P.034 Minimal symptom expression following treatment with efgartigimod in patients with Generalized Myasthenia Gravis

Background: Efgartigimod is a human IgG1 antibody Fc-fragment that reduces IgG levels through FcRn blockade. A key efficacy indicator in the treatment of autoantibody-mediated generalized myasthenia gravis (gMG) improvement MG-ADL score. Methods: The ADAPT phase 3 trial evaluated safety and efgartigimod patients with gMG, including reaching maintaining minimal symptom expression (MSE; defined as an total score 0 or 1). Results: 167 (AChR-Ab+, n=129; AChR-Ab-, n=38) were randomized to receive cycles 4 weekly infusions placebo. Significantly more AChR-Ab+ efgartigimod-treated achieved MSE during cycle 1 compared placebo-treated (40.0% [n=26/65] vs 11.1% [n=7/63; P <0.0001]). In 2, 31.4% (n=16/51) cohort none placebo cohort. improved by ≥6 points 56.9% 20.6% 1. Most week cycle, paralleling early reduction levels, duration ranged from ≥10 weeks. Adverse events predominantly mild moderate. Conclusions: resulted gMG achieving both clinically meaningful improvements.