 The most commonly observed adverse events are headaches, upper respiratory tract infection, nausea, pain in extremity and pruritus skin itching.Raxibacumab injection is a monoclonal antibody targeting the protective antigen (PA) component of the lethal toxin of Bacillus anthracis.Raxibacumab was developed by Human Genome Sciences (HGS) in conjunction with the U.S. Department of Health and Human Services (HHS) under contract number HHS010020050006C.