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CompletedNCT00053482Updated Mar 18, 2024Results posted

Dose Study of ACAM2000 Smallpox Vaccine in Previously Vaccinated Adults

A Phase 2 interventional study of ACAM2000 Smallpox Vaccine and Vaccinia virus (calf lymph) smallpox vaccine: Dryvax® in Smallpox, sponsored by Emergent BioSolutions. Completed at 3 sites in United States. Open to participants aged 28 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2024-03-18.

Sponsored by Emergent BioSolutions · Phase 2, Interventional, and Prevention

Phase
Phase 2
Study type
Interventional
Enrollment
357
Allocation
Randomized
Ages
28 Years and older
Sex
All
01

Study 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.

Read the 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.
02

Conditions studied

  • Smallpox

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Keywords

  • Smallpox vaccines
  • Dryvax®
  • Orthopoxvirus
  • Vaccinia virus
  • ACAM2000
03

In context

Smallpox

73 studies on the registry are indexed under Smallpox; 5 are open to participants now.

This study's enrollment of 357 is above the median of 150 across 61 interventional studies indexed under Smallpox.

Browse Smallpox studies →

Lead sponsor

Emergent BioSolutions is the lead sponsor of 47 studies on the registry; 7 are open to participants now.

Of its 11 completed or terminated interventional studies of FDA-regulated products, 7 (64%) have results posted.

Browse Emergent BioSolutions studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
28 Years and older
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • have a history of previous smallpox vaccination greater than 10 years previous to the date of screening and presence of a vaccination scar.
  • females must not be pregnant, lactating and must agree to use an effective form of for the 30 days following vaccination or unable to bear children.
  • agree to be available for the entire study and agree to comply with all requirements.

Exclusion criteria

exclusion criteria:

  • children 1 year of age or younger in the household or be in close contact
  • smallpox vaccination within ten years
  • known or suspected Human immunodeficient virus () infection, primary immunodeficiency disorder, leukemia, lymphoma, or current radiation treatment or use of or anti-neoplastic drugs or have a household member or intimate contact with the conditions listed above.
  • renal disease
  • current or past history of eczema or a household member or direct contact who has eczema.
  • known allergy or past allergic reactions to latex gloves or to antibiotics which include neomycin, streptomycin, chlortetracycline, and polymyxin B
  • known allergy or past allergic reaction to blood products.
  • known allergy to cidofovir or sulfa-containing drugs.
  • history of allergic phenomena following smallpox vaccination in the past, including urticaria, erythema multiforme, or Stevens-Johnson syndrome.
  • transfusion of blood or treatment with any blood product.
  • current or history of drug or alcohol abuse
  • innoculation with any other or participating in another drug or vaccine trial within 30 days of enrollment.
Terms in these criteria, in plain language(4)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Live vaccines

Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.

05

Study design

Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
357 participants (actual)

Study arms

  • Experimental
    Group 1: ACAM2000

    Participants will receive dose 1 of the ACAM2000 smallpox vaccine

    Biological: ACAM2000 Smallpox Vaccine

  • Experimental
    Group 2: ACAM2000

    Participants will receive dose 2 of the ACAM2000 smallpox vaccine

    Biological: ACAM2000 Smallpox Vaccine

  • Experimental
    Group 3: ACAM2000

    Participants will receive dose 3 of the ACAM2000 smallpox vaccine

    Biological: ACAM2000 Smallpox Vaccine

  • Experimental
    Group 4: ACAM2000

    Participants will receive dose 4 of the ACAM2000 smallpox vaccine

    Biological: ACAM2000 Smallpox Vaccine

  • Active comparator
    Group 5: Dryvax®

    Participants will receive dose 1 of Dryvax® smallpox vaccine.

    Biological: Vaccinia virus (calf lymph) smallpox vaccine: Dryvax®

Interventions

  • BiologicalACAM2000 Smallpox Vaccine

    Group 1 dose: 1.0x10-8th PFU/ml, Group 2 dose: 2.0x10-7th PFU/ml, Group 3 dose: 1.0x10-7th PFU/ml, Group 4 dose: 5.0x10-6th PFUL/ml

  • BiologicalVaccinia virus (calf lymph) smallpox vaccine: Dryvax®

    Group 5 dose: 1.0x10-8th PFU/ml

    Also known as: Dryvax®

06

What researchers measure

Primary outcomes

  1. The Neutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

    The neutralizing antibody response titers were determined by the Plaque-Reduction Neutralization Test (PRNT50)

    Time frame: Day 30 post-vaccination

  2. Participants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.

    Time frame: Day 30 post-vaccination

  3. Number of Participants Reporting Adverse Events of Severe Intensity Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

    Time frame: Days 0 to 30 post-vaccination

Other outcomes

  1. Number of Participants With Treatment-Emergent Rash Events Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

    Time frame: Days 0 to 30 post-vaccination

  2. Selected Hematology Parameters (Hematocrit, Lymphocyte, and Eosinophil) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

    Time frame: Days 0 (Baseline) and 15 post-vaccination

  3. Selected Hematology Parameters (Red Bood Cell and Platelets) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

    Time frame: Days 0 (Baseline) and 15 post-vaccination

  4. Clinical Chemistry Parameters (Creatinine and Glucose) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

    Time frame: Days 0 (Baseline) and 15 post-vaccination

  5. Clinical Chemistry Parameters (Aspartate Transaminase and Alanine Transaminase) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

    Time frame: Days 0 (Baseline) and 15 post-vaccination

07

Results

Posted Feb 11, 2011

Participant flow

Participants were enrolled from 07 January 2003 to 31 March 2003 in 3 medical centers in the US.

Participant flow — Overall Study
MilestoneACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Started511021025052
Completed511021025052
Not completed00000

Outcome measures

PrimaryThe Neutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

The neutralizing antibody response titers were determined by the Plaque-Reduction Neutralization Test (PRNT50)

Time frame:
Day 30 post-vaccination
Reported as:
Mean · PRNT50 Titers
The Neutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
PRNT50 TitersACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Baseline77 ± 119.4112 ± 280.576 ± 108.791 ± 145.4186 ± 709.8
Day 15244 ± 485.4259 ± 449.1802 ± 4111.6546 ± 829.91287 ± 2198.4
PrimaryParticipants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
Time frame:
Day 30 post-vaccination
Reported as:
Number · Participants
Participants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
ParticipantsACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Participants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.1331413839
PrimaryNumber of Participants Reporting Adverse Events of Severe Intensity Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame:
Days 0 to 30 post-vaccination
Reported as:
Number · Participants
Number of Participants Reporting Adverse Events of Severe Intensity Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
ParticipantsACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Lymph Node Pain11110
Lymphadenopathy00100
Constipation00100
Toothache01000
Injection Site Erythema01343
Injection Site Pruritus01001
Injection Site Pain00001
Human Immunodeficiency Virus (HIV) Test Positive10000
Back Pain01000
Myalgia10000
Swelling Not Otherwise Specified00010
Migraine Not Otherwise Specified01000
Pregnancy Not Otherwise Specified01000
Calculus Renal Not Otherwise Specified01000
Other pre-specifiedNumber of Participants With Treatment-Emergent Rash Events Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame:
Days 0 to 30 post-vaccination
Reported as:
Number · Participants
Number of Participants With Treatment-Emergent Rash Events Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
ParticipantsACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Rash Not Otherwise Specified25553
Rash Macular00010
Rash Papular00100
Application Site Rash00112
Injection Site Rash10102
Any Rash35875
Other pre-specifiedSelected Hematology Parameters (Hematocrit, Lymphocyte, and Eosinophil) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame:
Days 0 (Baseline) and 15 post-vaccination
Reported as:
Mean · Percentage (%)
Selected Hematology Parameters (Hematocrit, Lymphocyte, and Eosinophil) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Percentage (%)ACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Hematocrit (Baseline)41.7 ± 3.5842.4 ± 3.8742.2 ± 3.6642.8 ± 3.6943.3 ± 3.62
Hematocrit (Day15)41.2 ± 3.5341.6 ± 3.8641.5 ± 3.6842.1 ± 3.3042.8 ± 3.27
Lymphocytes (Baseline)31.8 ± 7.2730.8 ± 6.6830.6 ± 7.8730.4 ± 6.9830.9 ± 6.27
Lymphocytes (Day15)32.4 ± 6.8830.8 ± 7.1931.3 ± 8.2631.2 ± 7.3633.4 ± 7.00
Eosinophils (Baseline)2.8 ± 1.892.5 ± 2.092.5 ± 1.502.3 ± 1.372.8 ± 1.84
Eosinophils (Day15)2.5 ± 1.432.5 ± 2.022.6 ± 1.662.5 ± 1.553.1 ± 2.2
Other pre-specifiedSelected Hematology Parameters (Red Bood Cell and Platelets) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame:
Days 0 (Baseline) and 15 post-vaccination
Reported as:
Mean · x10^6th/µL
Selected Hematology Parameters (Red Bood Cell and Platelets) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
x10^6th/µLACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Red Blood Cell count (Baseline)4.7 ± 0.354.8 ± 0.474.8 ± 0.464.9 ± 0.404.9 ± 0.45
Red Blood Cell count (Day15)4.7 ± 0.364.7 ± 0.504.7 ± 0.504.8 ± 0.364.8 ± 0.41
Platelets (Baseline)279 ± 69.7276 ± 54.5277 ± 71.5285 ± 58.4280 ± 75.7
Platelets (Day15)286 ± 66.7281 ± 61.3276 ± 67.2284 ± 63.2284 ± 77.0
Other pre-specifiedClinical Chemistry Parameters (Creatinine and Glucose) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame:
Days 0 (Baseline) and 15 post-vaccination
Reported as:
Mean · mg/dL
Clinical Chemistry Parameters (Creatinine and Glucose) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
mg/dLACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Creatinine (Baseline)0.90 ± 0.1220.94 ± 0.1670.92 ± 0.1870.94 ± 0.1840.97 ± 0.156
Creatinine (Day 15)0.91 ± 0.1450.96 ± 0.1810.95 ± 0.1840.96 ± 0.1840.98 ± 0.138
Glucose (Baseline)91 ± 11.787 ± 8.792 ± 15.392 ± 13.488 ± 10.7
Glucose (Day 15)94 ± 22.690 ± 18.990 ± 16.394 ± 28.495 ± 27.3
Other pre-specifiedClinical Chemistry Parameters (Aspartate Transaminase and Alanine Transaminase) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame:
Days 0 (Baseline) and 15 post-vaccination
Reported as:
Mean · IU/L
Clinical Chemistry Parameters (Aspartate Transaminase and Alanine Transaminase) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
IU/LACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Aspartate transaminase (Baseline)27 ± 13.224 ± 9.923 ± 10.322 ± 6.922 ± 6.2
Aspartate transaminase (Day 15)24 ± 11.523 ± 8.724 ± 10.721 ± 10.421 ± 5.8
Alanine transaminase (Baseline)39 ± 16.339 ± 19.537 ± 17.337 ± 15.736 ± 12.9
Alanine transaminase (Day 15)39 ± 20.138 ± 20.437 ± 19.237 ± 16.034 ± 13.8

Adverse events

Collected over Adverse events data were collected from the day of vaccination for up to 6 months post-vaccination.. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
ACAM2000 Dose 1—1/51 (2%)48/51 (94.1%)
ACAM2000 Dose 2—1/102 (1%)93/102 (91.2%)
ACAM2000 Dose 3—0/102 (0%)98/102 (96.1%)
ACAM2000 Dose 4—0/50 (0%)49/50 (98%)
Dryvax® Vaccine—0/52 (0%)51/52 (98.1%)
Most frequent serious events
Most frequent serious events
EventACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
HIV test positiveInvestigations1/510/1020/1020/500/52
Pregnancy Not Otherwise SpecifiedPregnancy, puerperium and perinatal conditions0/511/1020/1020/500/52
Most frequent other events
Showing 10 of 19
Most frequent other events
EventACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® Vaccine
Injection Site PruritusGeneral disorders29/5159/10277/10238/5043/52
Injection Site ErythemaGeneral disorders20/5142/10248/10224/5030/52
Headache Not Otherwise SpecifiedNervous system disorders24/5139/10246/10225/5021/52
FatigueGeneral disorders15/5128/10241/10218/5018/52
Injection Site PainGeneral disorders13/5127/10236/10216/5019/52
MalaiseGeneral disorders17/5120/10229/10218/5015/52
MyalgiaMusculoskeletal and connective tissue disorders14/5133/10230/10215/507/52
Lymph Node PainBlood and lymphatic system disorders5/518/10220/10214/5012/52
Feeling HotGeneral disorders12/5115/10214/10213/506/52
Diarrhea Not Otherwise SpecifiedGastrointestinal disorders8/5117/10211/10212/509/52

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)ACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® VaccineTotal
<=18 years000000
Between 18 and 65 years511021025052357
>=65 years000000
Age, Continuous
Age, Continuous(Years)ACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® VaccineTotal
Mean48 ± 9.748 ± 10.150 ± 11.747 ± 9.148 ± 9.248 ± 10.5
Sex: Female, Male
Sex: Female, Male(Participants)ACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® VaccineTotal
Female2757541819175
Male2445483233182
Region of Enrollment
Region of Enrollment(participants)ACAM2000 Dose 1ACAM2000 Dose 2ACAM2000 Dose 3ACAM2000 Dose 4Dryvax® VaccineTotal
United States511021025052357
08

Study locations

3 sites
  • PRA International
    Lenexa, Kansas 66219, United States
  • Bio-Kinetic Clinical Applications
    Springfield, Missouri 65802, United States
  • Memorial Hospital of Rhode Island Division of Infectious Diseases
    Pawtucket, Rhode Island 02860, United States
09

Timeline

Tracking since Sep 25, 2026
Not marked actual or estimatedDates not marked actual or estimated

The record gives a start of Jan 2003, a primary completion of Apr 2003 and a completion of Oct 2003. It does not say whether these dates are actual or estimated.

Results were first posted in Feb 2011, 7 years 10 months after primary completion.

How these figures are worked out, and which studies are left out of them.

Registered
Jan 30, 2003
First posted
Jan 31, 2003
Start
Jan 2003
Primary completionActual
Apr 2003
CompletionActual
Oct 2003
Results first posted
Feb 11, 2011
Last update
Mar 18, 2024
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Mar 18, 2024, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT00053482
Lead sponsor
Emergent BioSolutions
Responsible party
Sponsor
First posted
Jan 31, 2003
Start date
Jan 2003
Primary completion
Apr 2003
Completion
Oct 2003
Results posted
Feb 11, 2011
Last update
Mar 18, 2024

Study contacts

Medical Director
study director · Emergent BioSolutions

Oversight

Data monitoring committee
Yes
View the source record on ClinicalTrials.gov ↗

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