narnatumab narnatumab narnatumab is a human monoclonal antibody designed for the treatment of cancer. clinical development was abandoned after phase i trials. narnatumabmonoclonal antibodytypewhole antibodysourcemousetargetmst1r (aka ron)clinical dataatc codenoneidentifierscas number1188275-92-4 nchemspidernoneuniir42yk40u9mkeggd10074chemical and physical dataformulac6454h10026n1754o2020s44molar mass145922.10 g·mol−1 ny (what is this?) (verify) narnatumab was developed by imclone systems.