Basic StudiesT-cell Activating Tribodies as a Novel Approach for Efficient Killing of ErbB2-positive Cancer CellsRiccio, Gennaro*; Ricardo, Ana Rita†; Passariello, Margherita‡,§; Saraiva, Kathy†; Rubino, Valentina∥; Cunnah, Philip†; Mertens, Nico¶; De Lorenzo, Claudia‡,§Author Information *Department of Pharmacy ‡Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II §CEINGE Biotecnologie Avanzate s.c.a.r.l., Naples ∥Department of Science, University of Basilicata, Viale dell’Ateneo Lucano, Potenza, Italy †Rodon Biologics, Oeiras, Portugal ¶Biotecnol Limited, LBIC, London, UK Reprints: Claudia De Lorenzo, Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via S. Pansini 5, Naples, Italy, CEINGE Biotecnologie Avanzate s.c.a.r.l., Via G. Salvatore 486, 80145 Naples, Italy (e-mail: email@example.com). Journal of Immunotherapy: January 2019 - Volume 42 - Issue 1 - p 1-10 doi: 10.1097/CJI.0000000000000248 Buy SDC Metrics Abstract The Tyrosine Kinase Receptor ErbB2 (HER2) when overexpressed in breast cancer (BC) is associated with poor prognosis. The monoclonal antibody Trastuzumab has become a standard treatment of ErbB2+BC. The antibody treatment has limited efficacy, often meets resistance and induces cardiotoxicity. T-cell recruiting bispecific antibody derivatives (TRBA) offer a more effective alternative to standard antibody therapy. We evaluated a panel of TRBAs targeting 3 different epitopes on the ErbB2 receptor either in a bivalent targeting tribody structure or as a monovalent scFv-fusion (BiTE format) for binding, cytotoxicity on Trastuzumab-resistant cell lines, and induction of cardiotoxicity. All three TRBAs bind with high affinity to the ErbB2 extracellular domain and a large panel of ErbB2-positive tumor cells. Tribodies had an increased in vitro cytotoxic potency as compared to BiTEs. It is interesting to note that, Tribodies targeting the epitopes on ErbB2 receptor domains I and II bind and activate lysis of mammary and gastric tumor cells more efficiently than a Tribody targeting the Trastuzumab epitope on domain IV. The first 2 are also active on Trastuzumab-resistant cancer cells lacking or masking the epitope recognized by Trastuzumab. None of the Tribodies studied showed significant toxicity on human cardiomyocytes. Altogether these results make these novel anti-ErbB2 bispecific Tribodies candidates for therapeutic development for treating ErbB2-positive Trastuzumab-resistant cancer patients. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.