding assays (non-cell based assays)

Confirmed positive samples

Titer Assay

NeutralisationAssay - bioassay or CLBA

• Further characterisation of induced antibodies (e.g., domain specificity, isotyping)

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