Alexion Pharmaceuticals’ flagship drug has made a strong case it can treat yet another rare disease, and the company is now mapping out plans to file for approval in the U.S. and other regions.
The Boston company released preliminary Phase 3 data for eculizumab (Soliris) as a treatment for neuromyelitis optica spectrum disorder (NMOSD), a central nervous system disorder that has no FDA-approved treatment. The Alexion antibody drug is already approved to treat two ultra-rare blood diseases: paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemoyltic uremic syndrome (aHUS). Investors welcomed the prospect of adding another disease to a product that is already a blockbuster seller, and the stock price of Alexion (NASDAQ: ALXN) at one point rose 7 percent Monday morning to more than $130 per share.
NMOSD is a rare autoimmune disorder that causes inflammation in the optic nerve and spinal cord. It’s sometimes misdiagnosed as multiple sclerosis, but it typically involves different parts of the brain than MS, and the severity of the attacks associated with the disease can be more severe, according to the Transverse Myelitis Association. The disease also develops differently. While MS is thought to be related to the T cells of the immune system, NMOSD is related to the immune system producing auto antibodies, which are antibodies that target a patient’s own proteins. In this disease, these antibodies target AQP4, a protein that is important for the survival of nerve cells. Over the course of dealing with their disease, NMOSD patients experience unpredictable relapses that make their symptoms and disability worse.
Alexion tested its drug, an infusion given every two weeks, in a Phase 3 study enrolling 143 NMOSD patients. The study’s main goal was reducing the risk of relapse. The Alexion drug hit that goal, reducing the relapse risk by 94.2 percent compared to a placebo. After 48 weeks, Alexion says 97.9 percent of patients treated with its drug were relapse free, compared to 63.2 percent of patients given a placebo. Alexion says that the safety profile of its drug was consistent with earlier studies of the drug, and added that no cases of meningococcal infection were observed. The Centers for Disease Control and Prevention has warned that patients treated with the drug are at high risk for such infections.
Eculizumab is Alexion’s top seller by far, accounting for $3.1 billion in global sales last year. The encouraging data for eculizumab in NMOSD come at a time of transition for the company. Two years ago, Alexion faced allegations of improper sales practices associated with the drug. During an inquiry into those practices, then-CEO David Hallal and CFO Vikas Sinha resigned for “personal reasons.” A little more than a year ago, Alexion announced a corporate restructuring that would cut 20 percent of staff and relocate its headquarters from New Haven, CT, to Boston.
Alexion says it will discuss the study results with regulators in the U.S., Europe, and Japan, with the goal of filing for regulatory approval in those geographies.
The Phase 3 results signal a likely FDA approval for the drug in NMOSD, Stifel analyst Paul Matteis wrote in a research note. But he added that this market is smaller than those of the two rare blood disorders that the drug currently treats. Separately, Leerink Partners analyst Geoffrey Porges wrote that he expects regulatory filings could be completed by the end of the year, setting the stage for a potential launch in the U.S. next year. Porges estimates that approval of eculizumab for treating NMOSD could bring Alexion another $500 million to $700 million in annual revenue.