GPNMB and osteosarcoma: Preclinical studies of glembatumumab vedotin (CDX-011), an antibody-drug conjugate with the combination of anti-GPNMB antibody and monomethyl auristatin E (vedotin), suggested an antitumor effect [43,44], but in the prospective phase II trial (AOST1521), osteosarcoma patients achieved only limited responses to glembatumumab vedotin (of the 22 patients enrolled, an objective response was observed in only one patient) [45].