Design: Phase III, multicentre, randomised (2:1), double-blind, placebo-controlled
Population: 222 adults with moderate-to-severe pemphigus (190 vulgaris, 32 foliaceus), all on prednisone 0.5 mg/kg
Primary outcome: Complete remission on ≤10 mg prednisone for ≥8 weeks by week 30 (pemphigus vulgaris)
Effect: 35.5% vs 30.3%; OR 1.19 (95% CI 0.60-2.41); P = 0.60

ADDRESS was a global phase III, double-blind trial (British Journal of Dermatology, 19 October 2026). It randomised 222 adults with newly diagnosed or relapsing moderate-to-severe pemphigus 2:1 to weekly subcutaneous efgartigimod, a neonatal Fc receptor blocker that lowers circulating IgG, or placebo. Everyone started prednisone at 0.5 mg/kg daily.

In pemphigus vulgaris, complete remission on 10 mg prednisone or less, sustained for at least eight weeks by week 30, was reached by 35.5% with efgartigimod and 30.3% with placebo (OR 1.19, 95% CI 0.60-2.41). Total steroid use was similar. Efgartigimod rapidly lowered total IgG and anti-desmoglein 1 and 3 antibodies, but disease activity scores did not improve more than with placebo. Serious adverse events were similar (12.2% vs 13.3%) and there were no deaths.

The trial is a reminder that lowering a pathogenic antibody does not guarantee clinical benefit. For now, efgartigimod has no role in routine pemphigus care, and rituximab with corticosteroids remains the evidence-based first-line approach.

Do not add efgartigimod to steroids for pemphigus outside a trial; it did not improve remission.
Keep rituximab plus a corticosteroid as first-line for moderate-to-severe pemphigus.
Do not use falling desmoglein antibody titres alone as proof a new agent is working.
Plan steroid tapering and bone protection from the start, whatever the steroid-sparing agent.

Why it matters

It challenges the assumption that any drug that lowers pemphigus autoantibodies will translate into faster remission.

The statistics, in plain English

An odds ratio of 1.19 with a CI from 0.60 to 2.41 means the trial cannot exclude harm or a modest benefit, but it found no clear effect. Antibody falls are a surrogate; the clinical endpoint is what counts.