- A late-stage trial concluded Alexion's Soliris (eculizumab) did not show a statistically significant benefit in patients with refractory generalized myasthenia gravis (gMG). The primary end-point in the randomized, double-blind, placebo-controlled trial was MG-ADL---an index of activities of daily living for patients wtih MG.
- Myasthenia gravis is a rare disease, affecting roughly 20 out of every 100,000 people. Roughly 10% to 15% of patients with MG have gMG.
- Soliris (eculizumab) generated $2.59 billion in sales last year. It is approved for two indications--paroxysmal nocturnal hemoglobinuria (PNH) to reduce hemolysis and atypical hemolytic uremic syndrome (aHUS) to inhibit complement-mediated thrombotic microangiopathy, or TMA (blood clots in small vessels). These are both very rare diseases.
Although patients with gMG treated with Soliris did not achieve the primary endpoint in the study at the 26-week mark, they did show some improvement in the secondary endpoint---the Quantitative Myasthenia Gravis (QMG) Test, a physician-administered test in which the physician assesses changes in a patient's status.
Generally, patients with MG are treated with immunosuppressive agents, which help address the myriad symptoms related to muscle weakness, including ocular weakness, problems speaking. extreme fatigue and sometimes respiratory failure, as labored breathing is part of the overall set of symptoms. When these therapies fail, patients are said to have gMG.
Alexion maintains that the unmet medical need is such that the improvements shown in the primary endpoint--though not statistically significant--along with the QMG improvements could help support their application for gMG.
Alexion shares fell more than 9% Monday after it made the announcement about the trial.