The Food and Drug Administration (FDA) has accepted for review the Biologics License Application (BLA) for efgartigimod (ARG-113; argenx) for the treatment of generalized myasthenia gravis.
Efgartigimod is an Fc receptor antagonist designed to reduce immunoglobulin G (IgG) antibody levels and block the IgG recycling process. The application is supported by data from the multicenter, randomized, double-blind phase 3 ADAPT trial (ClinicalTrials.gov: NCT03669588) that compared the efficacy and safety of efgartigimod to placebo administered as an intravenous infusion in 167 adults with generalized myasthenia gravis. The primary end point was the percentage of responders on the Myasthenia Gravis Activities of Daily Living (MG-ADL) score among acetylcholine receptor-antibody positive (AChR-Ab+) generalized myasthenia gravis patients. Responders were defined as having at least a 2-point improvement on the MG-ADL score for at least 4 consecutive weeks.
Findings from the trial showed that a significantly greater proportion of AChR-Ab+ patients treated with efgartigimod met the primary end point compared with placebo (67.7% vs 29.7%, respectively; P <.0001). Additionally, a greater proportion of efgartigimod-treated AChR-Ab+ patients achieved minimal symptom expression, defined as a MG-ADL scores of 0 (symptom free) or 1, and responded on the Quantitative Myasthenia Gravis score, compared with placebo.
The Company is currently evaluating the long-term safety and tolerability of efgartigimod in the 3-year, open-label extension ADAPT+ study (ClinicalTrials.gov: NCT03770403) in 118 patients who completed the ADAPT trial.
A Prescription Drug User Fee Act (PDUFA) target date of December 17, 2021 has been set for this application.
argenx announces FDA acceptance of BLA filing for efgartigimod for the treatment of generalized myasthenia gravis. [press release]. Breda, Netherlands: argenx; March 2, 2021.