Clinical Trial: Immunogenicity and Safety Study of a Three-Dose BioThrax® Regimen for Post-Exposure Prophylaxis in Healthy Adults

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Immunogenicity and Safety Study of a Three-Dose BioThrax® Regimen for Post-Exposure Prophylaxis in Healthy Adults

Brief Summary:

The purpose of this Phase 3 clinical trial is to evaluate the immunogenicity and safety of BioThrax anthrax vaccine in healthy adults following 3 doses of BioThrax. Results of this study will be used to support a post-exposure prophylaxis (PEP) indication for BioThrax.

This study will be conducted in the United States (U.S.), in 200 healthy male and female volunteer subjects ages 18 to 65 years.

The duration of study participation for each individual subject will be approximately 128 days (4.25 months), including a screening period of approximately 28 days followed by 100 days on study.

Detailed Summary: BioThrax® (also called Anthrax Vaccine Adsorbed or AVA) is the only FDA-licensed vaccine for the prevention of anthrax infection. This study will evaluate the immunogenicity of the vaccine using a post-exposure vaccination schedule. Correlations will be drawn to immunogenicity and survival data from animal models to demonstrate that BioThrax® can elicit a protective immune response for PEP.
Sponsor: Emergent BioSolutions

Current Primary Outcome: Percentage of Subjects Achieving a TNA Response of a Predefined Threshold Value at Day 63 (5 Weeks Following the Third Vaccination on Day 28). [ Time Frame: Day 63 +/- 2 days ]

Original Primary Outcome: Immunogenicity as measured by anti-protective antigen (PA) antibody responses using the toxin neutralization antibody assay [ Time Frame: 100 days ]

Current Secondary Outcome:

• Percentage of Subjects Achieving a TNA Response of a Predefined Threshold Value at Day 70. [ Time Frame: Day 70 +/- 2 days ]
  Neutralizing antibody levels in blinded serum samples were measured using a validated anthrax lethal toxin neutralization assay. The primary assay endpoint was the 50% neutralization factor (TNA NF50), which is calculated as the ratio of the 50% effective dose (ED50) of the test sample to the ED50 of a reference serum.
• Average Percentage of Subjects Achieving a TNA Response of a Predefined Threshold Value Between Days 63 and 100 (Inclusive). [ Time Frame: Days 63 to 100 ]
  Neutralizing antibody levels in blinded serum samples were measured using a validated anthrax lethal toxin neutralization assay. The primary assay endpoint was the 50% neutralization factor (TNA NF50), which is calculated as the ratio of the 50% effective dose (ED50) of the test sample to the ED50 of a reference serum.
• Incidence of Injection Site Reactions by Severity (Mild, Moderate, Severe) From Subject Diary Cards [ Time Frame: Web-enabled diaries were completed for 7 days after each of three injections (Days 0, 14, and 28). ]
  Injection site reactions (warmth, tenderness, itching, pain, arm motion limitation, redness, lump, swelling, and bruise) were evaluated by using a web-enabled subject diary. Subjects assessed the severity of warmth, tenderness, itching, pain, arm motion limitation, lump, and bruise as absent, mild, moderate, or severe based on the degree of interference with daily activities. Severity of redness and swelling were based on the diameter of the affected area. Severe injection site reactions were recorded as adverse events by the investigator site staff after confirmation with the subject.
• Percentage of Injection Site Reactions by Severity (Mild, Moderate, Severe) From Subject Diary Cards [ Time Frame: Web-enabled diaries were completed for 7 days after each of three injections (Days 0, 14, and 28). ]
  Injection site reactions (warmth, tenderness, itching, pain, arm motion limitation, redness, lump, swelling, and bruise) were evaluated by using a web-enabled subject diary. Subjects assessed the severity of warmth, tenderness, itching, pain, arm motion limitation, lump, and bruise as absent, mild, moderate, or severe based on the degree of interference with daily activities. Severity of redness and swelling were based on the diameter of the affected area. Severe injection site reactions were recorded as adverse events by the investigator site staff after confirmation with the subject.
• Incidence of Systemic Reactions by Severity (Mild, Moderate, Severe) From Subject Diary Cards [ Time Frame: Web-enabled diaries were completed for 7 days after each of three injections (Days 0, 14, and 28). ]
  Systemic reactions (fatigue/ tiredness, muscle ache, headache, and fever) were evaluated by using a web-enabled subject diary. Subjects assessed severity as absent, mild, moderate, or severe based on the degree of interference with daily activities. Severity of fever was assessed using a grading scale. Severe systemic reactions were to be recorded as adverse events by the investigator site staff after confirmation with the subject.
• Percentage of Systemic Reactions by Severity (Mild, Moderate, Severe) From Subject Diary Cards [ Time Frame: Web-enabled diaries were completed for 7 days after each of three injections (Days 0, 14, and 28). ]
  Systemic reactions (fatigue/ tiredness, muscle ache, headache, and fever) were evaluated by using a web-enabled subject diary. Subjects assessed severity as absent, mild, moderate, or severe based on the degree of interference with daily activities. Severity of fever was assessed using a grading scale. Severe systemic reactions were to be recorded as adverse events by the investigator site staff after confirmation with the subject.

Original Secondary Outcome: Immunogenicity, as defined by a predicted vaccine efficacy at defined timepoints. [ Time Frame: 100 days ]

Information By: Emergent BioSolutions

Dates:
Date Received: December 12, 2011
Date Started: November 2011
Date Completion:
Last Updated: September 25, 2013
Last Verified: September 2013