US FDA approves Argenx's drug for muscle-weakening disease

[June 21, 2023]  By Aditya Samal and Leroy Leo

(Reuters) - The U.S. Food and Drug Administration has approved Argenx SE's under-the-skin injection for the treatment of a muscle-weakening genetic disease called generalized myasthenia gravis, the company said on Tuesday.

The drug, branded as Vyvgart Hytrulo, is expected to be available in the U.S. next month and will come at a list price of $15,773, the company told Reuters.

The FDA had approved an intravenous version of the drug in 2021 under the brand name Vyvgart, but the company expects an under-the-skin version to offer more convenient dosing than infusion into the veins. Vyvgart generated more than $400 million in global sales last year.

Vyvgart Hytrulo uses the active ingredient efgartigimod and Halozyme Therapeutics Inc's drug delivery system.

Generalized myasthenia gravis (gMG) is a chronic neuromuscular disease caused by an abnormal immune reaction that weakens the muscles in different parts of the body.

Vyvgart Hytrulo's approval was based on a late-stage study that showed it was non-inferior to Vyvgart in reducing the levels of a certain type of antibody while treating the autoimmune disease.

Argenx's new drug will compete with AstraZeneca's Soliris, an intravenous treatment.

Signage is seen outside of the Food and Drug Administration (FDA) headquarters in White Oak, Maryland, U.S., August 29, 2020. REUTERS/Andrew Kelly/File Photo

The approval could boost demand for the drug as patients switch to the subcutaneous product from the intravenous version due to ease of use, William Blair analyst Myles Minter had said ahead of the decision.

Minter expected Vyvgart Hytrulo to generate $2.5 billion in revenue for the treatment of gMG alone.

By 2025, Argenx plans to target 15 autoimmune illnesses that would be treated with efgartigimod.

Around 60,000 people in the United States have myasthenia gravis, an earlier form of gMG, according to a study published in the Journal of Medicine and Life in 2021. Argenx expects the target population for the drug to be around 17,000 patients.

(Reporting by Aditya Samal, Leroy Leo and Raghav Mahobe in Bengaluru; Editing by Shilpi Majumdar and Devika Syamnath)

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