Mapatumumab (or anti TRAIL-R monoclonal) is an anticancer monoclonal. Its mode of action is very original : it activates a cell receptor that induces cellular death (apoptosis). It is an agonistic monoclonal, and not an antagonistic one. The receptor to which it binds is the TRAIL (TNF receptor apoptosis induced ligand) receptor. This monoclonal activates the receptor (TRAIL-R) even better than the physiological activator (TRAIL).