title: A novel platform for engineering blood-brain barrier-crossing bispecific biologics.
abstract: The blood-brain barrier (BBB) prevents the access of therapeutic antibodies to central nervous system (CNS) targets. The engineering of bispecific antibodies in which a therapeutic "arm" is combined with a BBB-transcytosing arm can significantly enhance their brain delivery. The BBB-permeable single-domain antibody FC5 was previously isolated by phenotypic panning of a naive llama single-domain antibody phage display library. In this study, FC5 was engineered as a mono- and bivalent fusion with the human Fc domain to optimize it as a modular brain delivery platform. In vitro studies demonstrated that the bivalent fusion of FC5 with Fc increased the rate of transcytosis (Papp) across brain endothelial monolayer by 25% compared with monovalent fusion. Up to a 30-fold enhanced apparent brain exposure (derived from serum and cerebrospinal fluid pharmacokinetic profiles) of FC5- compared with control domain antibody-Fc fusions after systemic dosing in rats was observed. Systemic pharmacological potency was evaluated in the Hargreaves model of inflammatory pain using the BBB-impermeable neuropeptides dalargin and neuropeptide Y chemically conjugated with FC5-Fc fusion proteins. Improved serum pharmacokinetics of Fc-fused FC5 contributed to a 60-fold increase in pharmacological potency compared with the single-domain version of FC5; bivalent and monovalent FC5 fusions with Fc exhibited similar systemic pharmacological potency. The study demonstrates that modular incorporation of FC5 as the BBB-carrier arm in bispecific antibodies or antibody-drug conjugates offers an avenue to develop pharmacologically active biotherapeutics for CNS indications.
authors: Biogen Idec, Inc., Cambridge, Massachusetts, USA; and danica.stanimirovic@nrc-cnrc.gc.ca graham.farrington@biogenidec.com.
authors: Graham K
authors: GK
authors: Farrington
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Nadia
authors: N
authors: Caram-Salas
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Arsalan S
authors: AS
authors: Haqqani
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Eric
authors: E
authors: Brunette
authors: Biogen Idec, Inc., Cambridge, Massachusetts, USA; and.
authors: John
authors: J
authors: Eldredge
authors: Biogen Idec, Inc., Cambridge, Massachusetts, USA; and.
authors: Blake
authors: B
authors: Pepinsky
authors: Biogen Idec, Inc., Cambridge, Massachusetts, USA; and.
authors: Giovanna
authors: G
authors: Antognetti
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Ewa
authors: E
authors: Baumann
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Wen
authors: W
authors: Ding
authors: Biogen Idec, Inc., Cambridge, Massachusetts, USA; and.
authors: Ellen
authors: E
authors: Garber
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Susan
authors: S
authors: Jiang
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Christie
authors: C
authors: Delaney
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors: Eve
authors: E
authors: Boileau
authors: Biogen Idec, Inc., Cambridge, Massachusetts, USA; and.
authors: William P
authors: WP
authors: Sisk
authors: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada danica.stanimirovic@nrc-cnrc.gc.ca graham.farrington@biogenidec.com.
authors: Danica B
authors: DB
authors: Stanimirovic
mesh_terms: D000818:Animals; D018033:Antibodies, Bispecific / Q000276:immunology / Q000378:metabolism*; D001688:Biological Products / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D001812:Blood-Brain Barrier / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D006801:Humans; D018796:Immunoconjugates / Q000378:metabolism; D008297:Male; D015202:Protein Engineering / Q000379:methods; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D018033:Antibodies, Bispecific; D001688:Biological Products; D018796:Immunoconjugates; D011993:Recombinant Fusion Proteins
keywords: drug delivery; neuropeptides; single-domain antibody