Dive Brief:
- Argenx shares fell 15% Thursday after the Dutch biotech said its blockbuster Vyvgart medicine failed to help patients with a tough-to-treat autoimmune disease.
- An independent monitoring board recommended ending a Phase 3 study in Sjögren’s disease “for futility” following an interim analysis, Argenx said. The timing surprised analysts, who weren’t expecting results from the trial until the second half of 2027. A separate announcement of successful Phase 2 research into a new drug for celiac disease failed to mollify investors.
- Several analysts said they had not included sales for a Sjögren’s indication in their models because it was a high-risk proposition. But success would have brought big upside, with as much as $1.4 billion in peak sales for that use alone. The failure removes another “blockbuster expansion opportunity” for the Vyvgart franchise, William Blair analyst Matt Phipps wrote in a note to clients.
Dive Insight:
The success of Vyvgart has propelled Argenx into the ranks of the world’s most valuable biotechnology companies. Argenx boasts a market cap of around $50 billion even after Thursday’s slide, well above Biogen, a biotech founded in 1978 with a dozen approved products.
Argenx took the more unusual route of holding onto its first successful medicine, rather than selling itself, and has reaped the rewards. Sales of Vyvgart and a subcutaneous version called Vyvgart Hytrulo brought in $1.5 billion for the company just in the second quarter. Analyst estimates for overall annual peak sales for the drug — even without Sjögren’s — range from $11 billion to $17 billion.
“Given Argenx’s premium valuation, Phase 3 setbacks have historically resulted in sharp pullbacks that ultimately present buying opportunities,” Phipps wrote. He said he’s still optimistic about the chances to expand the use of Vyvgart as well as other products in Argenx’s pipeline.
There are no treatments approved to alter the course of Sjögren’s, which causes the immune system to attack moisture-producing glands and often leaves patients with fatigue, dry eyes and pain in the mouth and joints. But both Novartis and Amgen have reported successful Phase 3 trials of experimental drugs for the condition.
Argenx had been optimistic it would succeed in developing a treatment based on Phase 2 results released last year and early success for a similar experimental drug from Johnson & Johnson. Immunovant is also developing a medicine in the class, known as FcRn inhibitors.
This is not the first setback for Argenx as it works to expand use of the Vyvgart franchise. The company announced study failures in primary immune thrombocytopenia and a skin condition called pemphigus in 2023. Then in 2025, Argenx discontinued development of Vyvgart for thyroid eye disease.
Both Vyvgart and Vyvgart Hytrulo are currently approved to treat generalized myasthenia gravis, a muscle weakening disease. Vyvgart Hytrulo is also approved to treat chronic inflammatory demyelinating polyneuropathy.
Investors are focusing less on the other drug Argenx highlighted on Thursday, though it could still become a blockbuster. The company acquired the medicine, known as FB102, as part of a $2.2 billion takeover of Forte Biosciences this year. The new Phase 2 study showed it can prevent gluten-induced intestinal damage in patients with celiac disease, Argenx said.
The market has a large unmet need, TD Securities analyst Yaron Werber wrote in a note to clients. “We view today’s result as derisking a second franchise rather than merely adding another Vyvgart indication,” offering more diversity to the pipeline, he said. He models $988 million in peak sales for the drug in celiac disease.
