Shares of argenx plunged 15.9% to $781.00 on October 8 after the company killed its late-stage trial for Sjögren's disease, erasing roughly $9 billion in market value in a single session. The failure strips away a growth avenue investors had been counting on — but the question now is whether argenx's towering commercial franchise is strong enough to absorb the hit.
The Drug Didn't Work for Sjögren's, and There's No Salvaging This Trial. Argenx discontinued the Phase 3 UNITY study of its lead antibody in Sjögren's disease after an independent monitoring committee recommended stopping for futility.
Patients were randomized to receive the drug or a placebo, with the primary endpoint measuring change in systemic disease activity at Week 48. The data simply showed the drug could not outperform a placebo — a definitive miss that leaves no room for a reread or a subgroup rescue. Sjögren's disease is a chronic autoimmune condition with no approved systemic therapies, and an estimated U.S. patient pool of roughly 500,000. Losing access to that market removes a potentially meaningful revenue layer from argenx's long-term projections.
The Core Business Is Massive — and Still Growing Fast. Argenx delivered $1.5 billion in second-quarter VYVGART product sales, up 60% year over year.
For the first half of 2026, VYVGART product net sales reached $2.8 billion, compared with $1.7 billion a year earlier.
Analysts had modeled approximately $6.5 billion in full-year VYVGART sales , driven by expanded use across multiple nerve and muscle diseases. The Sjögren's failure does not touch that franchise, which remains the stock's backbone.
A Celiac Disease Win Softens the Blow — But Only Slightly. Argenx simultaneously announced positive Phase 2 results for a first-in-class drug targeting celiac disease, meeting the study's primary endpoint (p=0.0176), with plans to advance into Phase 3.
Roughly 1% of people worldwide have celiac disease, and incidence is rising about 7.5% per year — a large, untapped market with no approved therapies. But Phase 2 success is years away from revenue, and investors clearly weighed the near-term loss more heavily.
The Pipeline Still Has Near-Term Catalysts to Watch. Argenx expects data from its registrational study of empasiprubart in multifocal motor neuropathy in the fourth quarter of 2026, with two additional late-stage readouts in 2027. These trials will test whether argenx can diversify beyond its single blockbuster. For now, the stock's $781 price tag reflects a market recalibrating around a narrower — but still formidable — growth story.