Hypersensitivity and Anaphylaxis

Hypersensitivity reactions including rash, urticaria, pruritus, chills, chest and throat tightness, lip and throat swelling, and hypotension were reported in 27 (4.5%) of 606 healthy subjects during or after the administration of raxibacumab in clinical trials. Two subjects experienced anaphylaxis during the raxibacumab infusion [see Adverse Reactions ( 6.1)] .

Some subjects with hypersensitivity or anaphylaxis required interruption or discontinuation of the raxibacumab infusion as well as additional appropriate treatment that included steroids, diphenhydramine, H2 blockers, and/or intravenous fluids [see Adverse Reactions ( 6.1)] .

Due to the risk of anaphylaxis, administer raxibacumab injection in monitored settings where appropriate equipment, medication (including epinephrine) and personnel trained to manage hypersensitivity, anaphylaxis, and shock are available. Monitor patients closely during the infusion and for a period of time after administration. If hypersensitivity reactions or anaphylaxis occur, interrupt or stop the raxibacumab infusion immediately and treat appropriately.

Pre-medicate with diphenhydramine within 1 hour prior to administering raxibacumab to reduce the risk of occurrence and/or severity of a hypersensitivity reaction [see Dosage and Administration ( 2.1), Adverse Reactions ( 6.1)] . Diphenhydramine premedication does not prevent anaphylaxis and may mask or delay the onset of symptoms of hypersensitivity.