title: Increasing serum half-life and extending cholesterol lowering in vivo by engineering antibody with pH-sensitive binding to PCSK9.
abstract: Target-mediated clearance and high antigen load can hamper the efficacy and dosage of many antibodies. We show for the first time that the mouse, cynomolgus, and human cross-reactive, antagonistic anti-proprotein convertase substilisin kexin type 9 (PCSK9) antibodies J10 and the affinity-matured and humanized J16 exhibit target-mediated clearance, resulting in dose-dependent pharmacokinetic profiles. These antibodies prevent the degradation of low density lipoprotein receptor, thus lowering serum levels of LDL-cholesterol and potently reducing serum cholesterol in mice, and selectively reduce LDL-cholesterol in cynomolgus monkeys. In order to increase the pharmacokinetic and efficacy of this promising therapeutic for hypercholesterolemia, we engineered pH-sensitive binding to mouse, cynomolgus, and human PCSK9 into J16, resulting in J17. This antibody shows prolonged half-life and increased duration of cholesterol lowering in two species in vivo by binding to endogenous PCSK9 in mice and cynomolgus monkeys, respectively. The proposed mechanism of this pH-sensitive antibody is that it binds with high affinity to PCSK9 in the plasma at pH 7.4, whereas the antibody-antigen complex dissociates at the endosomal pH of 5.5-6.0 in order to escape from target-mediated degradation. Additionally, this enables the antibody to bind to another PCSK9 and therefore increase the antigen-binding cycles. Furthermore, we show that this effect is dependent on the neonatal Fc receptor, which rescues the dissociated antibody in the endosome from degradation. Engineered pH-sensitive antibodies may enable less frequent or lower dosing of antibodies hampered by target-mediated clearance and high antigen load.
authors.affiliation: Rinat-Pfizer Inc., South San Francisco, California 94080, USA.
authors.forename: Javier
authors.initials: J
authors.lastname: Chaparro-Riggers
authors.forename: Hong
authors.initials: H
authors.lastname: Liang
authors.forename: Rachel M
authors.initials: RM
authors.lastname: DeVay
authors.forename: Lanfang
authors.initials: L
authors.lastname: Bai
authors.forename: Janette E
authors.initials: JE
authors.lastname: Sutton
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Tao
authors.initials: T
authors.lastname: Geng
authors.forename: Kevin
authors.initials: K
authors.lastname: Lindquist
authors.forename: Meritxell Galindo
authors.initials: MG
authors.lastname: Casas
authors.forename: Leila M
authors.initials: LM
authors.lastname: Boustany
authors.forename: Colleen L
authors.initials: CL
authors.lastname: Brown
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Chabot
authors.forename: Bruce
authors.initials: B
authors.lastname: Gomes
authors.forename: Pamela
authors.initials: P
authors.lastname: Garzone
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossi
authors.forename: Pavel
authors.initials: P
authors.lastname: Strop
authors.forename: Dave
authors.initials: D
authors.lastname: Shelton
authors.forename: Jaume
authors.initials: J
authors.lastname: Pons
authors.forename: Arvind
authors.initials: A
authors.lastname: Rajpal
mesh_terms: D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000097:blood / Q000276:immunology* / Q000493:pharmacokinetics* / Q000494:pharmacology; D000924:Anticholesteremic Agents / Q000097:blood / Q000276:immunology / Q000493:pharmacokinetics* / Q000494:pharmacology*; D022801:Complementarity Determining Regions / Q000737:chemistry; D006207:Half-Life; D056945:Hep G2 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000378:metabolism; D008252:Macaca fascicularis; D008297:Male; D051379:Mice; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases / Q000276:immunology*; D015202:Protein Engineering; D011961:Receptors, Fc / Q000378:metabolism; D012697:Serine Endopeptidases / Q000276:immunology*
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000924:Anticholesteremic Agents; D022801:Complementarity Determining Regions; D011961:Receptors, Fc; C472125:PCSK9 protein, human; D000071449:Proprotein Convertase 9; D043484:Proprotein Convertases; D012697:Serine Endopeptidases