Glembatumumab vedotin consists of an antibody (a type of human protein) attached to a drug called Monomethyl Auristatin E (MMAE) that can kill cancer cells. Glembatumumab vedotin is intended to work by specifically directing the drug to the cancer cell. It attaches to a molecule on the cancer cell called gpNMB, and then releases the MMAE inside the tumor cell, which in turn causes the cell to die.