Eculizumab Now Approved in Japan for Children With Generalized Myasthenia Gravis

Treatment with eculizumab led to significant improvements in the Quantitative Myasthenia Gravis total score at week 26.

Eculizumab (Soliris®) has been approved in Japan for the treatment of children with generalized myasthenia gravis (gMG), according to a press release from Astra Zeneca, the developers of the treatment.

“gMG is challenging to manage in paediatric patients, as current therapies available to this population, such as immunosuppressants, may not offer adequate control as the disease progresses,” said Keiko Ishigaki, MD, PhD, from the Tokyo Women’s Medical University in Japan.

Read more about the symptoms of MG

“Today’s expanded approval of Soliris in Japan demonstrates the impact of C5 complement inhibition in treating gMG, offering paediatric patients a targeted option with the potential to preserve muscle function and reduce disease severity,” Dr. Ishigaki added.

The approval is based on results from a phase 3 clinical trial evaluating the efficacy, safety, pharmacodynamics, and pharmacokinetics, of eculizumab in children, who are 12 to 17 years of age and who have refractory gMG. The trial recruited 11 patients in the US, Japan, and The Netherlands. 

It showed that eculizumab was clinically beneficial in children with gMG who previously failed immunosuppressive treatment and continued to experience significant disease symptoms. 

Treatment with eculizumab led to significant improvements in the Quantitative Myasthenia Gravis total score at week 26, the primary endpoint of the study.

Most of the reported adverse events were considered mild or moderate with the most common adverse events being headache and nasopharyngitis.

MG is an autoimmune disease characterized by an immune attack against acetylcholine receptors in the neuromuscular junction. The disease can be localized or generalized. gMG affects the bulbar, limb, and respiratory muscles.

Eculizumab is a first-in-class C5 complement inhibitor, which blocks the action of the C5 protein in the terminal complement cascade, which is over-activated in the case of MG leading to an immune attack against healthy cells and tissues. It was first approved in Japan in 2017 for the treatment of some adult patients with gMG. It is also approved in the US for the treatment of some adults with gGM.

This article originally appeared on Rare Disease Advisor


  1. Soliris approved in Japan for paediatric patients with generalised myasthenia gravis (gMG). News release. Astra Zeneca; August 24, 2023.
  2. A phase 3 open-label study of eculizumab in pediatric participants with refractory generalized myasthenia gravis (gMG). US National Library of Medicine. Updated July 27, 2023. Accessed September 4, 2023.