Journal Article

Trastuzumab does not bind rat or mouse ErbB2/neu: implications for selection of non-clinical safety models for trastuzumab-based therapeutics

Shen, Ben-Quan, Lewis Phillips, Gail, Kiefer, James R., Proctor, William, Guo, Jun, Bumbaca Yadav, Daniela, Dybdal, Noel

2022

Overview

Purpose Assessment of non-clinical safety signals relies on understanding species selectivity of antibodies. This is particularly important with antibody–drug conjugates, where it is key to determine target-dependent versus target-independent toxicity. Although it appears to be widely accepted that trastuzumab does not bind mouse or rat HER2/ErbB2/neu, numerous investigators continue to use mouse models to investigate safety signals of trastuzumab and trastuzumab emtansine (T-DM1). We, therefore, conducted a broad array of both binding and biologic studies to demonstrate selectivity of trastuzumab for human HER2 versus mouse/rat neu. Methods Binding of anti-neu and anti-HER2 antibodies was assessed by ELISA, FACS, IHC, Scatchard, and immunoblot methods in human, rat, and mouse cell lines. In human hepatocytes, T-DM1 uptake and catabolism were measured by LC-MS/MS; cell viability changes were determined using CellTiter-Glo. Results Our data demonstrate, using different binding methods, lack of trastuzumab binding to rat or mouse neu. Structural studies show important amino acid differences in the trastuzumab-HER2 binding interface between mouse/rat and human HER2 ECD. Substitution of these rodent amino acid residues into human HER2 abolish binding of trastuzumab. Cell viability changes, uptake, and catabolism of T-DM1 versus a DM1 non-targeted control ADC were comparable, indicating target-independent effects of the DM1-containing ADCs. Moreover, trastuzumab binding to human or mouse hepatocytes was not detected. Conclusions These data, in total, demonstrate that trastuzumab, and by extension T-DM1, do not bind rat or mouse neu, underscoring the importance of species selection for safety studies investigating trastuzumab or trastuzumab-based therapeutics.

• Publisher: Springer US,Springer,Springer Nature B.V
• Subject: Amino acid substitution / Amino acids / Animal models / Animals / Antibodies / Antibodies, Monoclonal, Humanized / Antigens / Biological products / Breast cancer / Breast Neoplasms / Cancer research / Cell lines / Cell viability / Chromatography, Liquid / Enzyme-linked immunosorbent assay / ErbB-2 protein / Ethylenediaminetetraacetic acid / Female / Flow cytometry / Hepatocytes / Homeopathy / Humans / Kinases / Materia medica and therapeutics / Maytansine - adverse effects / Medical research / Medicine / Medicine & Public Health / Mice / Monoclonal antibodies / Oncology / Pertuzumab / Pharmacokinetics / Preclinical Study / Rats / Reagents / Receptor, ErbB-2 - genetics / Safety / Safety and security measures / Tandem Mass Spectrometry / Targeted cancer therapy / Therapeutics / Toxicity / Trastuzumab / Trastuzumab - adverse effects