The FDA has approved a new INFUSED biologic, Vyvgart (efgartigimod alfa-fcab, Argenx), for treatment of generalized Myasthenia Gravis (gMG) in adults who are acetylcholine receptor antibody positive. gMG is a rare, chronic autoimmune, neuromuscular disease.
Myasthenia gravis is characterized by debilitating and potentially life-threatening muscle weakness and rapid fatigue of any of the muscles under voluntary control. The disease can affect people of any age and is more common in women younger than 40 and in men older than 60. Roughly 3 percent of people who develop gMG will die from it.
There is no cure for myasthenia gravis, but treatment can help relieve other signs and symptoms, such as double vision, drooping eyelids, and difficulties with speech, chewing, swallowing and breathing.
Prior to the approval of Vyvgart, therapies to control gMG include corticosteroids such as prednisone (Rayos), immunosuppressants (e.g., Azasan, Imuran), mycophenolate mofetil (Cellcept), cyclosporine (Sandimmune, Gengraf, others), methotrexate (Trexall) or tacrolimus (Astrograf XL, Prograf, others). Intravenous therapies incude plasmapheresis, intravenous immunoglobulin (IVIg), and monoclonal antibodies such as Rituximab (Rituxan) and eculizumab (Soliris).
The prevalence of gMG in the United States is estimated at 14 to 20 per 100,000 population, which translates into 36,000 to 60,000 cases in the United States. gMG has a low incidence rate of 2.1 to 5.0 per million people per year in the US.
Pricing for Vyvgart was not released upon approval. By reference, Soliris is currently priced at $675,000 per year. Distribution details were not released; however, it is presumed that Vyvgart will launch into limited distribution similar to Soliris.
FDA approves Vyvgart for treatment of myasthenia gravis
The FDA announced the approval of Vygart for treatment of the chronic autoimmune, neuromusucal disease myasthenia gravis in adults who are positive for acetylcholine receptor antibody positive adults.
The approval of the investigational antibody fragment designed to target the neonatal Fc receptor is the first for the new drug class, according to a press release.
“There are significant unmet medical needs for people living with myasthenia gravis, as with many other rare diseases,” Billy Dunn, MD, director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research, said in the press release. “Today’s approval is an important step in providing a novel therapy option for patients and underscores the agency’s commitment to help make new treatment options available for people living with rare diseases.”
In a randomized, double-blind, placebo controlled, multicenter Phase 3 trial completed in 2020, patients with myasthenia gravis with acetylcholine receptor antibodies who received Vyvgart (efgartigimod, Argenx) responded to treatment at a higher rate as compared with placebo.
Since the therapy reportedly decreases levels of immunoglobulin, experts warn of an increased risk of infection. Hypersensitivity reactions are also possible, including eyelid swelling, shortness of breath, and rash. In the cases of hypersensitivity or existing infection, treatment should be either discontinued or delayed, according to the press release.