The purpose of this study is to measure the long-term safety and tolerability of efgartigimod PH20 SC in adult participants with IIM who previously participated in ARGX-113-2007. Secondary objectives include efficacy measures of efgartigimod PH20 SC in participants with IIM.
A Phase 3, Single-Arm, Multicenter, Open-label Extension of Study ARGX-113-2007 to Investigate the Long-term Safety, Tolerability, and Efficacy of Efgartigimod PH20 SC in Participants Aged 18 Years and Older With Active Idiopathic Inflammatory Myopathy