Just shy of two months after teeing up its FcRn blocker Vyvgart Hytrulo for entry into another potential immunology niche, argenx has stumbled in a late-stage trial testing the drug against a separate target.
Following word from an independent data monitoring committee, argenx is shutting down its phase 3 unity study of subcutaneous efgartigimod—marketed as Vyvgart Hytrulo—in adults with moderate-to-severe Sjögren's disease, a chronic autoimmune condition in which the body mistakenly attacks moisture-producing glands in the eyes and mouth.
The data monitoring committee recommended ending the study for futility after getting a look at an interim analysis, argenx said in an Oct. 8 release, with the committee concluding the study’s primary endpoint would not be met.
In a bright spot for argenx and its flagship drug, Vyvgart Hytrulo’s safety scorecard was on par with its known profile, and no new concerns emerged during the trial.
Argenx is naturally “disappointed by this outcome,” said chief medical officer Luc Truyen, M.D., Ph.D., in a statement, adding that Sjögren's is “one of the most heterogeneous and complicated diseases in immunology.”
That complexity was not lost on analysts at William Blair, who remarked in a Thursday note to clients that the futility news nevertheless “comes as a surprise,” especially considering that results were not expected until well out in the second half of 2027.
The futility analysis relied on more than 500 patients, compared to 630 enrolled in the trial, which the analysts said suggested to them that the analysis may have been conducted “at an earlier time point, such as week 24, versus the primary endpoint at week 48.”
They conceded that “Sjögren's disease drug development has been bogged down by high placebo response rates, making it difficult to achieve robust separation versus placebo” on the disease activity index underpinning argenx’s primary endpoint.
For its part, argenx said that once the study formally closes out and a database lock is in place, it plans to run a comprehensive analysis of the results “that may inform future research in Sjögren's disease.”
Prior to the study wind-down announcement, the William Blair team had been projecting $1.4 billion in peak sales in Vyvgart Hytrulo’s hoped-for Sjögren's indication.
The silver lining for argenx, however, is that even though that opportunity was “meaningful,” the analysts figure it wouldn’t have been as big as myositis—where Vyvgart Hytrulo posted a win in August—given potential Sjögren's competition on the way from Novartis and Amgen.
Argenx reported over the summer that the phase 2/3 Alkivia study of Vyvgart Hytrulo in autoimmune myositis had met its primary endpoint, with patients on the study drug hitting a 15.4-point greater improvement on an average measure of clinical efficacy at one-year versus placebo.
That trial looked at the myositis subtypes known as immune-mediated necrotizing myopathy (IMNM) and dermatomyositis (DM). At the time of the readout, analysts at Citi speculated that the data could portend peak U.S. sales of $1.9 billion for Vyvgart in IMNM alone.
Argenx has said it’s headed to regulators with the Alkivia data, which it also plans to present at an upcoming medical meeting.
News of the Sjögren's study conclusion came the same day as a reported win for a separate argenx asset, the anti-CD122 antibody FB102, in a midstage celiac disease trial. The molecule—which also scored a phase 1b vitiligo victory earlier this year—came to argenx by way of Forte Biosciences, which it acquired for $2.2 billion July.
As for Vyvgart, the drug, which won its flagship approval in generalized myasthenia gravis, has largely continued to live up to its expectations as the argenx’s chief pipeline-in-a-product. In its original form, the drug also carries an immune thrombocytopenia approval in Japan, and the below-the-skin Vyvgart Hytrulo holds a second indication in chronic inflammatory demyelinating polyneuropathy (CIDP) in the U.S. and multiple other territories.
While competition continues to mount in the myasthenia gravis space, Vyvgart has largely held its own, and last year helped reap product sales for argenx of $4.2 billion for all of 2025.