Eculizumab was approved in October 2017 for AChR antibody-positive gMG in the US. Published data on real-world use and effectiveness of eculizumab are limited.

A retrospective US chart-review study was conducted. Data were abstracted by physicians from their patients’ electronic medical records. Patients with gMG aged ≥18 years who had received eculizumab for ≥6 months were included in this analysis. Patient outcomes for two consecutive 6-month periods – before and during eculizumab treatment – were analyzed. Outcomes included MG crisis, MG exacerbation, and MG-related hospitalization. Descriptive statistical analyses for each period are presented.

In 84 patients with gMG, mean (SD) age was 46.3 (19.2) years and 55% were female; 74% were white and 16% black/African American. At eculizumab initiation the median MG Activities of Daily Living score was 8. The majority of patients were clinically categorized as Myasthenia Gravis Foundation of America Class II–III (71%), 10% as Class I, and 14% as Class IV (5% unknown). MG crisis occurred in 25% of patients in the 6 months before initiating eculizumab and in 1% of patients during the following 6-month period in which they received eculizumab. MG exacerbations were experienced by 38% and 10%, respectively. The proportion of patients hospitalized due to MG crisis was 21% in the 6 months before eculizumab initiation and 1% during 6 months’ eculizumab treatment; for MG exacerbation the proportions were 14% and 4%, respectively.

Results from this pilot study suggest that real-world eculizumab treatment is associated with substantial reductions in MG crises/exacerbations and related hospitalizations in patients with gMG, consistent with outcomes of the Phase 3 REGAIN study and its open-label extension. A larger real-world study of longer duration is underway to confirm these findings.