Initial phase I/II studies using the monoclonal antibody daratumumab have already revealed encouraging results in the treatment of multiple myeloma.[44] Daratumumab and SAR650984, another anti-CD38 antibody being investigated in clinical trials, induce strong antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity, but also seem to functionally interfere with CD38 signaling.[45,46]. Here, CD38 is linked to plasma cell myeloma.