argenx SE announced the publication of novel translational data from the open-label Phase 2 study of efgartigimod for the treatment of pemphigus that further support the potential role of FcRn blockade and potential of efgartigimod in autoimmune skin blistering disorders. The translational data, “FcRn Antagonism Leads to a Decrease of Desmoglein-Specific B Cells: Secondary Analysis of a Phase 2 Study of Efgartigimod in Pemphigus Vulgaris and Pemphigus Foliaceus” were published in the journal Frontiers of Immunology. The novel translational data, along with previously published translational data in Cells, will also be presented in a symposium at the Society for Investigative Dermatology (SID) Annual Meeting at 7:30am PT.

The complete results from the Phase 2 study of efgartigimod for the treatment of pemphigus. Pemphigus and BPare IgG-mediated autoimmune skin blistering diseases: In pemphigus, IgG autoantibodies against Dsg-1 and Dsg-3 cause acantholysis or disruption of keratinocyte adhesion; new data suggest role of additional non-desmoglein IgG autoantibodies in pemphigus pathophysiology; In BP, IgG autoantibodies against hemidesmosomal proteins (BP180 and BP230) at the dermal-epidermal junction drive pathophysiology of disease. In a secondary analysis of a subset of patients in the Phase 2 studyof efgartigimod in pemphigus: Efgartigimod treatment resulted in sustained reduction of antigen-specific B-cells in participants with pemphigus vulgaris (PV) and foliaceus, maintained following treatment cessation, and which correlated with sustained clinical improvement while total IgG returned to near baseline levels; Median CD19+ B-cells remained within normal limits at all timepoints measured, and no new safety signals were detected; No observed effect on total leukocytes, neutrophils, monocytes, or lymphocytes in patients treated with long-term efgartigimod therapy, however frequency of CD19+ B-cells in circulation was observed to decrease following efgartigimod treatment; Efgartigimod was shown to efficiently rescue the loss of keratinocyte adhesion upon anti-Dsg-3 antibodies (anti-Dsg3) and PV IgG treatment, indicating that stabilization of keratinocyte adhesion may present a novel treatment paradigm.