ABOUT ANTHRAX

INHALATIONAL ANTHRAX TREATMENT AND PREVENTION

Treatment

Hospitalization is warranted for all patients with suspected inhalational anthrax.¹⁰The CDC guidance for treatment is summarized here.

Antibiotics target Bacillus anthracis but have no direct effect on toxins that have been released, or the systemic damage they cause. Antitoxins are a class of FDA-approved drugs that complement antibiotics for anthrax treatment by preventing toxins from entering cells and exerting their deleterious effects.

Prevention

Pre-exposure prophylaxis

Currently, FDA-approved options for the pre-exposure prevention of anthrax include a vaccine and antitoxins (immediate prophylaxis only).

Post-exposure prophylaxis

For persons who may have been exposed to aerosolized B. anthracis spores but are not showing signs or symptoms of anthrax infection, recommended post-exposure prophylaxis includes antimicrobial therapy or vaccine administration combined with antimicrobial therapy. When alternative therapies are not available or appropriate, antitoxins can be used. In this situation, antitoxins would be expected to maintain their treatment effectiveness by preventing toxin formation.

References

Turnbull, PC. Anthrax in humans and animals, 4th ed. Geneva, Switzerland: World Health Organization. 2008.
Inglesby TV, O’Toole T, Henderson DA, et al. Anthrax as a biological weapon, 2002: updated recommendations for management. JAMA 2002;287:2236–52.
CDC Bioterrorism agents.https://fas.org/biosecurity/resource/documents/CDC_Bioterrorism_Agents.pdf. Accessed January 22, 2016.
University of Pittsburgh Medical Center. Center for Health Security. Anthrax Fact Sheet. Updated 02/26/2015. www.UPMCHealthSecurity.org. Accessed December 15, 2015.
Bower WA, Hendricks K, Pillai S, Guarnizo J, Meaney-Delman D. Clinical Framework and Medical Countermeasure Use During an Anthrax Mass-Casualty Incident. MMWR Recomm Rep. 2015 Dec 4;64(4):1-22. doi: 10.15585/mmwr.rr6404a1.
2015 Public Health Emergency Medical Countermeasures Enterprise Strategy and Implementation Plan. U.S. Department of Health and Human Services. https://www.phe.gov/Preparedness/mcm/phemce/Documents/2015-PHEMCE-SIP.pdf. Accessed January 13, 2016.
DSNS Fact Sheet. 2014. Accessed December 14, 2015.
Froude JW, Thullier P, Pelat T. Antibodies against anthrax: mechanisms of action and clinical applications. Toxins. 2011; 3(11):1433-1452.
IOM (Institute of Medicine). 2012. Prepositioning antibiotics for anthrax. Washington, DC: The National Academies Press.
Hendricks KA, Wright ME, Shadomy SV, Bradley JS, Morrow MG, Pavia AT, et al. Centers for Disease Control and Prevention expert panel meetings on prevention and treatment of anthrax in adults. Emerg Infect Dis [Internet]. 2014 Feb [Accessed December 14, 2015]. https://dx.doi.org/10.3201/eid2002.130687
Barr JR, Boyer AE, Quinn CP. Anthrax: modern exposure science combats a deadly, ancient disease. J Expo Sci Environ Epidemiol. 2010;20(7):573-4. doi: 10.1038/jes.2010.49.
Holty JE, Bravata DM, Liu H, et al. Systematic review: a century of inhalational anthrax cases from 1900 to 2005. Ann Intern Med 2006;144:270–80.
Jernigan DB, Raghunathan, PL, Bell, BP, et al. Investigation of bioterrorism-related anthrax, United States, 2001: epidemiologic findings. Emerg Infect Dis. 2002;8:1019-28.
Brookmeyer R, Johnson E, Barry S. Modelling the incubation period of anthrax. Stat Med. 2005;28:531–542.

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INDICATIONS AND USAGE AND IMPORTANT SAFETY INFORMATION

INDICATIONS AND USAGE

ANTHIM^® (obiltoxaximab) is indicated in adult and pediatric patients for the treatment of inhalational anthrax due to Bacillus anthracis in combination with appropriate antibacterial drugs. ANTHIM is indicated for prophylaxis of inhalational anthrax due to B. anthracis when alternative therapies are not available or are not appropriate.

LIMITATIONS OF USE

ANTHIM should only be used for prophylaxis when its benefit for prevention of inhalational anthrax outweighs the risk of serious hypersensitivity reactions and anaphylaxis.
The effectiveness of ANTHIM is based solely on efficacy studies in animal models of inhalational anthrax. It is not ethical or feasible to conduct controlled clinical trials with intentional exposure of humans to anthrax.
Safety and PK of ANTHIM have been studied in adult healthy volunteers. There have been no studies of safety or PK of ANTHIM in the pediatric population. A population PK approach was used to derive intravenous infusion dosing regimens that are predicted to provide pediatric patients with exposure comparable to the observed exposure in adults.
ANTHIM binds to the protective antigen (PA) component of B. anthracis toxin; it does not have direct antibacterial activity. ANTHIM is not expected to cross the blood-brain barrier and does not prevent or treat meningitis. ANTHIM should be used in combination with appropriate antibacterial drugs.

IMPORTANT SAFETY INFORMATION

WARNING: HYPERSENSITIVITY and ANAPHYLAXIS

Hypersensitivity and anaphylaxis have been reported during the intravenous infusion of ANTHIM. Due to the risk of hypersensitivity and anaphylaxis, ANTHIM should be administered in monitored settings by personnel trained and equipped to manage anaphylaxis. Monitor individuals who receive ANTHIM closely for signs and symptoms of hypersensitivity reactions throughout the infusion and for a period of time after administration. Stop ANTHIM infusion immediately and treat appropriately if hypersensitivity or anaphylaxis occurs.

WARNINGS AND PRECAUTIONS

Hypersensitivity reactions were the most common adverse reactions in the safety trials of ANTHIM, occurring in 34/320 healthy subjects (10.6%). Three (0.9%) cases of anaphylaxis occurred during or immediately after the infusion. In clinical trials, manifestations of anaphylaxis were rash/urticaria, cough, dyspnea, cyanosis, postural dizziness and chest discomfort. ANTHIM infusion was discontinued in 8 (2.5%) subjects due to hypersensitivity or anaphylaxis. The adverse reactions reported in these 8 subjects included urticaria, rash, cough, pruritus, dizziness, throat irritation, dysphonia, dyspnea and chest discomfort. The remaining subjects with hypersensitivity had predominantly skin-related symptoms such as pruritus and rash, and 6 subjects reported cough.

Premedication with diphenhydramine is recommended prior to administration of ANTHIM. Diphenhydramine premedication does not prevent anaphylaxis, and may mask or delay onset of symptoms of hypersensitivity.

ADVERSE REACTIONS

The safety of ANTHIM has been studied only in healthy volunteers. It has not been studied in patients with inhalational anthrax. The most frequently reported adverse reactions (occurred in >1.5% of healthy subjects) were headache, pruritus, infections of the upper respiratory tract, cough, vessel puncture site bruise, infusion site swelling, urticaria, nasal congestion, infusion site pain, and pain in extremity.

USE IN SPECIFIC POPULATIONS

Pregnancy
No adequate and well-controlled studies in pregnant women were conducted. Because animal reproduction studies are not always predictive of human response, ANTHIM should be used during pregnancy only if clearly needed.

Pediatric Use
There have been no studies of the safety or PK of ANTHIM in the pediatric population.

To see the complete prescribing information for ANTHIM, click here.