Advances since 2001 include FDA-approved anthrax antitoxins available now

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With most eyes on COVID-19, it would be prudent to remain vigilant for older threats at the same time

By Daniel R. Lucey MD, MPH, FIDSA

A major difference in treatment and prophylaxis for inhalational anthrax since the attacks of 2001 is the availability of three U.S. Food and Drug Administration approved antitoxins. Several key FDA and U.S. Centers for Disease Control information links are listed below to serve as updates for clinicians.

The latest (August, 2019) FDA list of all products approved for anthrax includes information on the three antitoxins, approved between 2012 and 2016,  appear in the links below. Two of the antitoxins are monoclonal antibodies: “Raxibacumab” and “Anthim” (“obiltoxaximab”), while one is a polyclonal antibody derived from vaccinated donors: “Anthrax Immune Globulin IV (AIGIV)”, or “Anthrasil.”

The U.S. Centers for Disease Control and Prevention guidance for the use of any of  these three antitoxins as treatment in persons even with a “high-level of clinical suspicion for systemic anthrax” is cited on page 15 (Box 5) of the Dec. 4 2015 CDC Morbidity and Mortality Weekly Report.

CDC Guidance for POST-EXPOSURE PROPHYLAXIS (PEP), using either of the two monoclonal antitoxins, is in this Dec. 13, 2019 MMWR: Obiltoxaximab and raxibacumab also have an indication for PEP of inhalation anthrax due to B. anthracis when alternative therapies are not available or are not appropriate. In these situations, obiltoxaximab or raxibacumab may be considered to help prevent inhalation anthrax. The predicted effectiveness of both antitoxins for this indication is based solely on efficacy studies conducted in animal models of inhalation anthrax (66,67). Data indicate that raxibacumab can be coadministered with AVA for PEP without affecting vaccine immunogenicity (68). No data are available to assess whether obiltoxaximab coadministered with AVA impairs vaccine immunogenicity. AIGIV does not have a PEP indication because coadministration of AIGIV and AVA in a rabbit model has been shown to significantly reduce the development of an immune response to AVA (68).”

Dr. Daniel Lucey

Daniel Lucey, MD, MPH, FIDSA, FACP, is a Clinical Professor of Medicine (Teaching) at Dartmouth Geisel School of Medicine, adjunct Professor at Georgetown Medical Center, senior scholar at Georgetown Law, Anthropology Research Associate at the Smithsonian Museum of Natural History and a member of the Infectious Diseases Society of America Global Health Committee. He served as a volunteer to outbreaks overseas including patient care in Sierra Leone and Liberia (MSF) during Ebola 2014, SARS 2003, MERS 2013, Plague 2017 as well as H5N1, Zika, and Yellow Fever. Since Jan. 6 he has contributed more than 50 posts to Science Speaks on COVID-19 and traveled to China Feb. 11. With career experiences, he proposed and helped design the 2018-2022 Smithsonian Exhibition on Epidemics.


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