Table 1.

Antitoxins Evaluated in the United States Government–Funded Pre- and Postlicensure Studies

Generic Name	Study Sponsora	Product Name/Brand Name	Also Known As	FDA Approval	Manufacturer	Description	Mechanism of Action
Raxibacumab	NIH/BARDA	…	…	2012	Emergent Biosolutions	…	Prevents binding of PA to anthrax toxin receptor, disrupting formation of the PA heptamer plasma membrane pore, impeding internalization of LT and ET [13]
Obiltoxaximab	NIH/BARDA	Anthim	…	2016	Elusys Therapeutics	…	Prevents binding of PA to anthrax toxin cellular receptors, preventing formation of the PA plasma membrane pore and blocking internalization of lethal factor and edema factor [14]
AIGIV	BARDA	Anthrasil	…	2015	Emergent Biosolutions	Purified human immune globulin from BioThrax-vaccinated donors	Toxin-neutralizing antibodies directed at PA; act by preventing or impeding internalization of LT and ET [15, 16]
AIGIV	NIH	Anthrivig	…	…	Emergent Biosolutions	Purified human immune globulin from BioThrax-vaccinated donors	Toxin-neutralizing antibodies directed at PA; act by preventing or impeding internalization of LT and ET [15, 16]
...	NIH	Valortim	MDX-1303	…	Pharmathene, Inc.	…	Tethers PA, free or bound, to a cell surface receptor, impeding attachment to the anthrax toxin receptor and internalization [17]
...	NIH	…	AVP-21D9	…	Emergent Biosolutions	…	Binds to PA63 and disrupts formation of the heptamer pore [18, 19]

Abbreviations: AIGIV, anthrax immunoglobulin intravenous; BARDA, Biomedical Advanced Research and Development Authority; ET, edema toxin; FDA, United States Food and Drug Administration; LT, lethal toxin; NIH, National Institutes of Health; PA, protective antigen.

^aThe NIH sponsored the prelicensure studies and BARDA sponsored the postlicensure studies.