The Recycling Antibody® is engineered so that a single antibody molecule can bind to an antigen multiple times, in contrast to conventional antibodies, which can only bind to the antigen once. Once conventional antibodies bind to a membrane anchored antigen such as a cytokine receptor, the antibody-antigen complex is internalised and degraded within the lysosome. This results in a shorter plasma half-life of the therapeutic antibody, necessitating frequent administration of the antibody drug or at higher doses to sustain efficacious plasma antibody concentration. Chugai’s proprietary SMART-Ig Recycling Antibody technology overcomes this problem by engineering the antibody to dissociate from the antigen at acidic pH within the endosome. Once dissociated, the recycling antibody is free to bind to the FcRn (neonatal Fc Receptor) within the endosome, which transports the antibody back into circulation to bind to more antigen.