Therapeutic Responses to Efgartigimod for Generalized Myasthenia Gravis in Japan

Abstract

Background and Objectives

Efgartigimod, which has been well tolerated and efficacious in individuals with generalized myasthenia gravis (MG), is available in Japan not only for the treatment of anti–acetylcholine receptor–positive (AChR+) but also anti–muscle-specific receptor tyrosine kinase (MuSK+) and seronegative generalized MG. We report details of the use of efgartigimod for generalized MG in clinical practice in Japan.

Methods

We included patients with generalized MG in the 2021 survey of Japan Myasthenia Gravis Registry (JAMG-R) study group who received an initial cycle of efgartigimod between May and September 2022. We defined “responders” as patients who achieved a score ≥2 points forMGactivities of daily living (MGADL) in the first treatment cycle. The MG composite and the Revised scale of the 15-item Myasthenia Gravis–Quality of Life scale (MG-QOL15-r) were also evaluated.