Dose Study of ACAM2000 Smallpox Vaccine in Previously Vaccinated Adults

Phase 2

Completed

• Conditions: Smallpox
• Interventions: Biological: ACAM2000 Smallpox Vaccine

• Registration Number: NCT00053482
• Lead Sponsor: Emergent BioSolutions

Brief Summary

The objective of this study is to determine the minimum dose of ACAM2000 needed to produce a cutaneous reaction in at least 90% of a population of healthy adults at least 28 years of age and previously vaccinated against smallpox.

Detailed Description

Specifically, the objectives of this study are to:

1. Compare the safety and tolerability of four dose levels of ACAM2000 and a standard dose of Dryvax® in healthy adults at least 28 years of age and previously vaccinated to smallpox. Safety and tolerability will be determined by examination of the local cutaneous reaction, adverse events, physical examinations, vital signs, structured interviews, and laboratory analysis.

2. Determine the immunogenicity of four dose levels of ACAM2000 and a standard dose of Dryvax® in healthy adults at least 28 years of age by comparing:

1. the proportion of subjects at each dose level who develop a major cutaneous reaction

2. the proportion of subjects in each treatment group who develop neutralizing antibodies, including the fold-increase in antibody titer between Baseline and Day 30 sera; and the geometric mean vaccinia neutralizing antibody titer on Day 30.

3. Determine the minimum dose of ACAM2000 that is calculated to produce a major cutaneous reaction in at least 90% of a population of healthy adults at least 28 years of age, with a history of smallpox vaccination.

Study Timeline

• Study Start: 2003-01
• Study First Submitted: 2003-01-30
• Study First Submitted QC: 2003-01-30
• Study First Posted: 2003-01-31
• Primary Completion: 2003-04
• Study Completion: 2003-10
• Results First Submitted: 2011-01-03
• Results First Submitted QC: 2011-01-14
• Results First Posted: 2011-02-11
• Status Verified: 2024-03
• Last Update Submitted: 2024-03-14
• Last Update Posted: 2024-03-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 357

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Group 1: ACAM2000	ACAM2000 Smallpox Vaccine	Participants will receive dose 1 of the ACAM2000 smallpox vaccine
Group 4: ACAM2000	ACAM2000 Smallpox Vaccine	Participants will receive dose 4 of the ACAM2000 smallpox vaccine
Group 3: ACAM2000	ACAM2000 Smallpox Vaccine	Participants will receive dose 3 of the ACAM2000 smallpox vaccine
Group 2: ACAM2000	ACAM2000 Smallpox Vaccine	Participants will receive dose 2 of the ACAM2000 smallpox vaccine

Primary Outcome Measures

Name	Time	Method
The Neutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine	Day 30 post-vaccination	The neutralizing antibody response titers were determined by the Plaque-Reduction Neutralization Test (PRNT50)
Participants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.	Day 30 post-vaccination
Number of Participants Reporting Adverse Events of Severe Intensity Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine	Days 0 to 30 post-vaccination

Trial Locations

Locations (3)

Bio-Kinetic Clinical Applications; 🇺🇸 Springfield, Missouri, United States

PRA International; 🇺🇸 Lenexa, Kansas, United States

Memorial Hospital of Rhode Island Division of Infectious Diseases; 🇺🇸 Pawtucket, Rhode Island, United States