Efgartigimod for generalized myasthenia gravis with or without anti-acetylcholine receptor antibodies: a worldwide and Japanese perspective

ABSTRACT

Introduction

The management of myasthenia gravis (MG) has been improved due to immunotherapy advances, but 20% of individuals with MG are refractory to the conventional therapy, and the need for novel biological drugs remains.

Area covered

The Japanese clinical guidelines for MG published in May 2022 include the concept that treatment is often lifelong and should aim to maintain a sufficient quality of life and mental health. We provide an overview of the therapeutic strategy for generalized MG in Japan, in comparison with the international consensus. We summarize the clinical efficacy, safety, and tolerability of efgartigimod, the first approved anti-neonatal Fc receptor inhibitor for MG. A phase III study showed that efgartigimod was well-tolerated and efficacious in patients with generalized MG.

Expert Opinion

Efgartigimod is a promising biological drug for patients with moderate to severe generalized MG with or without anti-acetylcholine receptor antibodies in Japan.

KEYWORDS:

• Biological drugs
• efgartigimod
• guidelines
• myasthenia gravis
• neonatal Fc receptor
• refractory

Article highlights

• Due to advances in immunotherapy for MG, the postinterventional status is generally improved, but 20% of all patients have refractory MG, requiring a novel and effective therapy.

• The randomized, double-blind, placebo-controlled, phase III ADAPT trial showed that efgartigimod was well tolerated and efficacious in patients with generalized MG.

• Efgartigimod is expected to have benefits in not only AChR+ but also MuSK+ and seronegative refractory MG patients in Japan.

Declaration of interest

S. Suzuki received personal fees from Alexion, AstraZeneca Rare Disease, argenx, UCB, the Japan Blood Products Organization, and Asahi Kasei Medical. A. Uzawa has received honoraria from Alexion, AstraZeneca Rare Disease and argenx. H. Murai has served as a paid consultant for Alexion, AstraZeneca Rare Disease, argenx, and UCB, and has received speaker honoraria from the Japan Blood Products Organization and Chugai Pharmaceutical, and research support from the Ministry of Health, Labour and Welfare, Japan. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose. argenx provided a scientific accuracy review at the request of the journal editor.

Author contributions

S. Suzuki had full access to all the data in the study and takes responsibility for the integrity of the data and drafting of the manuscript. A. Uzawa and H. Murai were involved in drafting the article or critically revising its important intellectual content. All authors have read and approved the final version of the manuscript.

Information resources

• Howard JF, Jr., Bril V, Vu T Safety, efficacy, and tolerability of efgartigimod in patients with generalised myasthenia gravis (ADAPT): a multicentre, randomised, placebo-controlled, phase 3 trial. Lancet Neurol. 2021;20(7):526-36.

• https://www.argenx.com/news/all

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number JP20H03592.