Vyvgart, an FcRn inhibitor already approved for generalized myasthenia gravis, is also being tested in myositis, Sjögren’s disease and the “clinically related” Graves disease.
Argenyx’s Vyvgart has unexpectedly failed in a Phase III trial for thyroid eye disease—a potential $550 million market opportunity. But no matter, as analysts see plenty of upside for the drug in a handful of other indications.
The late-stage UplighTED studies have been halted after a pre-planned interim analysis showed the studies were unlikely to be successful, Argenyx said in a Monday release. An independent data monitoring committee recommended the trials be stopped.
The company will conduct a more comprehensive analysis of the data to inform future research in thyroid eye disease (TED) and release more data at future medical meetings.
William Blair called the failure a surprise in a Monday morning note to clients. Vyvgart, which belongs to the FcRn inhibitor class of drugs, had previously succeeded in the “clinically related” Graves disease. The news raises questions about the biological differences between the two diseases, the analysts said. The TED indication could have added about $550 million in sales for Vyvgart, which is already approved for generalized myasthenia gravis.
But Argenyx is undergoing a full-court press to expand the therapy into new indications. Besides TED, the company is testing it in myositis and Sjögren’s disease. William Blair is “particularly confident” in these two indications, as both have had positive Phase II trials already.
Argenyx will also continue on with a Phase III test in Graves, but William Blair noted that today’s news makes that trial a riskier bet.
Meanwhile, Argenyx’s setback is Amgen’s gain. The latter company has Tepezza approved for TED, with $1.45 billion in sales already recorded for the first nine months of 2025. Virdian is also awaiting an FDA nod for veligrotug, an IGF-1R antagonist, in TED in 2026.
“For Viridian, we think the removal of another potential competitor is obviously a positive, and this would seem to raise questions about the potential for the FcRn class in this indication,” William Blair wrote.
Immunovant is further behind in the clinic with the anti-FcRn agent batoclimab, with a readout expected in the first half of next year.
Editor’s Note (Dec. 15): An earlier edition of this story said that veligrotug is an FcRb inhibitor. It is an IGF-1R antagonist. BioSpace regrets the error.
