Eculizumab was well tolerated and effective in a wide spectrum of Japanese patients with generalized myasthenia gravis (MG) who were anti-acetylcholine receptor antibody-positive (AChR Ab+) and had a disease that was difficult to control, according to a new study published in Clinical and Experimental Neuroimmunology

Eculizumab is an inhibitor of the complement protein C5 that is approved in Japan. Here, researchers led by Kimiaki Utsugisawa, MD, from the Department of Neurology at Hanamaki General Hospital in Japan assessed the safety and effectiveness of eculizumab as part of mandatory postmarketing surveillance.

The researchers analyzed 134 patients who completed case-report forms 26 weeks after the start of eculizumab treatment. 

Read more about the etiology of MG

The results showed that the majority of patients (78%) were continuing treatment with eculizumab after 26 weeks. Forty-nine patients (37%) reported adverse drug reactions, of which headaches were the most frequent, reported by 10 patients.

Patients had improvements in their Myasthenia Gravis-Activities of Daily Living (MG-ADL) scores regardless of sex, age at diagnosis, age at the start of treatment, disease severity, or MG-ADL score at the start of treatment.

For patients who were treated with corticosteroids, the proportion receiving low-dose treatment increased from 7% to 26.4% after the initiation of eculizumab.

The authors concluded that these findings “support the safety and effectiveness of eculizumab in clinical practice” in a broad spectrum of adult patients in Japan with generalized MG who were AChR Ab+.

MG is the most common condition affecting the neuromuscular junction. It is caused by an antibody-mediated autoimmune response damaging muscle receptors that receive nerve impulses. The majority of patients have antibodies against acetylcholine receptors, but some patients may have antibodies against muscle-specific receptor tyrosine kinase or lipoprotein-related protein 4. There are also some patients who are seronegative or have no detectable antibodies in the blood.


Murai H, Suzuki S, Fukamizu Y, Osawa T, Kikui H, Utsugisawa K. Safety and effectiveness of eculizumab in Japanese patients with generalized myasthenia gravis: analysis of 1-year post-marketing surveillance. Clin Exp Neuroimmunol. Published online June 2, 2022. doi:10.1111/cen3.12716.