SLN124 is a GalNac-siRNA targeting transmembrane serine protease 6 (Tmprss6). SLN124 is composed of a trimeric GalNAc ligand conjugated to TMPRSS6‐siRNA. SLN124 has the potential for an siRNA to restore hepcidin expression and normalise iron homeostasis in β‐thalassaemia.