Efgartigimod - (ALKIVIA)

June 3, 2026: argenx SE (Euronext & Nasdaq: ARGX) announced new VYVGART (efgartigimod; IV and SC/“Hytrulo”) data across autoimmune rheumatic diseases to be presented at EULAR 2026 (June 3–6, 2026; London).

Myositis (Phase 2 ALKIVIA / OLE ALKIVIA+): Interim ALKIVIA+ analysis through Week 52 in patients continuing efgartigimod or switching from placebo showed sustained functional improvement by Total Improvement Score (TIS). At Week 52, major TIS improvement was maintained by 37.5% of continuous-treatment patients and achieved by 33.3% of switch patients; moderate improvement rates were 75.0% and 66.7%, respectively. Mean TIS at Week 52 was 52.19 (continuous) and 49.62 (switch). Safety remained consistent with no increase in adverse events with longer exposure. Phase 3 ALKIVIA topline results are expected in Q3 2026.

Sjogren’s disease (Phase 2 RHO / OLE RHO+): In RHO+, patients switching to biweekly dosing maintained response on clinical measures; placebo-to-efgartigimod switch patients improved in ClinESSDAI and increased CRESS response. At Week 72, median ClinESSDAI was 2.5 (efgartigimod arm) and 2.0 (switch), indicating low disease activity; no new safety signals. Phase 3 UNITY is ongoing, with topline results expected in 2H 2027.

Cross-indication safety: Across 834 treated patients and >1,300 patient-years, efgartigimod was consistently well tolerated (including myositis, Sjogren’s, and lupus nephritis), with mostly mild-to-moderate adverse events and no higher event rates with longer duration.