2. Academic Validation
  3. MAA868, a novel FXI antibody with a unique binding mode, shows durable effects on markers of anticoagulation in humans

MAA868, a novel FXI antibody with a unique binding mode, shows durable effects on markers of anticoagulation in humans

  • Blood. 2019 Mar 28;133(13):1507-1516. doi: 10.1182/blood-2018-10-880849.
Alexander W Koch 1,  Nikolaus Schiering 2,  Samu Melkko 2,  Stefan Ewert 2,  Janeen Salter 3,  Yiming Zhang 3,  Peter McCormack 4,  Jianying Yu 1,  Xueming Huang 1,  Yu-Hsin Chiu 1,  Zhiping Chen 1,  Simone Schleeger 2,  Geraldine Horny 2,  Keith DiPetrillo 3,  Lionel Muller 2,  Andreas Hein 2,  Frederic Villard 2,  Meike Scharenberg 2,  Paul Ramage 2,  Ulrich Hassiepen 2,  Serge Côté 2,  Julie DeGagne 2,  Carsten Krantz 2,  Jörg Eder 2,  Brian Stoll 1,  Kenneth Kulmatycki 1,  David L Feldman 1,  Peter Hoffmann 5,  Craig T Basson 1,  Robert J A Frost 2,  Yasser Khder 2
Affiliations

Affiliations

  • 1 Novartis Institutes for BioMedical Research, Cambridge, MA.
  • 2 Novartis Institutes for BioMedical Research, Basel, Switzerland.
  • 3 Novartis Pharmaceuticals Corporation, East Hanover, NJ.
  • 4 Novartis Pharma AG, Basel, Switzerland; and.
  • 5 Novartis Institutes for BioMedical Research, East Hanover, NJ.
PMID: 30692123 DOI: 10.1182/blood-2018-10-880849
Abstract

A large unmet medical need exists for safer antithrombotic drugs because all currently approved anticoagulant agents interfere with hemostasis, leading to an increased risk of bleeding. Genetic and pharmacologic evidence in humans and Animals suggests that reducing factor XI (FXI) levels has the potential to effectively prevent and treat thrombosis with a minimal risk of bleeding. We generated a fully human antibody (MAA868) that binds the catalytic domain of both FXI (zymogen) and activated FXI. Our structural studies show that MAA868 traps FXI and activated FXI in an inactive, zymogen-like conformation, explaining its equally high binding affinity for both forms of the Enzyme. This binding mode allows the Enzyme to be neutralized before entering the coagulation process, revealing a particularly attractive anticoagulant profile of the antibody. MAA868 exhibited favorable anticoagulant activity in mice with a dose-dependent protection from carotid occlusion in a ferric chloride-induced thrombosis model. MAA868 also caused robust and sustained anticoagulant activity in cynomolgus monkeys as assessed by activated partial thromboplastin time without any evidence of bleeding. Based on these preclinical findings, we conducted a first-in-human study in healthy subjects and showed that single subcutaneous doses of MAA868 were safe and well tolerated. MAA868 resulted in dose- and time-dependent robust and sustained prolongation of activated partial thromboplastin time and FXI suppression for up to 4 weeks or longer, supporting further clinical investigation as a potential once-monthly subcutaneous anticoagulant therapy.

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