The Biotherapeutics industry is rapidly modifying and developing new Biotherapeutics into complex molecules with multi-functional domains for specific biological functions. Immunogenicity testing is now mandatory part of any Biotherapeutic development.


Immunogenicity is the ability of an antigen or epitope to elicit an immune response in the body of an animal or Human. In short, it is the ability to induce humoral and/or cell-mediated immune responses. While stating it this way understates the complexity of the human immune response, the ability to detect and measure the resulting Anti-Drug Antibodies (ADAs) or Neutralizing Anti-Drug Antibodies (Nabs) in humans is not an easy process.


ADA assays can no longer be an afterthought. Mandated by the agencies, it is now part of the pre-clinical process and validated assays are required prior to Phase I testing. Immunogenicity testing is a complex population based statistical analysis and semi-quantitative complex set of assays that have multiple steps and components to it:


  • Screening assays, also known as binding antibody assays, are used to detect antibodies that bind to the therapeutic protein product.
  • Confirmatory assays determine specificity of ADA/Nab for the therapeutic protein product by competition with the therapeutic protein drug.
  • Titration assays characterize the assays magnitude of the ADA/Nab responses. This is important to characterize the magnitude with titration assays because of the impact of ADAs/Nabs on Pharmacokinetics, Safety, etc.


Depending on the complexity of your Biotherapeutic, you may have to develop multiple ADA assays for one therapeutic product. Therapeutic Domains, multiple binding sites, recombinant proteins coupled to Peg-linkers, ADC’s, Bi-specific antibodies, Fusion proteins, etc. all contribute to the complexity of the ADA assay. One Biotherapeutic can have up to 4 separate ADA assays. If it is confirmed that you do have ADAs with your Biotherapeutic, you will be asked for a Nab assay before you can progress in your clinical studies.


KCAS is a CRO that not only understands how to develop an ADA/Nab assay for your unique biotherapeutics, but can assist you in the development of an immunogenicity testing strategy. Some of the services we offer regarding immunogenicity are method development and validation including a statistically robust method for determining a cut point for your assay that exceeds FDA expectations, resolving endogenous interferences, improving drug tolerance challenges, etc.  When your program is approaching the critical phase of development, call KCAS, we will ensure you have the best assays to enable the success of your therapeutic protein program.


If you have any thoughts or questions, please use the form below. Additionally, you can reach out to John Pirro directly, or any other member of KCAS’ leadership team. Thank you.


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