Annual Report 2025

Annual Report 2025

efgartigimod (ARGX-113) Development

Mechanism of Action

As shown in Figure 1, efgartigimod is a human IgG1 Fc fragment equipped with our ABDEG™ mutations that is designed to target the FcRn and reduce IgG. FcRn is foundational to the immune system and functions to recycle IgG, extending its serum half-life over other IgGs that are not recycled by FcRn. IgGs that bind to FcRn are rescued from lysosomal degradation. By binding to FcRn, efgartigimod can reduce IgG recycling and increase IgG degradation.

Efgartigimod’s mechanism of action (graphic)
Figure 1: efgartigimod’s mechanism of action blocks the recycling of IgG antibodies and removes them from circulation. FcRn, neonatal Fc receptor; Ig, immunoglobulin; LDL, low-density lipoprotein.
1) Ulrichts P, et al. J Clin Invest. 2018;128:4372–86
6) Roopenian DC, Akilesh S. Nat Rev Immunol. 2007;7:715–25.
7) Ward ES, Ober RJ. Trends Pharmacol Sci. 2018;39:892–904.

Formulations

Overview

We are developing two formulations of efgartigimod to address the needs of patients, physicians, and payers across indications and geographies, including efgartigimod IV (VYVGART) and efgartigimod SC (VYVGART SC).