The biologic has the potential to deliver effective treatment for adult patients with generalized myasthenia gravis, but it comes at a high cost.
This week, drug maker Alexion announced that the FDA has approved its eculizumab (Soliris) for the treatment of adult patients with generalized myasthenia gravis (gMG), a progressive autoimmune neuromuscular disease, who are anti—acetylcholine receptor (AchR) antibody-positive.
The monoclonal antibody, which also gained approval to treat gMG from the European Medicines Agency in August 2017, is a complement inhibitor. Activation of the complement system plays a major role in the symptoms and potentially life-threatening complications of gMG. Eculizumab selectively inhibits the terminal complement cascade, targeting the cause of the disease.
“Today’s approval is a significant milestone for Alexion and, more importantly, for the subset of patients with anti-AchR antibody-positive gMG who continue to suffer from significant unresolved disease symptoms despite existing treatment options,” said John Orloff, MD, executive vice president and head of research and development at Alexion. “We are proud that we could apply our deep understanding of complement biology to develop Soliris for the treatment of patients with this debilitating neuromuscular disorder.”
Eculizumab is also approved by the FDA to treat paroxysmal nocturnal and atypical hemolytic uremic syndrome, and is the first newly approved drug to treat gMG in more than 60 years. The biologic has the potential to deliver effective treatment for this underserved patient population, but it comes at a high cost; Fierce Pharma has estimated the annual cost of the drug per US patient at $536,629, making the drug among the most expensive therapies in the world (by comparison, Novartis’ newly approved CAR T-cell therapy, tisagenlecleucel, is listed at a price of $475,000).
Seeking to protect its sales of the expensive innovator biologic, Alexion also sought, and obtained, 3 new US patents covering eculizumab. The patents are directed to composition of matter, pharmaceutical formulations, and methods of treatment, and will protect the drug from biosimilar competitors, such as Amgen’s proposed ABP 959, until 2027.
Notably, other biologics—which have cheaper biosimilar competition on the horizon—have the potential to serve as highly effective therapies for gMG. Rituximab has been demonstrated to have long-lasting clinical benefits in patients with drug-resistant gMG. However, rituximab’s developer, Roche, has not sought a gMG indication for the drug.