Argenx’s Vyvgart will now be available in the U.S. as a more convenient subcutaneous formulation 18 months after its first approval.
Pictured: Vyvgart Hytrulo Bottle/argenx
Amsterdam-based argenx brings another first to the market for adults with generalized myasthenia gravis, a chronic autoimmune disease. The FDA approved a subcutaneous formulation of Vyvgart on Tuesday that can be given with a shot at home.
Vyvgart (efgartigimod) was the first in a new class of medication when approved by the FDA in 2021. The original formulation was a one-hour intravenous infusion for generalized myasthenia gravis (gMG) patients positive for the anti-acetylcholine receptor (AChR) antibody.
In this chronic autoimmune disease, antibodies block and destroy the communicative receptors between nerves and muscles. The result is progressive muscle weakness in the voluntary muscles of the body, particularly those around the eyes, mouth, throat and limbs.
Vyvgart is an antibody fragment that binds to the neonatal Fc receptor to prevent recycling of immunoglobulin G (IgG) back into the blood. Reduced overall levels of IgG includes a reduction in the abnormal AChR antibodies, which are present in approximately 85% of the gMG patient population. The AChR antibodies are what block the acetylcholine receptors from being able to receive signals from the nerve to stimulate a muscular response.
The new subcutaneous formulation—a single injection for four weeks—is a major win for the gMG community.
“The new formulation replaces a one-hour infusion with a shot given at home; which matters for families like ours who drive eight hours round trip for infusions and our girls miss school and days where they’re able to spend time just being kids,” Stephanie Madole, an advocate and mother of two children with gMG, said in a Muscular Dystrophy Association press release.
Marketed as Vyvgart Hytrulo, the under-the-skin injection will be available for patients in the U.S. by July. Marketing applications for approval in Europe and Japan are still underway, expected by the end of 2023 and the first quarter of 2024, respectively.
Vyvgart is argenx’s first approved product and is on track to becoming a blockbuster for the biopharma, argenx CEO Tim Van Hauwermeiren told Endpoints News. After hitting the market last year, the IV formulation racked up just over $400 million in sales in 2022. First quarter sales this year were $218 million.
The cost for both formulations is roughly the same, according to Endpoints—around $225,000 annually for each patient, depending on how frequently the drug is needed. Initial administration is a four-week cycle, then new cycles are started per patient’s needs.
Trial data showed the new formulation to be similarly effective to the intravenous version. Previous data showed 68% of gMG patients on Vyvgart infusions had significant improvement to their daily function compared to 30% on placebo. Patients on argenx’s drug also had a superior response on a measure of muscle weakness compared to placebo.
Efgartigimod is being tested by argenx in multiple autoimmune indications. The company anticipates submitting for approval in primary immune thrombocytopenia in Japan this year.
Kate Goodwin is a freelance life science writer based in Des Moines, Iowa. She can be reached at kate.goodwin@biospace.com and on LinkedIn.
