title: Molecular characterization of novel trispecific ErbB-cMet-IGF1R antibodies and their antigen-binding properties.
abstract: Therapeutic antibodies are well established drugs in diverse medical indications. Their success invigorates research on multi-specific antibodies in order to enhance drug efficacy by co-targeting of receptors and addressing key questions of emerging resistance mechanisms. Despite challenges in production, multi-specific antibodies are potentially more potent biologics for cancer therapy. However, so far only bispecific antibody formats have entered clinical phase testing. For future design of antibodies allowing even more targeting specificities, an understanding of the antigen-binding properties of such molecules is crucial. To this end, we have generated different IgG-like TriMAbs (trispecific, trivalent and tetravalent antibodies) directed against prominent cell surface antigens often deregulated in tumor biology. A combination of surface plasmon resonance and isothermal titration calorimetry techniques enables quantitative assessment of the antigen-binding properties of TriMAbs. We demonstrate that the kinetic profiles for the individual antigens are similar to the parental antibodies and all antigens can be bound simultaneously even in the presence of FcγRIIIa. Furthermore, cooperative binding of TriMAbs to their antigens was demonstrated. All antibodies are fully functional and inhibit receptor phosphorylation and cellular growth. TriMAbs are therefore ideal candidates for future applications in various therapeutic areas.
authors.affiliation: Discovery Oncology Department, Roche Diagnostics GmbH, 81377 Penzberg,  Germany.
authors.forename: R
authors.initials: R
authors.lastname: Castoldi
authors.forename: U
authors.initials: U
authors.lastname: Jucknischke
authors.forename: L P
authors.initials: LP
authors.lastname: Pradel
authors.forename: E
authors.initials: E
authors.lastname: Arnold
authors.forename: C
authors.initials: C
authors.lastname: Klein
authors.forename: S
authors.initials: S
authors.lastname: Scheiblich
authors.forename: G
authors.initials: G
authors.lastname: Niederfellner
authors.forename: C
authors.initials: C
authors.lastname: Sustmann
mesh_terms: D018033:Antibodies, Bispecific / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology; D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D003001:Cloning, Molecular; D066246:ErbB Receptors / Q000276:immunology*; D006801:Humans; D008958:Models, Molecular; D019859:Proto-Oncogene Proteins c-met / Q000276:immunology*; D020893:Receptor, ErbB-3 / Q000276:immunology*; D017526:Receptor, IGF Type 1 / Q000276:immunology*
chemical_list: D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; D066246:ErbB Receptors; D019859:Proto-Oncogene Proteins c-met; D020893:Receptor, ErbB-3; D017526:Receptor, IGF Type 1