The FDA recently released final guidance on the use of therapeutic proteins in developing biologics and biosimilars. "Immunogenicity Testing of Therapeutic Protein Products—Developing and Validating Assays for Anti-Drug Antibody Detection" represents current FDA thinking about developing and validating assays for anti-drug antibody (ADA) detection.
The FDA recently released final guidance about the use of therapeutic proteins in developing biologics and biosimilars. "Immunogenicity Testing of Therapeutic Protein Products—Developing and Validating Assays for Anti-Drug Antibody Detection" represents current FDA thinking about developing and validating assays for anti-drug antibody (ADA) detection.
The FDA recommends a multi-tiered testing approach, and the document spells out the development and validation of screening assays, confirmatory assays, titration assays, and neutralization assays. Screening assays, also known as binding antibody assays, are used to detect antibodies that bind to the therapeutic protein product. Confirmatory assays establish the specificity of ADAs for the therapeutic protein. Titration assays characterize the magnitude of the ADA response. Neutralization assays assess ADA for neutralizing activity.
The agency notes that setting the appropriate cut-point in assays “is critical to minimizing the risk of false-negative results.”
The document also discusses considerations for assay:
There may be other considerations, such as the use of pre-existing antibodies, rheumatoid factor, monoclonal antibodies, and conjugated proteins, the document noted.
The FDA recommends that sponsors adopt a life-cycle management report, including these sections as the product moves through various stages:
On a case-by-case basis, the FDA said, the guidance may also apply to some peptides, oligonucleotides, and combination products.
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