United States clinical practice experience with eculizumab in myasthenia gravis: symptoms, function, and immunosuppressant therapy use

Background/objectives: The phase 3 REGAIN study and its open-label extension demonstrated the efficacy of the complement C5 inhibitor eculizumab in patients with treatment-refractory, acetylcholine receptor antibody-positive generalized myasthenia gravis (gMG). The aim of the ELEVATE study was to assess the effectiveness of eculizumab in clinical practice in adults with MG in the United States.

Methods: A retrospective chart review was conducted in adults with MG who initiated eculizumab treatment between October 23, 2017 and December 31, 2019. Outcomes assessed before and during eculizumab treatment using a pre- versus post-treatment study design included Myasthenia Gravis-Activities of Daily Living (MG-ADL) total scores; minimal symptom expression (MSE); physician impression of clinical change; minimal manifestation status (MMS); and concomitant medication use.

Results: In total, 119 patients were included in the study. A significant reduction was observed in mean MG-ADL total score, from 8.0 before eculizumab initiation to 5.4 at 3 months and to 4.7 at 24 months after eculizumab initiation (both p < 0.001). At 24 months after eculizumab initiation, MSE was achieved by 19% of patients. MMS or better was achieved by 30% of patients at 24 months. Additionally, 64% of patients receiving prednisone at eculizumab initiation had their prednisone dosage reduced during eculizumab treatment and 13% discontinued prednisone; 32% were able to discontinue nonsteroidal immunosuppressant therapy.

Discussion: Eculizumab treatment was associated with sustained improvements in MG-ADL total scores through 24 months in adults with MG. Prednisone dosage was reduced in approximately two-thirds of patients, suggesting a steroid-sparing effect for eculizumab.