Real-World experience with efgartigimod in patients with myasthenia gravis

Abstract

Recommendations for the treatment of myasthenia gravis (MG) have been difficult to develop because of limited evidence from large randomized controlled trials. New drugs and treatment approaches have recently been shown to be effective in phase 3 studies in seropositive generalized (g) MG. One such drug is efgartigimod, a human-Fc-fragment of IgG1, with a high affinity for the endosomal FcRn. We conducted a multicenter study to evaluate the real-world clinical and safety effects of efgartigimod in 22 gMG patients. We evaluated the strategies for the timing of re-treatment with it. The participants received a total of 59 efgartigimod -treatment cycles. The median number of cycles was 2 (range 1-6). Twenty patients (86.3%) improved by at least 2 MG-ADL points after the first treatment cycle. The median MG-ADL score at baseline was 6.5 (range: 3-17) and 2.5 (range: 0-9) post-treatment (p < 0.001). A consistent improvement of at least 2 points in the MG-ADL score after each cycle occurs in 18 patients. The effect duration of the treatment was usually between 4 and 12 weeks. Two major clinical patterns of treatment response were found. Treatment with efgartigimod was also associated with significant reductions of prednisone doses Overall, the treatment was safe and associated with only minor adverse events. The single fatality was apparently due tosevere respiratory failure. We found that efgartigimod is clinically effective, may be used as a steroid sparing agent and is generally safe for gMG patients. We recommend a personalized preventive treatment approach until clinical stabilization, followed by discontinuation and periodic evaluations.

Keywords: Efgartigimod; Generalized myasthenia gravis; MG-ADL; Prednisone.