2020 Volume 51 Issue 3 Pages 161-166
Although ligand binding assays are commonly used for the determination of serum concentrations of monoclonal antibody drugs in humans, the serum concentrations measured by these assays are potentially increased by cross-reaction with endogenous proteins and decreased by the presence of neutralizing antibodies. Recently, proteomic approaches using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) have been employed for the measurement of monoclonal antibody drugs in human specimens. For serum concentrations of monoclonal antibody drugs, the proteomic approaches require complicated pretreatment processes including immunopurification, denaturation, reduction, alkylation, tryptic digestion, desalination, clean-up, and reconstitution. These pretreatment processes are time-consuming and potentially cause analytical variations. To date, the proteomic approaches using LC-MS/MS methods have not been fully applied to clinical practice. We have constructed quantitative analysis workflow that uses a signature peptide selected by Fourier transform mass spectrometer to ensure its uniqueness in human serum, extracts serum immunoglobulins with immobilized Protein G to reduce the matrix effect if needed, and employs immobilized trypsin for rapid protein digestion. The entire pretreatment and quantitation using the present LC-MS/MS method can be completed within one day. Additionally, the analytical performance data obtained from these methods meet the standards of international guidance. The present report describes the construction of quantitative analysis workflow for measurement of monoclonal antibody drugs in human serum. Our approaches would contribute to promote therapeutic drug monitoring of monoclonal antibody drugs in clinical practice.
