A randomized, double‐blind, placebo‐controlled phase II study of eculizumab in patients with refractory generalized myasthenia gravis

ABSTRACT 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. Muscle Nerve, 2013