New York, May 20, 2026, 16:03 (EDT)
argenx SE’s U.S.-listed shares edged higher on Wednesday but lagged a broad biotech rally after rival Immunovant reported rheumatoid-arthritis data that put fresh attention on the drug class behind argenx’s VYVGART franchise.
ARGX last traded at $803.67 late in the regular session, up about 0.7%. The iShares Nasdaq Biotechnology ETF rose 2.1% and the SPDR S&P Biotech ETF gained 3.8%, while Immunovant jumped 35.1% and its parent Roivant Sciences advanced 14.6%, market data showed.
The split matters because argenx is priced around VYVGART, an FcRn blocker. FcRn, short for neonatal Fc receptor, is a protein target used to lower circulating IgG autoantibodies, a class of antibodies that can drive autoimmune disease. VYVGART product net sales were $1.3 billion in the first quarter, up 63% from a year earlier, and Chief Executive Karen Massey called it the company’s “17th consecutive quarter of VYVGART growth.” argenx
Immunovant gave investors a new data point in the same broad antibody-lowering field. The company said IMVT-1402 showed ACR20, ACR50 and ACR70 response rates of 72.7%, 54.5% and 35.8% at week 16 in the open-label stage of a difficult-to-treat rheumatoid arthritis trial. ACR20 means at least 20% improvement in tender and swollen joint counts and other clinical measures.
Leerink Partners analyst David Risinger called the results “highly compelling,” Investor’s Business Daily reported, and said IMVT-1402 could have blockbuster potential in patients who have already failed several therapies. Investors
argenx still has the commercial head start. Earlier this month the U.S. Food and Drug Administration expanded VYVGART and VYVGART Hytrulo for all adult patients with generalized myasthenia gravis, or gMG, a rare autoimmune disease that can cause muscle weakness and fatigue; Chief Medical Officer Luc Truyen said the approval “simplifies treatment decisions” for clinicians. Argenx
In Brussels, argenx closed 0.8% higher at 690.40 euros. MarketScreener data showed a Buy consensus among 14 analysts, with an average target price of 845.01 euros.
The stock’s muted move also reflects timing. argenx’s next company-set milestones are not today’s news flow but later readouts, including myositis data expected in the third quarter and an empasiprubart study in multifocal motor neuropathy expected in the fourth quarter.
But the risk case cut both ways. Roivant’s investor deck labeled the IMVT-1402 rheumatoid-arthritis data preliminary and said the next major update is due in the second half after further analysis and FDA interactions; stronger rival data could pressure argenx’s valuation premium, while weaker follow-up would make Wednesday’s peer rally look stretched.
For now, ARGX traded less like a stock under direct attack and more like a large biotech being re-rated against a busier field. VYVGART remains the anchor. The market’s question is whether that anchor still gives argenx enough room as competitors push deeper into FcRn.
