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Muscular Dystrophy Association Celebrates FDA Approval of argenx's Vyvgart Hytrulo Injection for Treatment of Generalized Myasthenia Gravis

NEW YORK, June 20, 2023 -- The Muscular Dystrophy Association (MDA) celebrates the US Food and Drug Administration (FDA) approval of subcutaneous (SC) Vyvgart Hytrulo (efgartigimod alfa and hyaluronidase-qvfc),for the treatment of generalized myasthenia gravis (gMG) in adult patients who are anti-acetylcholine receptor (AChR) antibody positive. Vyvgart Hytrulo is the first FDA-approved SC injectable for gMG and will be made available and marketed in the United States by argenx.

Vyvgart was initially approved for use in the US and Europe in 2021 as an intravenous (IV) infusion administered once weekly over a period of four weeks by a healthcare professional in an infusion center. The new SC formulation can now be administered as a single injection (1,008 mg fixed dose) at home or in a physician’s office.

Muscular Dystrophy Association celebrates FDA approval of subcutaneous Vyvgart Hytrulo for treatment of generalized myasthenia gravis.
Muscular Dystrophy Association celebrates FDA approval of subcutaneous Vyvgart Hytrulo for treatment of generalized myasthenia gravis.

MG is a rare and chronic autoimmune disease where IgG autoantibodies disrupt communication between nerves and muscles, causing debilitating and potentially life-threatening muscle weakness. Approximately 85% of people with MG progress to gMG within 24 months, where muscles throughout the body may be affected. Recommended treatments for gMG include drugs that may alleviate symptoms, such as cholinesterase inhibitors, or treatments that may alter the disease course, such as immunosuppressive drugs or surgery (thymectomy). Over the past six years, three therapies have been approved by the FDA to treat adults living with acetylcholine receptor antibody-positive (AChR ab+) gMG. These include eculizumab (Soliris), efgartigimod (Vyvgart), and ravulizumab (Ultromiris), all of which are administered by IV infusion.

Vyvgart is a human antibody fragment that binds to the neonatal Fc receptor (FcRn), resulting in the reduction of circulating immunoglobulin G (IgG) antibodies and is currently the first-and-only FDA-approved neonatal Fc receptor blocker and the first approved therapy designed to reduce IgG antibodies, an underlying driver of gMG. Although treatment with Vyvgart will not cure gMG, it could lead to functional improvements that improve the daily life of individuals with gMG.

“We are delighted to see a continued commitment to the MG community,” said Stephanie Madole, mother of two children, Elizabeth and Charlotte, who are living with gMG and relapsing polychondritis. “I have made it my passion to raise awareness for MG, advocate for other families’ care, and support innovative research. While my own daughters are currently on other medications, I feel the new formulation of Vyvgart has the potential to be more convenient, which will definitely make a difference for many families, The new formulation replaces a one-hour infusion with a shot given at home; which matters for families like ours who drive 8 hours round trip for infusions and our girls miss school and days where they’re able to spend time just being kids. Continued research and more therapeutic options are imperative, and this is an exciting step forward.”

“This is a significant and timely approval as June is Myasthenia Gravis Awareness Month,” said Sharon Hesterlee, Ph.D., Chief Research Officer, MDA. “The approval of an additional formulation of Vyvgart is another important step toward treating gMG, a disease that, up until a few years ago, had no approved therapies. Now those living with gMG will have the choice to receive a subcutaneous injection of an effective disease modifying therapeutic."

“Subcutaneous efgartigimod will be a welcome addition to the growing number of targeted therapies for myasthenia gravis, said Alexander Fay, MD, a neurologist at the University of California, San Francisco (UCSF) Hospital MDA Care Center,Giving patients the option to administer medication at home, instead of an infusion center or hospital, can reduce travel, missed work and missed school, and will hopefully improve quality of life for patients with MG.”

“New methods of administering safe and effective treatments are crucial to ensuring the gMG community can access life-improving treatments in the ways they desire,” said Paul Melmeyer, Vice President, Public Policy and Advocacy, MDA. “We applaud the approval of the subcutaneous formulation of Vyvgart which will offer people living with gMG multiple ways to receive treatment through various administrations and an individualized dosing schedule. MDA’s advocacy efforts for gMG not only include advocating for the development and subsequent approval of safe and effective treatments for gMG, but also include increasing access to the best care options for the MG community as well as breaking down societal barriers placed in front of the MG community.”

About generalized myasthenia gravis

MG is a relatively uncommon disease, with a prevalence of about 14 cases per 100,000. There are two clinical forms of MG: ocular and generalized. In ocular MG, muscle weakness often first appears in the muscles of the eyelids and other muscles that control movement of the eye (extraocular muscle). In gMG, the weakness involves the ocular muscles and a variable combination of the arm, legs, and respiratory muscles. MG can occur at any age; the data presents a peak among females in their second decade of life and older males in their sixth to eighth decades. Today, researchers are working to understand the specifics of the autoimmune problems in MG and to refine their detection and treatment. An important area of current research is understanding the physiology of the neuromuscular junction (NMJ), with the goal of improving its function despite an immune system attack. Download MDA’s Myasthenia gravis (MG) Fact Sheet.

Clinical trials support approval of SC Vyvgart

The FDA based its decision to grant approval to Vyvgart Hytrulo on the positive results of the ADAPT-SC phase 3 trial, which evaluated the relative safety, efficacy, and pharmacokinetics/pharmacodynamics of Vyvgart Hytrulo compared to IV-infused Vyvgart in 110 participants with gMG. In the ADAPT-SC study, the primary endpoint of noninferiority to IV Vyvgart was met and Vyvgart Hytrulo demonstrated reduction in anti-AChR antibody levels at day 29 after treatment comparable to the effects of IV Vyvgart in adult gMG patients. Additional key secondary endpoints were also met, demonstrating comparable efficacy to IV Vyvgart.

Vygart Hytrulo was generally well-tolerated in trial participants, with the most common adverse reactions being injection site reactions (ISRs).

Muscular Dystrophy Association’s investment in gMG research

MDA’s commitment to research on myasthenia gravis (MG) began many years ago when little was known about the cause of MG and its mortality rate was high. In the early 1970s, MDA-funded researchers helped establish the autoimmune nature of MG, demonstrating that people with the disease have a reduced number of acetylcholine (ACh) receptors and that antibodies to the receptors can induce MG in preclinical studies. These discoveries led swiftly to the lifesaving use of immunosuppressant drugs to treat the disease.

MDA-supported scientists in countries around the world are working to reveal numerous facets of MG, from identifying possible causes and triggers to understanding the disease's molecular underpinnings to developing specific treatment strategies. For more, see Research.

About Muscular Dystrophy Association

Muscular Dystrophy Association (MDA) is the #1 voluntary health organization in the United States for people living with muscular dystrophy, ALS, and related neuromuscular diseases. For over 70 years, MDA has led the way in accelerating research, advancing care, and advocating for the support of our families. MDA's mission is to empower the people we serve to live longer, more independent lives. To learn more visit mda.org and follow MDA on Instagram, Facebook, Twitter, TikTok, LinkedIn, and YouTube.