title: Brain penetration, target engagement, and disposition of the blood-brain barrier-crossing bispecific antibody antagonist of metabotropic glutamate receptor type 1.
abstract: Receptor mediated transcytosis harnessing the cellular uptake and transport of natural ligands across the blood-brain barrier (BBB) has been identified as a means for antibody delivery to the CNS. In this study, we characterized bispecific antibodies in which a BBB-crossing antibody fragment FC5 was used as a BBB carrier. Cargo antibodies were either a high-affinity, selective antibody antagonist of the metabotropic glutamate receptor-1 (BBB-mGluR1), a widely abundant CNS target, or an IgG that does not bind the CNS target (BBB-NiP). Both BBB-NiP and BBB-mGluR1 demonstrated a similar 20-fold enhanced rate of transcytosis across an in vitro BBB model compared with mGluR1 IgG fused to a control antibody fragment. All 3 bispecific antibodies exhibited identical pharmacokinetics in vivo Comparative assessment of BBB-NiP and BBB-mGluR1 revealed that, whereas their serum pharmacokinetics and BBB penetration were identical, their central disposition (brain levels) and elimination (cerebrospinal fluid levels) were widely different, due to central target-mediated removal of the mGluR1-engaging antibody. Central mGluR1 target engagement after systemic administration was demonstrated by a dose-dependent inhibition of mGluR-1-mediated thermal hyperalgesia and by colocalization of the antibody with thalamic neurons involved in mGluR1-mediated pain processing. We demonstrate the feasibility of targeting central G-protein-coupled receptors using a BBB-crossing bispecific antibody approach and emerging principles that govern brain distribution and disposition of these antibodies. These data will be important for designing safe and selective CNS antibody therapeutics.-Webster, C. I., Caram-Salas, N., Haqqani, A. S., Thom, G., Brown, L., Rennie, K., Yogi, A., Costain, W., Brunette, E., Stanimirovic, D. B. Brain penetration, target engagement, and disposition of the blood-brain barrier-crossing bispecific antibody antagonist of metabotropic glutamate receptor type 1.
authors.affiliation: Antibody Discovery and Protein Engineering, MedImmune, Cambridge, United Kingdom; websterc@medimmune.com.
authors.forename: Carl I
authors.initials: CI
authors.lastname: Webster
authors.affiliation: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors.forename: Nadia
authors.initials: N
authors.lastname: Caram-Salas
authors.affiliation: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors.forename: Arsalan S
authors.initials: AS
authors.lastname: Haqqani
authors.affiliation: Antibody Discovery and Protein Engineering, MedImmune, Cambridge, United Kingdom;
authors.forename: George
authors.initials: G
authors.lastname: Thom
authors.affiliation: Translational Sciences, MedImmune, Cambridge, United Kingdom; and.
authors.forename: Lee
authors.initials: L
authors.lastname: Brown
authors.affiliation: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors.forename: Kerry
authors.initials: K
authors.lastname: Rennie
authors.affiliation: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Yogi
authors.affiliation: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors.forename: Willard
authors.initials: W
authors.lastname: Costain
authors.affiliation: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Brunette
authors.affiliation: Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada.
authors.forename: Danica B
authors.initials: DB
authors.lastname: Stanimirovic
mesh_terms: D000700:Analgesics; D000818:Animals; D018033:Antibodies, Bispecific / Q000494:pharmacology*; D001688:Biological Products / Q000378:metabolism; D001692:Biological Transport; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D000071194:Camelidae; D002462:Cell Membrane; D057809:HEK293 Cells; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D018796:Immunoconjugates / Q000378:metabolism; D007074:Immunoglobulin G / Q000276:immunology; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D015202:Protein Engineering / Q000379:methods; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000700:Analgesics; D018033:Antibodies, Bispecific; D001688:Biological Products; D018796:Immunoconjugates; D007074:Immunoglobulin G; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1
keywords: brain endothelial cells; mass spectrometry; pain; receptor-mediated transcytosis