Argenx terminates Phase III Sjögren's trial while reporting positive Phase II celiac results

argenx (official website) announced that it will discontinue the Phase III UNITY trial of subcutaneous efgartigimod in Sjögren's disease after an independent monitoring committee concluded that the study could not meet its primary endpoint. The company reported no new safety signals and plans a comprehensive analysis after database lock. On the same day, argenx announced positive Phase II results for FB102, an investigational anti-CD122 antibody in celiac disease, reporting a statistically significant improvement in intestinal histology versus placebo (p=0.0176) and plans to advance the program into Phase III. Full datasets from both programs remain unavailable for independent assessment. argenx

This is particularly interesting because the company experienced two opposite clinical outcomes on the same day.

One validated therapeutic platform failed to demonstrate sufficient efficacy in a new indication, while a different mechanism produced encouraging early clinical evidence.

The failed program involves efgartigimod, an FcRn antagonist already successfully commercialized in other autoimmune diseases.

That creates a fundamental development question:

Does efficacy in one autoimmune condition justify expansion into another?

Not necessarily.

Sjögren's disease is biologically heterogeneous, and the Phase III study assessed systemic disease activity using clinESSDAI at Week 48.

The failure could reflect inadequate biological effect, patient heterogeneity, endpoint sensitivity, or combinations of these factors. The available announcement does not establish which explanation is correct.

Meanwhile, FB102's celiac results were obtained in a controlled gluten-challenge study using histological endpoints.

A positive histological result supports further investigation but does not yet establish durable real-world clinical benefit.