July 2019
Volume 60, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2019
Development of anti-drug antibodies following intravitreal administration of anti-C3b Fabs in cynomolgus monkeys and rabbits
Author Affiliations & Notes
  • Michael Twarog
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Steve Louie
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Mark Milton
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Ana Carrion
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Omar Delgado
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Maura Crowley
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Natasha Buchanan
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Shawn Hanks
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • John T Demirs
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Chad E Bigelow
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Stephen H Poor
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Yong-in Kim
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Sha-Mei Liao
    Novartis Institutes for Biomedical Research, Inc., Cambridge, Massachusetts, United States
  • Footnotes
    Commercial Relationships   Michael Twarog, Novartis Institutes for Biomedical Research, Inc (E); Steve Louie, Novartis Institutes for Biomedical Research, Inc (E); Mark Milton, Novartis Institutes for Biomedical Research, Inc (E); Ana Carrion, Novartis Institutes for Biomedical Research, Inc (E); Omar Delgado, Novartis Institutes for Biomedical Research, Inc (E); Maura Crowley, Novartis Institutes for Biomedical Research, Inc (E); Natasha Buchanan, Novartis Institutes for Biomedical Research, Inc (E); Shawn Hanks, Novartis Institutes for Biomedical Research, Inc (E); John Demirs, Novartis Institutes for Biomedical Research, Inc (E); Chad Bigelow, Novartis Institutes for Biomedical Research, Inc (E); Stephen Poor, Novartis Institutes for Biomedical Research, Inc (E); Yong-in Kim, Novartis Institutes for Biomedical Research, Inc (E); Sha-Mei Liao, Novartis Institutes for Biomedical Research, Inc (E)
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 4014. doi:https://doi.org/
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      Michael Twarog, Steve Louie, Mark Milton, Ana Carrion, Omar Delgado, Maura Crowley, Natasha Buchanan, Shawn Hanks, John T Demirs, Chad E Bigelow, Stephen H Poor, Yong-in Kim, Sha-Mei Liao; Development of anti-drug antibodies following intravitreal administration of anti-C3b Fabs in cynomolgus monkeys and rabbits. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4014. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Antibodies were designed to target neo-epitopes on C3b, in order to inhibit the C3/C5 convertases of the complement pathway. In vivo effects of the antibodies were characterized in cynomolgus (cyno) monkeys and rabbits after intravitreal (IVT) administration.

Methods : Human Fab antibodies (NVS1 and NVS2), which are specific for C3b, were generated using phage-display technology. The selection criteria was based on assessment of potency in complement functional assays, affinity, and selectivity for C3b. Anti-C3b antibodies (50μL/eye) were intravitreally injected into cyno monkeys (n=4; 1 and 5 mg/eye) and rabbits (n=12; 0.5 and 5 mg/eye). Eyes were analyzed by OCT, cytospin, histology, and measured for complement activation and cytokine production.

Results : Anti-C3b antibodies bound neo-epitopes found on C3b/iC3b/C3c with high affinity (human: 4-20pM, cyno: 45-125pM), did not cross-react with C3 or C5, and were potent inhibitors of the alternative complement pathway by blocking binding to Factor B. A single IVT administration of anti-C3b Fabs at 5 mg/eye produced severe inflammation in cyno monkeys and rabbits. Anti-drug antibodies (ADA) were detected in the serum of all dosed animals 14 days after injection. Animals dosed at 5 mg/eye also exhibited hyper-reflective features in the vitreous, retinal degeneration, inflammatory cell infiltrates, cytokine production, and intraocular complement activation. Severity of the ocular toxicity correlated with high titers of ADA in the vitreous. Notably, none of the eye pathologies, including ocular ADA, were observed in the untreated contralateral eye. In vitro, serum from monkeys with high ADA titers was able to initiate classical pathway activation in response to drug.

Conclusions : Antibodies selective for C3b were potent in vitro inhibitors of the alternative pathway of complement. However, in vivo administration of Fabs resulted in severe intraocular complement activation. The binding of the C3b:Fab complex to antigen presenting cells may have resulted in the generation of an immune response against the Fabs. Binding of anti-drug antibodies to C3b:Fab complexes resulted in activation of complement through the classical pathway, and contributed to the retinal inflammation observed in vivo.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

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