Myasthenia gravis is caused by antibodies directed against the neuromuscular junction. Approximately 10% of patients present a generalised form, resistant to normal treatments. In this situation, different therapeutic approaches can be considered, in particular complement component 5 inhibition (C5 inhibitor) with, for example zilucoplan, ravulizumab or eculizumab. The latter obtained European marketing authorisation in 2017 in refractory generalised myasthenia gravis with acetylcholine receptor antibodies (AChR antibodies), an indication that was used in a recent update to international good practices recommendations.
Reduced symptoms, reduced concomitant treatments
Several publications that appeared at the end of 2020 reported new positive results for eculizumab in this same indication:
- during the REGAIN trial, participants treated with eculizumab over a six-month period achieved the status of “improved” and “minimal impairment” in greater numbers than those treated with the placebo (60.7% versus 41.7% and 25% versus 13.3%, respectively);
- at the end of the open-label, two-and-a-half-year extension of the REGAIN trial, in which all the participants received eculizumab, 87.1% of them achieved the status of “improved” and 57.1% of them the status of “minimal impairment”;
- due to an improvement in myasthenia symptoms, 48.7% of participants in this same extension phase of the study were able to stop or reduce the dosage of at least one concomitant immunosuppressant treatment: mycophenolate mofetil (-56% of mean dose), corticosteroids (-60.8%) and/or azathioprine (-89.1%);
- the results of a real-world study conducted in the United States show, after one year of taking eculizumab, a rapid, long lasting and significant clinical improvement in the MG-ADL score in 15 participants, a significant decrease in the number of myasthenic crises, a decrease in daily prednisone dosage in 100% of cases and discontinuation of IV immunoglobulin in the 6 patients who were receiving it before the start of C5 inhibitor treatment.
Post-intervention status in patients with refractory myasthenia gravis treated with eculizumab during REGAIN and its open-label extension. Mantegazza R, Wolfe GI, Muppidi S et al. Neurology. 2020 Nov 23:10.1212/WNL.0000000000011207.
Concomitant Immunosuppressive Therapy Use in Eculizumab-Treated Adults With Generalized Myasthenia Gravis During the REGAIN Open-Label Extension Study. Nowak RJ, Muppidi S, Beydoun SR et al. . Front Neurol. 2020 Nov 24;11:556104.