The FDA has approved Rystiggo, a developed by UCB in Brussels, to treat two types of myasthenia gravis. The approval was based on the results of the Phase III MycarinG trial recently published in Lancet Neurology. Significant improvements were reported in such areas as breathing, swallowing, rising from a sitting position, and speech.
According to the National Institute of Health, myasthenia gravis is an autoimmune disease that can involve respiratory muscles and also generalized muscle weakness.
Rystiggo is injected under the skin (subcutaneous) and may be used against muscle weakness in cases of IgG. The drug blocks a protein called the neonatal Fc receptor that regulates various levels of autoantibodies resulting in fewer circulating IgG autoantibodies.
Rystiggo is the only drug approved by the FDA to treat adult patients who are anti-muscle-specific tyrosine kinase antibody positive as well as anti-acetylcholine receptor positive.
IgG autoantibodies disturb synaptic transmission by targeting certain proteins that bind to the post-synaptic membrane preventing the nerves from stimulating muscles.
Such muscular weakness causes a potentially fatal disturbance to respiration. It can also cause problems with swallowing, speech, or double vision.
The executive director of UCB issued a statement explaining that generalized myasthenia gravis (gMG) patients exhibit varying symptoms. Many patients have received steroids, immunosuppressant drugs, or acetylcholinesterase inhibitors, yet the disease can still resist treatment.
Earlier this year UCB announced the FDA’s acceptance of its filing and that UCB had been granted Priority Review.
Just last month results of the MycarinG trial’s Phase III were published showing that Rystiggo had a 3.4 change from baseline while the placebo group reported an 0.8 point change.
10% of patients who were treated with Rystiggo reported infections, hypersensitivity, headache, diarrhea, high fever (pyrexia), and nausea.
The newly approved drug will be available commercially in the United States at the end of this year. The disorder, gMG, affects between 100 to 350 per million adult patients.