Summary: Alexion Pharmaceuticals announced Sept. 23, 2017, that the U.S. Food and Drug Administration (FDA) has approved eculizumab (brand name Soliris) as a treatment for adult patients with generalized Myasthenia Gravis (gMG) who are anti-acetylcholine receptor antibody-positive. Soliris is the first in a new class of drugs to be approved for MG in the U.S.
Soliris is not a cure for MG, but it may lessen the symptoms experienced by people living with generalized MG. Soliris was tested in clinical trials in patients who had previously failed immunosuppressive treatment and continued to suffer from significant unresolved disease symptoms such as difficulties seeing, walking, talking, swallowing and breathing. Patients taking Soliris had improved scores on scales designed to assess quality of life and symptom burden including double vision, ptosis (drooping of the eyelids), swallowing, speech, breathing, and use of arms and legs.
Statement from MDA President and Chief Executive Officer Lynn O’Connor Vos:
“MDA celebrates the approval of Soliris to treat generalized myasthenia gravis — the first in a new class of drugs to be approved for MG in the U.S. — and we offer our deepest thanks to the dedicated researchers, and the individuals and families who participated in clinical trials to make this development possible.
“This is truly an unprecedented time, when more experimental therapies than ever before are reaching late-stage development and moving through the regulatory review process. In just the past few years, our community has seen six FDA approvals for drugs to treat neuromuscular diseases in MDA’s program — including periodic paralysis, Duchenne muscular dystrophy, ALS, spinal muscular atrophy and now myasthenia gravis. The origins of four of those six drugs can be traced directly to MDA research dollars.
“We are closing in on solutions for people living with neuromuscular diseases and will continue to fund critical scientific research, facilitate clinical trial participation, and advocate for policies that enable safe and effective therapy options to be made available as quickly as possible.”
Background: Patients with generalized MG experience muscle weakness in the head, neck, trunk, limb and respiratory muscles. An estimated 10-15 percent do not respond to treatments that are typically helpful in other MG patients.
Profound weakness throughout the body often is accompanied by slurred speech, impaired swallowing and choking, double vision, upper and lower extremity weakness, disabling fatigue, shortness of breath due to respiratory muscle weakness, and episodes of respiratory failure. Patients with generalized MG may require hospitalization, often involving intensive care unit stays.
Soliris is a terminal complement inhibitor that targets a part of the immune system called the complement system, which is responsible for helping antibodies clear damaged cells and potentially toxic microbes that could cause infections. In MG, antibodies whose job it is to target these toxic pathogens, instead inappropriately recruit the complement system and target the space across which nerve fibers transmit signals to muscle fibers, called the neuromuscular junction (NMJ). In patients with anti-acetylcholine receptor antibody-positive MG, the body’s own immune system turns on itself to produce antibodies against the acetylcholine receptor, a receptor located on muscle cells at the NMJ, activating the complement system. Soliris is thought to work in MG by inhibiting the complement pathway to prevent destruction of the neuromuscular junction.
MDA has not been directly involved in the development of Soliris for MG, but we have invested in previous research investigating complement inhibition as a therapeutic strategy for MG. In addition, MDA currently is funding research focused on developing improved complement inhibitors. (Soliris is a complement inhibitor drug.)