Validation of A Biotherapeutic Immunoaffinity-LC–MS/MS Assay in Monkey Serum: ‘Plug-And-Play’ Across Seven Molecules

BACKGROUND: Biotherapeutics development requires validated assays in biological matrices for pharmacokinetic assessment. Historically, ligand-binding assays have been the predominant platform available. Recently, alternative hybrid methods, combining ligand-binding analyte enrichment with LC-MS detection have emerged. Methodology & results: The validation of an immunoaffinity (IA)-LC-MS/MS method to quantify a monoclonal antibody biotherapeutic in cynomolgus monkey serum is described. This method includes immunoaffinity capture of the antibody in serum, followed by enzymatic digestion and detection of a framework peptide. Using similar method conditions, six additional biotherapeutic assays were readily validated in different nonhuman mammalian species, including mouse, rat and monkey. CONCLUSION: The immunoaffinity-LC-MS/MS assay validation results across seven antibody therapeutics, using comparable conditions, illustrate the 'plug-and-play' nature of the IA-LC-MS/MS mAb framework peptide assay format.