title: In vivo evaluation of a novel format of a bivalent HER3-targeting and albumin-binding therapeutic affibody construct.
abstract: Overexpression of human epidermal growth factor receptor 3 (HER3) is involved in resistance to several therapies for malignant tumours. Currently, several anti-HER3 monoclonal antibodies are under clinical development. We introduce an alternative approach to HER3-targeted therapy based on engineered scaffold proteins, i.e. affibody molecules. We designed a small construct (22.5 kDa, denoted 3A3), consisting of two high-affinity anti-HER3 affibody molecules flanking an albumin-binding domain ABD, which was introduced for prolonged residence in circulation. In vitro, 3A3 efficiently inhibited growth of HER3-expressing BxPC-3 cells. Biodistribution in mice was measured using 3A3 that was site-specifically labelled with111In via a DOTA chelator. The residence time of111In-DOTA-3A3 in blood was extended when compared with the monomeric affibody molecule.111In-DOTA-3A3 accumulated specifically in HER3-expressing BxPC-3 xenografts in mice. However,111In-DOTA-3A3 cleared more rapidly from blood than a size-matched control construct111In-DOTA-TAT, most likely due to sequestering of 3A3 by mErbB3, the murine counterpart of HER3. Repeated dosing and increase of injected protein dose decreased uptake of111In-DOTA-3A3 in mErbB3-expressing tissues. Encouragingly, growth of BxPC-3 xenografts in mice was delayed in an experimental (pilot-scale) therapy study using 3A3. We conclude that the 3A3 affibody format seems promising for treatment of HER3-overexpressing tumours.
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH-Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
authors.forename: Tarek Z
authors.initials: TZ
authors.lastname: Bass
authors.affiliation: Division of Molecular Imaging, Department of Medicinal Chemistry, Uppsala University, SE-751 83, Uppsala, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Rosestedt
authors.affiliation: Division of Molecular Imaging, Department of Medicinal Chemistry, Uppsala University, SE-751 83, Uppsala, Sweden.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Mitran
authors.affiliation: Affibody AB, SE-171 63 Stockholm, Solna, Sweden.|Department of Immunology, Genetics and Pathology, Uppsala University, SE-75285, Uppsala, Sweden.
authors.forename: Fredrik Y
authors.initials: FY
authors.lastname: Frejd
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH-Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
authors.forename: John
authors.initials: J
authors.lastname: Löfblom
authors.affiliation: Department of Immunology, Genetics and Pathology, Uppsala University, SE-75285, Uppsala, Sweden.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tolmachev
authors.affiliation: Division of Protein Technology, School of Biotechnology, KTH-Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Ståhl
authors.affiliation: Division of Molecular Imaging, Department of Medicinal Chemistry, Uppsala University, SE-751 83, Uppsala, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Orlova
mesh_terms: D000818:Animals; D000074322:Antineoplastic Agents, Immunological / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D002277:Carcinoma / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D064593:Heterografts; D006801:Humans; D051379:Mice; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D020893:Receptor, ErbB-3 / Q000037:antagonists & inhibitors*; D016896:Treatment Outcome
chemical_list: D000074322:Antineoplastic Agents, Immunological; C581292:ERBB3 protein, human; D020893:Receptor, ErbB-3