This study will evaluate safety and clinical benefit of AIGIV used for treatment of patients with systemic anthrax. The study is designed to collect information on safety, clinical benefit (such as extent of anthrax illness and survival) and serum concentrations of AIGIV (for AIGIV pharmacokinetics) and anthrax toxins from sporadic cases of systemic anthrax patients treated with AIGIV.

This study is a post-marketing requirement from the FDA to evaluate safety and clinical benefit of AIGIV administered to systemic anthrax patients as part of their medical care after exposure to Bacillus anthracis (anthrax exposure can be via inhalation, ingestion, injection). Study information (i.e. data on safety and clinical benefit evaluation of AIGIV up to Day 30 following administration) and patient samples (for assessment of AIGIV pharmacokinetics and anthrax toxin levels) will be collected (up to Day 7 following AIGIV administration) prospectively to the extent possible; however, in some cases data may be collected retrospectively (including scavenged patient samples for assessment of serum AIGIV concentration and anthrax toxin levels). Therefore, both prospective and retrospective data collection are allowed in this study to maximize the amount of information obtained from systemic anthrax patients who have been treated with AIGIV.

Inclusion Criteria:

• Confirmed or suspected systemic anthrax patients in the USA or other jurisdictions (if feasible) treated with AIGIV provided by the Centers for Disease Control and Prevention (CDC).
• Systemic anthrax defined as a clinically compatible case of gastrointestinal, injectional, or inhalational anthrax; anthrax meningitis or bacteremia; or cutaneous anthrax with systemic effects (i.e. tachycardia, tachypnea, hypotension, hyperthermia, hypothermia, leukocytosis) or with lesions that involve the head, neck or upper torso, or are large, bullous, multiple, or surrounded by significant edema PLUS confirmation by one of the following:

Epidemiologically linked to a documented anthrax environmental exposure. Laboratory confirmation by isolation of B. anthracis from an affected tissue or site.

Demonstration of B. anthracis antigens in tissues by immunohistochemical staining using both B. anthracis cell wall and capsule monoclonal antibodies.

Evidence of B. anthracis DNA; for example, by polymerase chain reaction (PCR) in specimens collected from a normally sterile site (such as blood or cerebrospinal fluid (CSF)) or lesion of other affected tissue(s) (skin, pulmonary, reticuloendothelial, or gastrointestinal).

QuickELISA™ Anthrax-PA kit manufactured by Immunetics, Inc. for detection of anti-PA antibodies in serum, plasma, and pleural/ascitic fluid.

RedLine Alert™ test manufactured by Tetracore, Inc., for identification of B. anthracis colonies.

• Informed consent/assent (as applicable).

Exclusion Criteria:

• There are no exclusion criteria for subjects enrolling in this study.

Anthrax patients who have received AIGIV.