argenx: Efgartigimod shows sustained myositis benefit, maintained response in Sjogren’s with consistent safety
- At Week 52, 37.5% of patients continuously on efgartigimod maintained major TIS (≥60) and 33.3% of placebo‑switch patients achieved major TIS.
- Mean TIS at Week 52 was 52.19 for continuous treatment and 49.62 for placebo→efgartigimod patients.
- In RHO+, median ClinESSDAI at Week 72 was 2.5 for the efgartigimod arm and 2.0 for placebo→efgartigimod, and switching to biweekly dosing maintained clinical response.
- Cross‑indication safety analysis covered 834 treated patients and >1,300 patient‑years, reporting predominantly mild‑to‑moderate adverse events and no new safety signals.
Event and scope
argenx presented longitudinal data for efgartigimod at EULAR 2026 (June 3–6) covering myositis (ALKIVIA/ALKIVIA+) and Sjogren’s disease (RHO/RHO+), plus a cross‑indication safety analysis.
Myositis — ALKIVIA+
An interim Week 52 analysis of the open‑label ALKIVIA+ extension (participants from the 24‑week Phase 2 ALKIVIA trial) found sustained, clinically meaningful Total Improvement Score (TIS) gains: mean TIS 52.19 for continuous efgartigimod and 49.62 for patients who switched from placebo. At Week 52, 37.5% of continuous‑treatment patients maintained major improvement (TIS ≥60) versus 33.3% of switchers; moderate improvement rates were 75.0% and 66.7% respectively. Safety remained consistent over longer exposure.
Sjogren’s disease — RHO+
The 48‑week open‑label RHO+ extension showed that patients switching to biweekly dosing maintained clinical response, while placebo→efgartigimod patients improved on ClinESSDAI and CRESS. At Week 72 median ClinESSDAI scores were low (2.5 and 2.0), indicating low disease activity, with no new safety signals reported.
Safety and next milestones
A pooled safety review across autoimmune indications covered 834 treated patients and over 1,300 patient‑years and reported predominantly mild‑to‑moderate adverse events without signal emergence. Topline Phase 3 ALKIVIA results are expected Q3 2026; UNITY Phase 3 Sjogren’s topline is expected in H2 2027.
Source: argenx