Fabrizia Fusetti is the Scientific Director Bioanalysis at QPS Netherlands. Fabrizia obtained her PhD in Molecular Biology and Biotechnology at the University of Milan (Italy), after which she spent several years in academia and participated in numerous fundamental and applied research projects mainly focused on the study of proteins. Her work contributed to over 50 peered reviewed publications. Before joining QPS in 2014, she started and managed one of the proteomics platforms at the University of Groningen. She is particularly interested in the development of mass spectrometry methods for bioanalysis of recombinant proteins, antibodies, ADCs, peptides and oligonucleotides. The need for multiplex PK assay is growing together with the increasing use of multiple monoclonal antibodies (mAbs) in combination therapies. For the frequently co-administered anti-Human Epidermal growth factor Receptor 2 (HER2) mAbs trastuzumab and pertuzumab we developed a high-throughput and robust hybrid ligand-binding LC–MS/MS quantitative method. Nanomolar concentrations of trastuzumab and pertuzumab were determined after extraction by protein A affinity purification followed by trypsin digestion. The method, validated according to the current FDA/EMA guidelines for large molecule bioanalysis, was accurate and selective for the simultaneous determination of trastuzumab and pertuzumab in clinical samples, thereby overcoming the limitation of ligand binding assays that are challenged by mAbs targeting the same receptor. The assay was applied to support a late phase clinical study investigating the addition of co-administered trastuzumab and pertuzumab to standard curative treatments in esophageal cancer patients. The described generic bioanalytical strategy can easily be adapted to multiplex quantifications of other mAb combinations in non-clinical and clinical samples¹.

¹Schokker, S, Fusetti, F, Bonardi, F, Molenaar, RJ, Mathôt, RAA, van Laarhoven, HWM, (2020) Development and validation of an LC-MS/MS method for simultaneous quantification of co-ad- ministered trastuzumab and pertuzumab. mAbs 12 (1), 1795492