Encouraging results from Alexion's eculizumab Phase 2 study on generalized myasthenia gravis

Alexion Pharmaceuticals, Inc. (Nasdaq: ALXN) today announced that the Company's study of eculizumab (Soliris^®) in a small group of 14 patients with severe and refractory generalized myasthenia gravis, an ultra-rare and debilitating form of generalized myasthenia gravis (gMG), showed a strong disease improvement signal. The exploratory 14-patient study aimed to identify a clinically meaningful benefit of eculizumab in improving Quantitative Myasthenia Gravis disease severity score (QMG score) relative to placebo. The primary endpoint showed a clinically meaningful trend, and important secondary endpoints were achieved with statistical significance. Data from the Phase 2 study were presented today at the annual Scientific Session of the Myasthenia Gravis Foundation of America, Inc. (MGFA) in San Francisco. Alexion is now planning further investigation of eculizumab as a treatment for patients with severe and refractory gMG.

“We are encouraged by the results of this Phase 2 study and will evaluate the next steps in pursuing further investigation of eculizumab for patients with this severe ultra-rare disorder.”

The Phase 2 eculizumab study was a randomized, double-blind, placebo-controlled, cross-over study in 14 patients who had moderate to severe muscle weakness despite treatment with immunosuppressants. In the first treatment period of this cross-over study, which enrolled only 14 patients with severe and refractory gMG, 86% (6/7) of eculizumab-treated patients compared to 57% (4/7) of placebo-treated patients achieved a three-point reduction in their QMG score after 16 weeks of treatment, the primary endpoint of the study. This improvement was achieved more rapidly for eculizumab compared to placebo.

"These data highlight the central role of uncontrolled complement activation in severe, refractory generalized myasthenia gravis," said James F. Howard, Jr., M.D., study investigator, Distinguished Professor of Neuromuscular Disease and Chief of Neuromuscular Disorders Section, Department of Neurology, University of North Carolina at Chapel Hill. "By blocking terminal complement, eculizumab represents a potential new treatment approach for patients with severe and refractory gMG who have failed prior therapies."