argenx Announces Positive Topline Results from Phase 3 ADAPT Trial of Efgartigimod in Patients with Generalized Myasthenia Gravis

Regulated information – Inside information

• Trial met primary endpoint (p ˂0.0001)
   
• Well-tolerated; safety profile comparable to placebo
   
• Biologics License Application on track to be submitted to U.S. Food and Drug Administration by end of 2020
   
• Conference call scheduled for today, May 26, 2020 at 8:30 a.m. EDT (2:30 p.m. CEST)

May 26, 2020

Breda, the Netherlands / Ghent, Belgium – argenx (Euronext & Nasdaq: ARGX), a global immunology company committed to improving the lives of people suffering from severe autoimmune diseases and cancer, today announced positive topline data from the pivotal ADAPT trial of efgartigimod. ADAPT met its primary endpoint defined as percentage of responders on the Myasthenia Gravis Activities of Daily Living (MG-ADL) score among acetylcholine receptor-antibody positive (AChR-Ab+) generalized myasthenia gravis (gMG) patients. Responders are defined as having at least a two-point improvement on the MG-ADL score for at least four consecutive weeks. Based on these results, argenx plans to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) by the end of 2020.

Highlights of topline ADAPT data

• 67.7% of AChR-Ab+ patients treated with efgartigimod achieved the primary endpoint compared with 29.7% on placebo (p<0.0001).
• 63.1% of AChR-Ab+ patients responded to efgartigimod compared with 14.1% on placebo on the Quantitative Myasthenia Gravis (QMG) score (p<0.0001); responder defined as having at least a three-point improvement on the QMG score for at least four consecutive weeks.
• 40.0% of efgartigimod-treated AChR-Ab+ patients achieved minimal symptom expression defined as MG-ADL scores of 0 (symptom free) or 1, compared to 11.1% treated with placebo.
• Efgartigimod was well-tolerated with a safety profile that was comparable to placebo.
  
  

“The efgartigimod data showed rapid and robust responses in people with gMG, as well as a favorable tolerability profile,” said James F. Howard Jr., M.D., Professor of Neurology (Neuromuscular Disease), Medicine and Allied Health, Department of Neurology, The University of North Carolina at Chapel Hill School of Medicine and principal investigator for the ADAPT trial. “Patients with this devastating disease can experience chronic and potentially life-threatening muscle weakness that has a major impact on their quality of life, and more treatment options are needed. These data are very encouraging as they show efgartigimod has potential to make a meaningful impact on daily living activities, and we are hopeful they will lead to a new treatment being available for the gMG community.”