argenx Advances Clinical Development of ARGX-119 in Congenital Myasthenic Syndromes

Core Insights - argenx SE plans to advance the clinical development of ARGX-119, a first-in-class agonist antibody targeting muscle-specific kinase (MuSK), to a registrational study in patients with congenital myasthenic syndromes (CMS) based on favorable Phase 1b study results [1][4] - The Phase 1b study demonstrated a favorable safety profile and consistent functional improvement across multiple efficacy measures, including the Six-Minute Walk Test (6MWT) and Myasthenia Gravis Activities of Daily Living (MG-ADL) score [4][6] Company Overview - argenx is a global immunology company focused on improving the lives of individuals with severe autoimmune diseases through innovative antibody-based medicines [9] - The company utilizes a collaborative discovery model, the Immunology Innovation Program (IIP), to develop novel therapies, with ARGX-119 being the sixth molecule to show proof-of-concept [3][9] Clinical Study Details - The Phase 1b study was a multicenter, randomized, double-blinded, placebo-controlled trial assessing the safety, tolerability, pharmacokinetics, immunogenicity, and preliminary efficacy of ARGX-119 in DOK7-CMS patients [5] - The study included a 12-week treatment period and a follow-up period of nearly seven months, with participants randomized in a 4:1 ratio to receive either ARGX-119 or placebo [5] Disease Context - Congenital Myasthenic Syndromes (CMS) are ultra-rare neuromuscular disorders characterized by early onset and muscle weakness, with DOK7 variations accounting for approximately 24% of CMS cases [6] - The prevalence of CMS is estimated at 5 per million, with DOK7-CMS estimated at 1.2 per million, and there are currently no approved treatments available [6]