STSA-1301

STSA-1301 is a recombinant anti-human FcRn (neonatal Fc receptor) humanized IgG4 monoclonal antibody developed for the treatment of autoimmune diseases mediated by pathogenic IgG autoantibodies, such as idiopathic thrombocytopenic purpura (ITP). By specifically binding to the neonatal Fc receptor (FcRn), it blocks the recycling of IgG antibodies, leading to their accelerated degradation. This mechanism selectively reduces circulating pathogenic IgG without affecting other immunoglobulin classes like IgM or IgA. The drug is administered subcutaneously and is currently in clinical development with trials conducted primarily in China[1][2][3][5].