Effectiveness of Eculizumab Treatment by Time from Diagnosis in Patients with Generalized Myasthenia Gravis: A Retrospective Electronic Medical Record Analysis
Srikanth Muppidi1, Justin Lee2, Ali Habib3, James Howard4, Andrew Klink5, Adrian Kielhorn2, Guido Sabatella2, Richard Nowak6
1Stanford Neuroscience Health Center, 2Alexion, AstraZeneca Rare Disease, 3University of California, Irvine, 4The University of North Carolina at Chapel Hill School of Medicine, 5Cardinal Health, 6Yale University School of Medicine
Objective:
To assess MG-ADL total score changes from baseline to week 26 in patients initiated on eculizumab before or after 2 years of gMG diagnosis in clinical practice.
Background:
Complement component 5 inhibitors eculizumab and ravulizumab are approved treatments for acetylcholine receptor antibody positive generalized myasthenia gravis (gMG). In the pivotal CHAMPION MG trial, improvements in functioning were numerically greater in patients receiving ravulizumab ≤2 vs >2 years from diagnosis (assessed by Myasthenia Gravis Activities of Daily Living; MG-ADL).
Design/Methods:
Physician-reported electronic medical records of adults with gMG who initiated eculizumab between October 23, 2017 and December 31, 2019 in 14 US sites were included. Patients initiating eculizumab ≤2 years or >2 years after diagnosis were defined as early or late initiators, respectively. Median MG-ADL scores and percentage changes from baseline are reported due to non-normal data distribution; age at eculizumab initiation was a covariate in the mixed model repeated measure analysis.
Results:
Fourteen early and 41 late initiators were identified. Respectively, mean (standard deviation) ages at eculizumab initiation were 66.5 (9.5) and 54.4 (17.7) years, and mean baseline MG-ADL total scores were 8.64 (1.74) and 6.78 (3.84). MG-ADL scores and percentage changes for all patients improved at week 26 compared to baseline; however, improvements were significantly greater for early compared with late initiators (6.5 vs 3.0, p<0.05; 78% vs 50%, p<0.05). A sensitivity analysis using cutoff of ≤5 or >5 years after diagnosis found a confirming trend for greater symptom improvement in earlier initiators, but this did not meet statistical significance compared with late initiators (6.0 vs 2.0, p=0.07; 71% vs 50%, p=0.57).
Conclusions:
In addition to previous findings from CHAMPION MG, this retrospective data analysis from US clinical practice provides further evidence that eculizumab or ravulizumab treatment within 2 years of gMG diagnosis may offer a greater clinical benefit compared with later initiation.