ontuxizumab ontuxizumab ontuxizumab is a humanized rabbit monoclonal antibody designed for the treatment of cancer. it binds to endosialin (tem1 or cd248). ontuxizumabmonoclonal antibodytypewhole antibodysourcechimeric/humanized hybrid (mouse/human)targettem1clinical dataatc codenoneidentifierscas number946415-62-9chemspidernoneunii0m2xt000ycchemical and physical dataformulac6532h10050n1726o2054s44molar mass147034.92 g·mol−1 phase i trials are complete and the drug was granted orphan drug status by the fda for sarcoma. it is currently in phase ii trials for melanoma, colorectal cancer, sarcoma, and lymphoma. this drug was developed by morphotek and ludwig institute for cancer research.