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NCT Number: NCT07478471

Observational Study of Raxibacumab in Sporadic Cases of Systemic Anthrax

This observational, open-label, single arm, study is designed such that it may be implemented for any individual with a lab confirmed sporadic case of systemic anthrax disease treated with raxibacumab outside of the current United States Prescribing Information (USPI). Systemic anthrax cases may include inhalational, gastrointestinal and injectional anthrax, anthrax meningitis or bacteremia or cutaneous anthrax with systemic effects.

This study is designed to evaluate the clinical effectiveness (including course of illness and survival), safety profile and pharmacokinetic (PK) analysis of raxibacumab from patients who are treated with raxibacumab as part of their clinical care following exposure to B. anthracis. Study data, PK sample provision/collection and other investigational research will be collected prospectively to the extent possible at pre-specified time points. However, there is no reasonable way to identify prospectively the individuals likely to become eligible for participation in this study so most data in this study is anticipated to be collected retrospectively. Scavenged blood samples will be utilized where possible to maximize sample analyses and other investigational parameters. Therefore, both retrospective and prospective data collection are allowed in this protocol in order to maximize the amount of information obtained in subjects who have been administered raxibacumab. This field study will be the first opportunity to collect data on B. anthracis-exposed patients treated with raxibacumab, to better understand the clinical benefit and safety of the drug and to further inform patient care and treatment choices for management of anthrax.

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Key information

Conditions

Infections, Bacterial Anthrax Bacillaceae Infections Bacterial Infections Bacterial Infections and Mycoses Gram-Positive Bacterial Infections Infections

Sex eligibility

All sexes

Study type

Observational

About this study

The protocol is a post-marketing requirement from the FDA to evaluate the clinical benefit, safety and pharmacokinetic analysis of raxibacumab administered to patients with lab confirmed systemic anthrax disease as part of their medical care following exposure to Bacillus anthracis.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Any patient (women, including pregnant and lactating women, men, and children of all ages) with lab confirmed systemic anthrax in the US treated with a dose of raxibacumab from the Strategic National Stockpile (SNS).
  • Patients willing and able to adhere to the procedures stated in the protocol.
  • Patients (or legally acceptable representative of minors and unconscious adults) willing and able to give written informed consent/assent (as applicable) to participate in the study.

Note: Systemic anthrax is defined in this protocol 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: Epidemiological link to a documented anthrax environmental exposure and/or laboratory test used for confirmation of systemic anthrax diagnosis by one of the following:

  • Isolation and culture of Bacillus spp. from an affected tissue or site;
  • Evidence of Bacillus spp. DNA by PCR in biological samples such as blood or cerebrospinal fluid (CSF) or lesion of affected tissue (skin, pulmonary, reticuloendothelial, or gastrointestinal);
  • Molecular Typing by Multiple-Locus Variable number tandem repeat Analysis (MLVA); Susceptibility to lysis by γ-phage;
  • QuickELISA™ Anthrax-PA Kit- Detection of anti-PA antibodies in serum, plasma, or pleural/ascitic fluid or;
  • RedLine Alert™ Test- Qualitative identification of B. anthracis colonies

Exclusion criteria

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

Treatment and study plan

Collection of samples

Biological

Whenever possible serum samples will be collected from all subjects to determine serum raxibacumab concentrations pre-infusion, and at specific timepoints post-infusion. In the event cerebrospinal fluid (CSF), pleural, ascites, or bronchoalveolar lavage (BAL) fluid are collected for ad hoc clinical laboratory testing, any remaining excess sample will be provided to Sponsor for determination of raxibacumab concentrations.

Any available serum remaining from ad hoc clinical laboratory specimen collections prior to raxibacumab administration will be provided to Sponsor for measurement of serum PA concentrations. In addition, remaining post raxibacumab dose serum specimens may also be analyzed for lethal factor (LF) levels.

Primary outcomes

  1. Clinical Benefit of Raxibacumab for Patients with Confirmed Systemic Anthrax Disease

    Time frame: Up to Day 29

    The primary objective is:

    To evaluate the clinical benefit in patients with confirmed systemic anthrax disease, as assessed by overall mortality rate up to Day 29.

  2. Clinical Benefit of Raxibacumab for Patients with Confirmed Systemic Anthrax Disease

    Time frame: Up to Day 29

    The primary objective is:

    To evaluate safety of raxibacumab in patients with confirmed systemic anthrax disease, as assessed by incidence of ADRs.

  3. Clinical Benefit of Raxibacumab for Patients with Confirmed Systemic Anthrax Disease

    Time frame: Up to Day 29

    The primary objective is:

    To evaluate safety of raxibacumab in patients with confirmed systemic anthrax disease, as assessed by incidence of SAEs.

Secondary outcomes

  1. To evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease

    Time frame: Up to Day 29

    The secondary objective is to evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease assessed by Incidence of hospitalization

  2. To evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease

    Time frame: Up to Day 29

    The secondary objective is to evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease assessed by length of hospitalization

  3. To evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease

    Time frame: Up to Day 29

    The secondary objective is to evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease assessed by length of ICU stay.

  4. To evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease

    Time frame: Up to Day 29

    The secondary objective is to evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease assessed by duration of mechanical ventilation

  5. To evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease

    Time frame: Up to Day 29

    The secondary objective is to evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease assessed by incidence of ICU stay

  6. To evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease

    Time frame: Up to Day 29

    The secondary objective is to evaluate the clinical course of the disease in patients with confirmed systemic anthrax disease assessed by incidence of mechanical ventilation

Other outcomes

  1. Anti-PA serum concentrations

    Time frame: Up to Day 29

    Assess anti-PA serum concentrations to the extent that data permit.

  2. Anthrax toxin levels

    Time frame: Up to Day 29

    Assess anthrax toxin levels to the extent that data permit.

  3. Raxibacumab PK in Relation to Anthrax Toxemia

    Time frame: Up to Day 29

    Inform on raxibacumab PK parameter of Cmax, in relation to anthrax toxemia to the extent that the data permit.

  4. Raxibacumab PK in Relation to Anthrax Toxemia

    Time frame: Up to Day 29

    Inform on raxibacumab PK parameter of AUC0-inf, in relation to anthrax toxemia to the extent that the data permit.

  5. Raxibacumab PK in Relation to Anthrax Toxemia

    Time frame: Up to Day 29

    Inform on raxibacumab PK parameter of AUClast, in relation to anthrax toxemia to the extent that the data permit.

  6. Raxibacumab PK in Relation to Anthrax Toxemia

    Time frame: Up to Day 29

    Inform on raxibacumab PK parameter of terminal phase elimination half-life, in relation to anthrax toxemia to the extent that the data permit.

Study contacts

Contact information is provided by the study sponsor or research team.

Clinical Development Representative

CONTACT

[email protected]

(204) 275-4196

Sponsors and collaborators

Lead sponsor

Emergent BioSolutions

Industry

Collaborators

  • Centers for Disease Control and Prevention
  • Department of Health and Human Services

Registry information

Official study title

An Observational Clinical Study of Raxibacumab Use in Sporadic Cases of Systemic Anthrax

Important dates

Study start
2027
Primary completion
2030
Study completion
2030
First posted
Mar 17, 2026
Registry last updated
Mar 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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