Anthrax Vaccine Clinical Trials
Condition: Anthrax
MeSH terms: Anthrax
Study type: Interventional
Phase: Phase 1

Summary: 
      This study will examine the recombinant, that is, produced by genetic engineering, protective
      antigen (rPA) that brings about antibodies to neutralize the anthrax toxin and that could
      therefore be predicted to offer protection against anthrax. Today, anthrax is rarely
      encountered in the United States, since the introduction of vaccines for cattle in the 1930s.
      A human vaccine was licensed in 1970. Vaccination against anthrax has been confined to people
      at risk, such as wool sorters and some veterinarians. However, the rising prospects of B.
      anthracis being used as a weapon have led to routine administration of the anthrax vaccine to
      members of the armed forces.

      Adults who are in good health may be eligible for this study. The involvement of 300 adults
      is planned.

      Participants will have a general physical exam and test for vital signs. There will also be
      collection of blood for chemistry and hematology; urinalysis; tests for HIV, hepatitis B and
      C, and liver function; and a pregnancy test, if applicable.

      On a random basis, patients will receive one of the rPA formulations. Two doses of rPA will
      be evaluated, 10 microgram ((Micro)g) and 20 (Micro)g. This evaluation aims to establish the
      safety and most desirable level of dosage. Patients will receive one injection of the
      vaccine, administered in the left shoulder or left thigh. About 30 minutes later, their
      temperature will be taken, and the injection site will be inspected. Rare but severe
      reactions could occur if there is extreme sensitivity to a vaccine. However, such an
      occurrence is extremely rare following a vaccine, and if there are any dangerous symptoms,
      they can be effectively treated by medications available to patients while they are at the
      clinic. If there are no significant abnormal results, patients may return home. About 6 hours
      later and daily for 7 days, they will take their temperature and examine the injection site.
      The vaccine may cause temporary discomfort at the site of injection, and participants may
      experience a mild fever for 1 or 2 days after vaccination.

      Patients will receive diary cards, a digital thermometer, and instructions on taking their
      temperature and measuring redness and swelling at the injection site, as well as for
      recording aches, muscle pain, or sensitivity to light for 7 days. They will be examined at
      the clinic at 72 hours following vaccination and also on the 7th day if they have a fever at
      or above 100.4 , if swelling is at or more than 2 inches, or if they request an exam.
      Meanwhile, a clinic staff member will call patients and discuss the findings. Then patients
      will receive a second and third injection of the same vaccine at 2-month intervals. There
      will also be interviews about patients' health at each visit to the clinic, plus monitoring
      of the vaccination after 6 hours and for 7 days. One year later, patients will receive a
      fourth injection of the same vaccine.

      Direct benefit to participants in this study is not guaranteed, although an antibody response
      is predicted. The results in this study will help in the development of improved vaccines for
      anthrax.
    

Detailed description: 
      Anthrax is rarely encountered in the U.S. since the introduction of attenuated vaccines for
      cattle in the 1930's. A vaccine for humans, composed of a cell-free preparation absorbed onto
      alum, was licensed in 1970 after successful clinical trials. Vaccination against anthrax in
      the U.S. was confined to individuals at risk such as wool sorters and some veterinarians
      until the prospects were raised of B. anthracis being used as a weapon after the Iraq war.
      Now anthrax vaccine is administered routinely to the armed forces. Interest in improving this
      vaccine was stimulated by the use of B. anthracis spores for bioterrorism.

      The active component of the investigational vaccine is called the protective antigen. When B.
      anthracis invades the host tissues, the protective antigen activates two other proteins to
      form anthrax toxin. The symptoms of anthrax are caused by this toxin. Alone, the protective
      antigen has no known toxicity. The gene for this protein has been isolated and changed
      specifically to improve its properties as a vaccine-this recombinant protective antigen (rPA)
      elicits antibodies that neutralize the anthrax toxin and, thereby, can be predicted to confer
      protection.

      This is the first study of our investigational rPA vaccine in humans. The broad objectives
      are to characterize the safety and serum antibody levels of different doses and formulations
      of rPA in comparison to the licensed anthrax vaccine, AVA.
    

Intervention name(s): Anthrax Vaccine; Blood Chemistry; Hematology; Urinalysis
Intervention type(s): Drug; Procedure; Procedure; Procedure
Primary purpose: Treatment
Keywords: PA; Phase I; Phase 2; Safety; Immunogenicity