INTRODUCTION/AIMS: Prospective, randomized, controlled trials of intravenous immunoglobulin (IVIG) maintenance therapy in myasthenia gravis (MG) are lacking. In this trial, we evaluated the safety and efficacy of caprylate/chromatography-purified IVIG; (IGIV-C) in patients with generalized MG undergoing standard care. METHODS: Sixty-two patients enrolled in this phase 2, multicenter, international, randomized trial (1:1 IGIV-C [2 g/kg loading dose; 1 g/kg every 3 weeks through week 21] or placebo). Efficacy was assessed by changes in Quantitative MG (QMG) score at week 24 versus baseline (primary endpoint) and percentage of patients with clinical improvement in QMG, MG Composite (MGC), and MG-Activities of Daily Living (MG-ADL) scores (secondary endpoints). Safety assessments reported all adverse events (AEs). RESULTS: The change in QMG at 24 weeks was -5.1 for IGIV-C and -3.1 for placebo (p = .187). Seventy percent of patients in the IGIV-C group had improvement in MG-ADL (≥2-point decrease) versus 40.6% in the placebo group (p = .025). Patients showing clinical improvement in QMG and MGC (≥3-point decrease) were 70.0% for IGIV-C versus 59.4% for placebo (p = .442) and 60.0% for IGIV-C versus 53.1% for placebo (p = .610). IGIV-C was well tolerated; serious AEs were similar between arms. Three of four MG exacerbations requiring hospitalizations occurred in the IGIV-C arm with one death. DISCUSSION: Several efficacy parameters showed numerical results greater than those seen in the placebo group. This was a small study and may have been underpowered to see significant differences. Additional studies may be warranted to fully determine the efficacy of IVIG maintenance therapy in MG.

3 Miejskie Centrum Medyczne im Dr Karola Jonschera w Łodzi Lodz Poland

Centrum Neurologii Klinicznej Krakow Poland

Department of Neurology Albert Szent Györgyi Clinical Center University of Szeged Szeged Hungary

Department of Neurology Flór Ferenc County Hospital Kistarcsa Hungary

Department of Neurology Hospital of Lithuanian University of Health Sciences Kaunas Clinics Kaunas Lithuania

Department of Neurology Rutgers New Jersey Medical School Newark New Jersey USA

Department of Neurology The Ohio State University Columbus Ohio USA

Department of Neurology Thomas Jefferson University Philadelphia Pennsylvania USA

Department of Neurology University Clinic Dresden Technische Universität Dresden Dresden Germany

Department of Neurology University Hospital Brno and Faculty of Medicine Masaryk University Brno Czech Republic

Department of Neurology University of Kansas Medical Center Kansas City Kansas USA

Department of Neurology University of South Florida Morsani College of Medicine Tampa Florida USA

East Tallinn Central Hospital Tallinn Estonia

Fakultni Nemocnice Ostrava Neurologicka Klinika Ostrava Poruba Czech Republic

Grifols Bioscience Research Group Research Triangle Park North Carolina USA

Grifols Bioscience Research Group Sant Cugat Spain

Honor Health Neurology Scottsdale Arizona USA

Indiana School of Medicine Indianapolis Indiana USA

Jahn Ferenc Del pesti Korhaz es Rendelointezet Neurologiai Osztaly Budapest Hungary

London Health Sciences Centre and Western University London Ontario Canada

National and Kapodistrian University of Athens Athens Greece

Neurology EMG Laboratory Augusta University Augusta Georgia USA

Toronto General Hospital Toronto Ontario Canada

Universitaetsklinikum Hamburg Eppendorf Klinik und Poliklinik fuer Neurologie Neurologische Studienzentrale Hamburg Germany

University of California Irvine Orange California USA

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