INTRODUCTION: Complement activation at the neuromuscular junction is a primary 
cause of acetylcholine receptor loss and failure of neuromuscular transmission 
in myasthenia gravis (MG). Eculizumab, a humanized monoclonal antibody, blocks 
the formation of terminal complement complex by specifically preventing the 
enzymatic cleavage of complement 5 (C5).
METHODS: This study was a randomized, double-blind, placebo-controlled, 
crossover trial involving 14 patients with severe, refractory generalized MG 
(gMG).
RESULTS: Six of 7 patients treated with eculizumab for 16 weeks (86%) achieved 
the primary endpoint of a 3-point reduction in the quantitative myasthenia 
gravis (QMG) score. Examining both treatment periods, the overall change in mean 
QMG total score was significantly different between eculizumab and placebo (P = 
0.0144). After assessing data obtained from all visits, the overall change in 
mean QMG total score from baseline was found to be significantly different 
between eculizumab and placebo (P < 0.0001). Eculizumab was well tolerated.
CONCLUSION: The data suggest that eculizumab may have a role in treating severe, 
refractory MG.