May 26, 2020 - Breda, the Netherlands / Ghent, Belgium
- 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
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.”
“With the ADAPT trial, we set out to evaluate efgartigimod’s ability to redefine the treatment paradigm for people living with gMG. The data showed that efgartigimod drove fast and deep responses, including in a proportion of patients who achieved minimal or no symptoms after treatment. In addition, we saw responses that lasted beyond eight or 12 weeks, supporting our plans to offer individualized dosing schedules that are purpose-fit to the variability in disease course that gMG patients experience,” commented Wim Parys, M.D., Chief Medical Officer of argenx. “Based on these data, we intend to submit a BLA for efgartigimod to the FDA before the end of the year, taking us one step closer to potentially making efgartigimod available to patients in 2021. All of us at argenx want to thank the patients and healthcare providers who participated in the ADAPT trial. ADAPT is the first pivotal trial of efgartigimod and these data further our confidence in its broad opportunity in other severe, IgG-mediated autoimmune diseases.”
Additional ADAPT results, including secondary endpoints and prespecified analyses
In the ADAPT trial, the secondary endpoints listed below also demonstrated statistically significant differences in the efgartigimod arm for AChR-Ab+ patients, unless otherwise noted, compared to placebo:
- MG-ADL responders in the overall population, including both AChR-Ab+ and AChR-antibody negative patients (p<0.0001).
- Time on trial in clinically meaningful improvement (MG-ADL improvement ≥2) (p=0.0001).
- Fast onset of response on MG-ADL score (onset observed in first two weeks) (p=0.0004).
- Time to qualify for retreatment endpoint did not meet statistical significance.
- In AChR-Ab+ patients who met the primary endpoint, the majority showed a sustained response, including 88.6% who achieved a response for at least six weeks, 56.8% for at least eight weeks and 34.1% for at least 12 weeks.
Of AChR-Ab+ patients who received a second treatment cycle, 70.6% were MG-ADL responders compared to 25.6% of placebo patients.
90% of patients enrolled in the ADAPT trial continued to the ADAPT-Plus open-label extension study.
Percentage of efgartigimod responders on the MG-ADL score in the AChR-antibody negative patient population was consistent with the AChR-Ab+ patient population, but a greater placebo response was observed in this cohort.
MG is a rare and chronic autoimmune disease where IgG antibodies disrupt communication between nerves and muscles, causing debilitating and potentially life-threatening muscle weakness. More than 85% of people with MG progress to generalized MG (gMG) within 18 months, where muscles throughout the body may be affected, resulting in extreme fatigue and difficulties with facial expression, speech, swallowing and mobility. In more life-threatening cases, MG can affect the muscles responsible for breathing. Patients with confirmed AChR antibodies account for 80-90% of the total gMG population. There are approximately 65,000 people in the United States and 20,000 people in Japan living with the disease.
« back to overview