A Study to Assess the Efficacy and Safety of Efgartigimod PH20 SC in Adults With Systemic Sclerosis

Who May Qualify: - Is aged ≥18 years and the local legal age of consent for clinical studies - Has diffuse or limited SSc diagnosis and fulfills the 2013 ACR/EULAR classification criteria - Has a positive antinuclear antibodies (ANA) test result at the central laboratory with titer of at least 1:160 - Has a Health Assessment Questionnaire-Disability Index (HAQ-DI) score of at least 0.5 OR a Patient Global Assessment (PGA) score of at least 3 - Has a modified Rodnan Skin Score (mRSS) score between 15 and 35 - The participant is anti-RNA polymerase III autoantibody negative at central laboratory and had the first non-Raynaud's phenomenon manifestation less than 5 years before screening or the participant is anti-RNA polymerase III autoantibody positive at central laboratory and had the first non-Raynaud's phenomenon manifestation less than 2 years before screening - Has uninvolved or mildly thickened skin area in at least 1 injection site Who Should NOT Join This Trial: - Isolated anticentromere antibodies (ACA) seropositivity at the central laboratory - Significant Pulmonary Arterial Hypertension - Severe digital vasculopathy within the past 3 months - Skin thickening due to scleroderma mimics or localized scleroderma - Scleroderma renal crisis within the past 6 months of participating to the study - Another rheumatic autoimmune conditions (where your immune system attacks your own body), except for secondary Sjögren's syndrome or fibromyalgia Always talk to your doctor about whether this trial is right for you.