argenx Advances Clinical Development of Efgartigimod SC in Idiopathic Inflammatory Myopathies

Core Insights - The Phase 2 data supports the proof-of-concept for efgartigimod SC in treating myositis, leading to the decision to continue development in the Phase 3 ALKIVIA study across all three myositis subtypes [1][2] - Efgartigimod SC has the potential to be the first targeted treatment for myositis patients with limited existing options [1][2] Study Design - The ALKIVIA study is a randomized, double-blind, placebo-controlled, multicenter Phase 2/3 trial involving 240 patients, focusing on idiopathic inflammatory myopathies (IIM) across three subtypes: IMNM, ASyS, and DM [3] - The primary endpoint is the mean total improvement score (TIS) at 24 weeks for Phase 2 and 52 weeks for Phase 3, with key secondary endpoints including response rates and quality of life measures [3] Efficacy and Safety - The Phase 2 portion of the ALKIVIA study met its primary endpoint, showing a statistically significant treatment effect in mean TIS at Week 24, with improvements across all six core set measures compared to placebo [2][3] - The safety and tolerability profile of efgartigimod SC was consistent with previous clinical trials [2] Background on Myositis - Idiopathic inflammatory myopathies (myositis) are rare autoimmune diseases that can severely impact muscle function and quality of life, affecting multiple organs [4] - The classification of myositis has evolved, with new subtypes like IMNM and ASyS emerging alongside traditional classifications [4][5] About Efgartigimod SC - Efgartigimod SC is a human IgG1 antibody fragment designed to reduce pathogenic IgG antibodies by blocking the IgG recycling process, currently evaluated in over 15 severe autoimmune diseases [6] - It is the first approved FcRn blocker globally, marketed under various names for conditions like generalized myasthenia gravis and chronic inflammatory demyelinating polyneuropathy [6] Company Overview - Argenx is a global immunology company focused on developing novel antibody-based medicines for severe autoimmune diseases, partnering with academic researchers to translate immunology breakthroughs into effective treatments [7]