Development of an automated, interference-free, 2D-LC-MS/MS assay for quantification of a therapeutic mAb in human sera.

AIM: Hybrid LC-MS/MS assays are increasingly used to quantitate proteins in biological matrices. These assays involve analyte enrichment at the protein level. Although suitability has been demonstrated, they are limited by the lack of appropriate affinity reagents and may suffer from interferences caused by binding proteins or antibodies. RESULTS: An online stable isotope standards and capture by anti-peptide antibodies assay was developed, which involves tryptic digestion of a therapeutic monoclonal antibody in human serum to destroy interfering proteins followed by enrichment using high affinity peptide antibodies. The assay was validated and compared with a standard ligand-binding assay currently used for quantification. CONCLUSION: The data show that the stable isotope standards and capture by anti-peptide antibodies-2D-LC-MS/MS assay can be used as an alternative method for measurement of monoclonal antibodies in clinical samples.

Use of generic LC-MS/MS assays to characterize atypical PK profile of a biotherapeutic monoclonal antibody.

BACKGROUND: The fully human monoclonal antibody mAb123, which binds to and neutralizes chemokine motif ligand-21 (CCL21) displays a faster clearance in cynomolgus monkey compared with typical IgG kinetics. A direct and an immunoaffinity LC-MS/MS assays were developed to compare with the previously established ligand-binding assays (LBAs). RESULTS: A strong correlation of LC-MS/MS pharmacokinetic data with LBA data confirmed the rapid drug disposition of mAb123 is an intrinsic property of the molecule, rather than interference of anti-mAb123 antibodies in the LBA. CONCLUSION: The data illustrate that in cases of unexpected results from LBA, application of orthogonal bioanalytical techniques such as LC-MS/MS can help in in interpretation of pharmacokinetic as determined by LBAs.