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    Poster Networking

    Platelet Disorders, von Willebrand Disease and Thrombotic Microangiopathies

    Poster Networking Session

    PB1334 - Safety Profile of Efgartigimod from Clinical Trials in Participants with Immunoglobulin G-Mediated Autoimmune Diseases

    Tuesday, June 27, 2023
    18:30 – 19:30 ET
    Room: Exhibition

      Presenting Author(s)

    • Michelle Sholzberg, MDCM, FRCPC, MSc., MDCM, FRCPC, MSc

      Head, Division of Hematology-Oncology
      Departments of Medicine, and Laboratory Medicine and Pathobiology, Li Ka Shing Knowledge Institute, University of Toronto, Toronto, ON, Canada
      Toronto, Ontario, Canada

      • Co-Author(s)

    • KG

      Kelly Gwathmey

      Division Chair, Assistant Professor
      Department of Neurology, Virginia Commonwealth University
      Richmond, Virginia, United States

    • Catherine M. Broome, PhD

      Clinician
      Department of Medicine, Georgetown University
      Washington, DC, District of Columbia, United States

    • MG

      Matthias Goebeler

      Professor
      Department of Dermatology, Venereology and Allergology, University Hospital Wϋrzburg
      Wϋrzburg, Baden-Wurttemberg, Germany

    • HM

      Hiroyuki Murai

      Professor
      Department of Neurology, School of Medicine, International University of Health and Welfare
      Narita, Chiba, Japan

    • ZB

      Zsuzsanna Bata-Csörgo

      Professor
      Department of Dermatology and Allergology, University of Szeged
      Szeged, Csongrad, Hungary

    • AN

      Adrian Newland

      Professor, Consultant Haematologist
      Centre for Haematology, Barts and the London School of Medicine & Dentistry, Queen Mary University of London
      London, England, United Kingdom

    • PU

      Peter Ulrichts

      Chief Scientific Officer
      argenx
      Ghent, Oost-Vlaanderen, Belgium

    • RK

      Rene Kerstens

      Biostatistical Consultant
      argenx
      Ghent, Oost-Vlaanderen, Belgium

    • JG

      Jeffrey T. Guptill

      Clinical Specialist
      argenx
      Ghent, Oost-Vlaanderen, Belgium

    • SA

      Sofiane Agha

      Senior Director- Global Safety Lead
      argenx
      Ghent, Oost-Vlaanderen, Belgium

    • MJ

      Ming Jiang

      Global Patient Safety Lead
      argenx
      Ghent, Oost-Vlaanderen, Belgium

    • JH

      James F. Howard, Jr.

      Professor of Neurology, Medicine & Allied Health
      Department of Neurology, The University of North Carolina at Chapel Hill
      Chapel Hill, North Carolina, United States

    Background: Efgartigimod is a first-in-class, human immunoglobulin-G (IgG) Fc fragment that inhibits the neonatal Fc receptor (FcRn) and outcompetes endogenous IgG binding. FcRn inhibition by efgartigimod is a rational therapeutic option for IgG-mediated autoimmune disorders, including immune thrombocytopenia (ITP).

    Aims: To determine the safety profile of efgartigimod for a variety of IgG-mediated autoimmune disorders, including ITP.

    Methods: Intravenous efgartigimod safety was assessed in a phase 3 (ADVANCE) trial in ITP. It was also evaluated in generalized myasthenia gravis (gMG) in phase 2 and 3 (ADAPT) trials and a 3-year open-label extension (ADAPT+) along with an open-label phase 2 trial in pemphigus. Varying dosing regimens of efgartigimod (10-25 mg/kg) were used, including cyclical (gMG) and continuous weekly dosing (ITP, pemphigus).

    Results: Across all indications and doses studied, efgartigimod demonstrated a consistent safety profile, with comparable treatment emergent adverse event (TEAE) rates to placebo (ADVANCE 93.0% efgartigimod vs. 95.6% placebo; ADAPT 77.4% efgartigimod vs. 84.3% placebo; 85% of participants in open label pemphigus study). Most TEAEs across studies were mild to moderate in severity. Discontinuation rates due to adverse events were low across studies (3.5% efgartigimod vs. 2.2% placebo in ADVANCE; 3.6% efgartigimod vs. 3.6% placebo in ADAPT; 3% in pemphigus). No increase in TEAE incidence rates or infections with repeated efgartigimod cycles (up to 19) in ADAPT+ was observed. In ADVANCE, no thromboembolic TEAEs were reported. Efgartigimod did not impair participant ability to generate new specific IgG responses to non-live vaccines, regardless of the timing of vaccinations however, there were transient reductions in specific IgG titers observed.

    Conclusion(s): Efgartigimod was generally well tolerated across indications and doses studied. Most TEAEs, including infections, were mild or moderate in severity and did not increase in frequency with recurrent dosing. Non-live vaccine responsiveness was preserved. There were no thromboembolic events in those treated for ITP.

    Funded by argenx BVBA.