Alexion Pharmaceuticals, Inc. (NASDAQ: ALXN) today announced that Soliris® (eculizumab) has been granted orphan drug designation (ODD) by Japan's Ministry of Health, Labour and Welfare (MHLW) for the treatment of patients with myasthenia gravis (MG), a rare, debilitating neurologic disorder. In patients with MG, uncontrolled complement activation due to antibodies directed at the neuromuscular junction can ultimately lead to profound and debilitating weakness of various muscle groups throughout the body.1,2 This significant muscle weakness can impair patients' ability to walk, speak clearly, swallow and, in some cases, to breathe. "The orphan drug designation for eculizumab for MG highlights the significant need for an effective treatment option for patients in Japan who continue to suffer from the severe and debilitating symptoms of MG despite currently available therapies," said Martin Mackay, Ph.D., executive vice president and global head of R&D at Alexion. "By specifically inhibiting the terminal complement pathway, eculizumab has the potential to provide better treatment outcomes for patients with refractory generalized MG. We look forward to evaluating the clinical benefits of eculizumab in MG in our registration study, known as REGAIN, which is currently enrolling patients." The MHLW, based on the opinion of the Pharmaceutical Affairs and Food Sanitation Council, grants orphan status to drugs and medical devices that treat serious diseases of high unmet medical need that affect fewer than 50,000 patients in Japan. ODD provides drug developers with certain benefits and incentives, including priority review for marketing authorization and a period of 10 years of market exclusivity if regulatory approval is received for the designated indication. Alexion is enrolling patients in a multinational, placebo-controlled registration trial of eculizumab in patients with refractory generalized MG, known as the REGAIN (Eculizumab for REfractoryGenerAlIzed MyastheNia Gravis) study. More information on this trial is available at www.clinicaltrials.gov under the identifier NCT01997229. Soliris is a first-in-class terminal complement inhibitor and is currently approved in the United States, European Union, Japan and other countries for the treatment of patients with paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS), two debilitating, ultra-rare and life-threatening disorders caused by chronic uncontrolled complement activation. Soliris is not approved in any country for the treatment of MG. In 2014, Soliris was granted ODD in both the U.S. and EU for the treatment of MG.