title: Identification and multidimensional optimization of an asymmetric bispecific IgG antibody mimicking the function of factor VIII cofactor activity.
abstract: In hemophilia A, routine prophylaxis with exogenous factor VIII (FVIII) requires frequent intravenous injections and can lead to the development of anti-FVIII alloantibodies (FVIII inhibitors). To overcome these drawbacks, we screened asymmetric bispecific IgG antibodies to factor IXa (FIXa) and factor X (FX), mimicking the FVIII cofactor function. Since the therapeutic potential of the lead bispecific antibody was marginal, FVIII-mimetic activity was improved by modifying its binding properties to FIXa and FX, and the pharmacokinetics was improved by engineering the charge properties of the variable region. Difficulties in manufacturing the bispecific antibody were overcome by identifying a common light chain for the anti-FIXa and anti-FX heavy chains through framework/complementarity determining region shuffling, and by pI engineering of the two heavy chains to facilitate ion exchange chromatographic purification of the bispecific antibody from the mixture of byproducts. Engineering to overcome low solubility and deamidation was also performed. The multidimensionally optimized bispecific antibody hBS910 exhibited potent FVIII-mimetic activity in human FVIII-deficient plasma, and had a half-life of 3 weeks and high subcutaneous bioavailability in cynomolgus monkeys. Importantly, the activity of hBS910 was not affected by FVIII inhibitors, while anti-hBS910 antibodies did not inhibit FVIII activity, allowing the use of hBS910 without considering the development or presence of FVIII inhibitors. Furthermore, hBS910 could be purified on a large manufacturing scale and formulated into a subcutaneously injectable liquid formulation for clinical use. These features of hBS910 enable routine prophylaxis by subcutaneous delivery at a long dosing interval without considering the development or presence of FVIII inhibitors. We expect that hBS910 (investigational drug name: ACE910) will provide significant benefit for severe hemophilia A patients.
authors.affiliation: Research Division, Chugai Pharmaceutical Co., Ltd., Gotemba, Shizuoka, Japan.
authors.forename: Zenjiro
authors.initials: Z
authors.lastname: Sampei
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Igawa
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Soeda
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Okuyama-Nishida
authors.forename: Chifumi
authors.initials: C
authors.lastname: Moriyama
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Wakabayashi
authors.forename: Eriko
authors.initials: E
authors.lastname: Tanaka
authors.forename: Atsushi
authors.initials: A
authors.lastname: Muto
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kojima
authors.forename: Takehisa
authors.initials: T
authors.lastname: Kitazawa
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Yoshihashi
authors.forename: Aya
authors.initials: A
authors.lastname: Harada
authors.forename: Miho
authors.initials: M
authors.lastname: Funaki
authors.forename: Kenta
authors.initials: K
authors.lastname: Haraya
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Tachibana
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Suzuki
authors.forename: Keiko
authors.initials: K
authors.lastname: Esaki
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nabuchi
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Hattori
mesh_terms: D018033:Antibodies, Bispecific / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005169:Factor VIII / Q000276:immunology / Q000493:pharmacokinetics / Q000502:physiology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007526:Isoelectric Point; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D018033:Antibodies, Bispecific; D000939:Epitopes; D007074:Immunoglobulin G; D005169:Factor VIII