Real-world experience of eculizumab treatment for generalized myasthenia gravis: initial data from a registry of patients with generalized myasthenia gravis in the USA

ABSTRACT

Objective: To describe the baseline characteristics and interim treatment outcomes of registry participants with generalized myasthenia gravis (gMG) treated with eculizumab in real-world clinical practice in the USA. Background: Clinical trials have shown that eculizumab improves clinical outcomes in individuals with refractory gMG. The Alexion-sponsored gMG Registry collects real-world data on treatment patterns and effectiveness of eculizumab in gMG. Design/Methods: Adults with gMG who had ever received eculizumab enrolled in the Alexion-sponsored gMG Registry (NCT04202341) from December 2019. After consent, demographic data, Myasthenia Gravis (MG) activities of daily living (ADL) total scores, MG Foundation of America (MGFA) classification and serious adverse events (SAEs) were collected from medical records at two time points before eculizumab initiation (within prior 6 months) and at Registry enrollment (first Registry assessment during eculizumab treatment). Results: As of February 28, 2021, 59 adults with gMG had enrolled in the Registry (male, 54.2%;mean [range] age at MG diagnosis, 58.3 [16.0-84.0] years). Mean (range) time from eculizumab initiation to Registry enrollment was 697.1 (7.0-2435.0) days. Mean (standard deviation) MG-ADL total score decreased with eculizumab, from 8.3 (3.71) before eculizumab to 3.1 (3.43) at first Registry assessment during treatment (n=38). MGFA classification improved with eculizumab (n=32) before eculizumab, MG was class I (0.0% of patients), II (40.6%), III (53.1%) or IV (6.3%);at first Registry assessment during treatment, MG was class I (25.0%), II (62.5%), III (12.5%) or IV (0.0%). SAEs (lung adenocarcinoma, respiratory failure, atrial fibrillation, heart failure, colostomy closure, COVID-19, death) were reported in six patients. There were two deaths (unrelated to eculizumab). No meningococcal infections were reported. Conclusions: Initial analyses of Registry data showed that MG-ADL total score and MGFA classification improved with eculizumab, and that eculizumab was generally well tolerated. These findings provide additional evidence of the effectiveness of eculizumab for treating gMG in real-world clinical practice.