AMSTERDAM, Netherlands, June 3, 2026
argenx presented new clinical data at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress demonstrating that efgartigimod (VYVGART®) continues to deliver long-term clinical benefits and a consistent safety profile in patients with myositis and Sjogren’s disease. The findings, derived from the ongoing ALKIVIA+ and RHO+ extension studies, reinforce the therapeutic potential of FcRn blockade in autoimmune rheumatic diseases and support ongoing late-stage development programs. The company also highlighted cross-indication safety data involving more than 834 treated patients and over 1,300 patient-years of follow-up, further validating the drug’s favorable risk-benefit profile.
Long-Term Myositis Data Show Durable Functional Benefits
Results from the ALKIVIA+ open-label extension study demonstrated sustained improvements in patients with autoimmune myositis who received efgartigimod treatment for up to 52 weeks. Among patients who continuously received therapy, 37.5% maintained major improvement based on Total Improvement Score (TIS), while 75% maintained moderate improvement. Patients who switched from placebo to efgartigimod achieved comparable outcomes, with 33.3% reaching major improvement and 66.7% achieving moderate improvement. Mean TIS values remained clinically meaningful at Week 52, reaching 52.19 in continuously treated patients and 49.62 among those who transitioned from placebo. Importantly, long-term treatment showed no increase in adverse events, supporting sustained use in this chronic and debilitating disease. These findings strengthen evidence that pathogenic autoantibodies play a key role in myositis and that FcRn inhibition may provide meaningful disease control.
Sjogren’s Disease Study Supports Maintenance of Response
Data from the RHO+ extension study demonstrated that patients with Sjogren’s disease maintained therapeutic responses even after transitioning to a biweekly dosing schedule of efgartigimod. Patients originally treated with efgartigimod preserved low disease activity scores and stable clinical responses, while patients switching from placebo experienced significant improvements in disease activity and response measures. At Week 72, median ClinESSDAI scores remained low at 2.5 among continuous treatment recipients and 2.0 among patients transitioning from placebo, both well below the threshold indicating active disease. The therapy continued to demonstrate a favorable tolerability profile with no new safety signals, supporting its potential as a disease-modifying treatment option in a condition that currently lacks FDA-approved therapies targeting underlying disease mechanisms.
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Broad Safety Profile Reinforces FcRn Blockade Strategy
argenx also presented a comprehensive cross-study safety analysis evaluating efgartigimod across multiple autoimmune diseases, including myositis, Sjogren’s disease, and lupus nephritis. The analysis demonstrated a consistent safety profile across diverse patient populations and administration methods, with most adverse events reported as mild to moderate in severity. No increased rates of adverse events were observed with longer treatment durations. The company noted that these findings further validate the FcRn blockade approach and support broader investigation of efgartigimod across autoimmune rheumatic diseases. Additional development efforts include the ongoing Phase 3 ALKIVIA study in myositis, with topline results expected in the third quarter of 2026, and the Phase 3 UNITY trial in Sjogren’s disease, with results anticipated in the second half of 2027. Together, these programs position efgartigimod as a potentially important treatment option across multiple severe autoimmune conditions.
Source: argenx press release
