Argenx’s Vyvgart (efgartigimod alfa-fcab) shows lengthy benefit for myositis and Sjögren’s disease, setting up its anticipated Phase III readouts.
The data presented at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, taking place in London from 3 to 6 June, has shown durability up to a year in myositis and 72 weeks in Sjögren’s disease.
Go deeper with GlobalData
Discover B2B Marketing That Performs
Combine business intelligence and editorial excellence to reach engaged professionals across 36 leading media platforms.
One-year data shows continued benefit of myositis
The ALKIVIA+ study (NCT05979441) is an ongoing open-label extension study that enrolled myositis patients who completed the 24-week, double-blind, placebo-controlled Phase II ALKIVIA trial (NCT05523167).
At 52 weeks, 37.5% of patients who had continuously received Vyvgart maintained their major Total Improvement Score (TIS) improvement from week 24. Of the patients who switched from placebo to Vyvgart at 24 weeks, 33.3% achieved a similar major TIS improvement. Rates of moderate TIS improvement were also similar between the groups, at 75.0% and 66.7%, respectively.
Patients receiving continuous Vyvgart saw a mean TIS of 52.19, while patients who switched from placebo achieved a mean TIS of 49.62, both at week 52.
TIS is a composite index based on six core set measures, including muscle strength, physician and patient global assessments of disease activity, physical function, enzyme levels, and extra-muscular activity. Higher TIS values reflect greater overall clinical improvement. Moderate and major improvement are defined as TIS ≥40 and ≥60, respectively.
The safety profile was consistent over the course of the study, with no increase in adverse events with longer exposure.
Myositis can cause serious and irreversible damage to muscles and organs, leading to a loss of independence and a significant burden for patients. Sjögren’s disease can cause dry eyes and mouth, chronic fatigue, and joint pain. It can also affect multiple organ systems and lead to nervous system complications.
Dr Hector Chinoy, presenting study author and Professor of Rheumatology and Neuromuscular Disease at the University of Manchester, said: “Patients with autoimmune myositis face the serious challenge that their immune system attacks their own body, causing irreversible muscle loss, weakness, pain and reduced quality of life, while the limited available treatments can carry significant side effects and be difficult to tolerate long term.”
A Phase III trial for Vyvgart in myositis is ongoing, with topline results expected in Q3 2026.
Vyvgart durability in Sjögren’s disease
The RHO+ study (NCT06203457) is a 48-week open-label extension study that evaluated patients with Sjögren’s disease who continued to receive Vyvgart, and those who transitioned from placebo to Vyvgart after completing the 24-week double-blind treatment period of the Phase II RHO study (NCT05817669).
At week 72, median ClinESSDAI scores were low in both groups: 2.5 in the efgartigimod arm and 2.0 in patients who transitioned from placebo to efgartigimod. Low disease activity is indicated by a ClinESSDAI score of <5.
Vyvgart was well tolerated, with no new safety signals identified following long-term use in participants with Sjögren’s disease.
Sjögren’s disease is a chronic autoimmune disorder. The immune system mistakenly attacks healthy cells in the glands that produce moisture, primarily the tear and saliva glands.
The Phase III UNITY trial is currently ongoing to assess the efficacy and safety of efgartigimod in patients with moderate to severe Sjögren’s disease. Topline results are expected in the second half of 2027.
Vyvgart first gained approval from the US Food and Drug Administration (FDA) for generalised myasthenia gravis (gMG) in 2021. Since then, Argenx has developed a subcutaneous version of the drug, Vyvgart Hytrulo (efgartigimod alfa and hyaluronidase-qvfc). It is a first-in-class antibody fragment that blocks the neonatal Fc receptor (FcRn) to reduce circulating IgG autoantibodies.
