Development of a Skin Test for the Na-ASP-2 Hookworm Antigen

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Albert B. Sabin Vaccine Institute
ClinicalTrials.gov Identifier:
NCT00603889
First received: January 17, 2008
Last updated: January 18, 2012
Last verified: January 2012
  Purpose

Na-ASP-2 is a protein expressed during the larval stage of the N. americanus hookworm life cycle. In a clinical study in previously hookworm-infected adults in Brazil, this protein induced urticarial reactions (rash) in a subset of volunteers. This study will evaluate solutions of varying concentrations of the protein in both a skin prick-puncture and intradermal test that will eventually be used to screen volunteers living in hookworm endemic areas who are being considered as potential participants in vaccine trials, to reduce the potential of inducing allergic reactions in those vaccinated with the Na-ASP-2 Hookworm Vaccine.


Condition Intervention
Hookworm Infection
Allergy
Biological: Na-ASP-2 Skin Test Reagent

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic
Official Title: Development of a Skin Test to Detect Immediate-type Hypersensitivity to the Experimental Na-ASP-2 Hookworm Antigen

Resource links provided by NLM:


Further study details as provided by Albert B. Sabin Vaccine Institute:

Primary Outcome Measures:
  • 100 Mcg/ml Na-ASP-2 Prick-puncture Skin Test [ Time Frame: 15 minutes after skin test application ] [ Designated as safety issue: No ]

    Mean grade of wheal reaction after 2 applications of the skin test reagent per participant. For each skin test reaction, the grade of the test was determined based on the mean of the longest and orthogonal diameters, which was then compared to the equivalent measurements of a histamine solution positive control that was applied at the same time as the test. Grading was as follows:

    0 no discernible wheal

    1. < ½ histamine diameter
    2. ≥ ½ histamine; < histamine diameter
    3. = size of histamine control ± 1 mm
    4. > histamine diameter; < 2x diameter
    5. ≥ 2x histamine control


Secondary Outcome Measures:
  • 1000 Mcg/ml Na-ASP-2 Prick-puncture Skin Test [ Time Frame: 15 minutes after skin test application ] [ Designated as safety issue: No ]

    Mean grade of wheal reaction after 2 applications of the skin test reagent per participant. For each skin test reaction, the grade of the test was determined based on the mean of the longest and orthogonal diameters, which was then compared to the equivalent measurements of a histamine solution positive control that was applied at the same time as the test. Grading was as follows:

    0 no discernible wheal

    1. < ½ histamine diameter
    2. ≥ ½ histamine; < histamine diameter
    3. = size of histamine control ± 1 mm
    4. > histamine diameter; < 2x diameter
    5. ≥ 2x histamine control

  • 100 Mcg/ml Na-ASP-2 Intradermal Skin Test [ Time Frame: 15 minutes after skin test application ] [ Designated as safety issue: No ]

    Mean grade of wheal reaction after 2 applications of the skin test reagent per participant. For each skin test reaction, the grade of the test was determined based on the mean of the longest and orthogonal diameters, which was then compared to the equivalent measurements of a histamine solution positive control that was applied at the same time as the test. Grading was as follows:

    0 no discernible wheal

    1. < ½ histamine diameter
    2. ≥ ½ histamine; < histamine diameter
    3. = size of histamine control ± 1 mm
    4. > histamine diameter; < 2x diameter
    5. ≥ 2x histamine control

  • 1000 Mcg/ml Na-ASP-2 Intradermal Skin Test [ Time Frame: 15 minutes after skin test application ] [ Designated as safety issue: No ]

    Mean grade of wheal reaction after 2 applications of the skin test reagent per participant. For each skin test reaction, the grade of the test was determined based on the mean of the longest and orthogonal diameters, which was then compared to the equivalent measurements of a histamine solution positive control that was applied at the same time as the test. Grading was as follows:

    0 no discernible wheal

    1. < ½ histamine diameter
    2. ≥ ½ histamine; < histamine diameter
    3. = size of histamine control ± 1 mm
    4. > histamine diameter; < 2x diameter
    5. ≥ 2x histamine control


Enrollment: 12
Study Start Date: March 2008
Study Completion Date: May 2008
Primary Completion Date: May 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Na-ASP-2 Hookworm Antigen Skin Test
All participants will have the same number of concentrations of the Na-ASP-2 skin test reagent applied to their arms, using both the prick-puncture and intradermal techniques.
Biological: Na-ASP-2 Skin Test Reagent
Na-ASP-2 Hookworm Skin Test Reagent, 1-1000 mcg/mL solution

Detailed Description:
  • Study site: George Washington University Medical Center
  • Number of participants: up to 15
  • Study duration: up to 3 months; each participant will undergo a minimum of one screening visit and one study visit.
  • Each participant will have both skin prick-puncture and intradermal skin tests applied on the same study day. The prick-puncture and intradermal tests will be applied sequentially to the volar aspects of the participant's forearms:

    1. Skin prick-puncture: four different concentrations of Na-ASP-2 solution (1, 10, 100, and 1000 μg/mL) will be applied simultaneously in duplicate, to the left forearm.
    2. Intradermal: three different concentrations of Na-ASP-2 (10, 100, and 1000 μg/mL) will be injected simultaneously, in duplicate, to the right forearm.
    3. Allergen diluent and histamine solutions will be utilized as the negative and positive controls, respectively, for both the skin prick-puncture and intradermal tests.
    4. Participants will be observed in the study clinic for at least 30 minutes following application of the skin tests, and will be contacted via telephone 2 days following skin testing.
    5. Sizes of the wheal and erythema reactions for each application will be recorded and graded in comparison to the histamine positive control reaction.
  • Each participant will have blood collected via venipuncture (a maximum of 25 mL) immediately prior to application of the skin tests, in order to measure antibodies (particularly IgG and IgE) to Na-ASP-2 using an ELISA procedure.
  Eligibility

Ages Eligible for Study:   18 Years to 45 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Males or females between 18 and 45 years of age, inclusive.
  • Good general health as determined by means of the screening procedure.
  • Willingness to participate in the study as evidenced by signing the informed consent document.

Exclusion Criteria:

  • History of previous infection with hookworm.
  • Prior extensive and continuous travel, work, or residence (> 1 month) in a hookworm-endemic region.
  • Pregnancy as determined by a positive urine hCG test (if female).
  • Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, or renal disease by history or physical examination.
  • Behavioral, cognitive, or psychiatric disease that in the opinion of the investigator affects the ability of the volunteer to understand and cooperate with the study protocol.
  • Other condition that in the opinion of the investigator would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.
  • Participation in an investigational vaccine or drug trial within 14 days of starting this study.
  • Volunteer has had medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 12 months.
  • History of a severe allergic reaction or anaphylaxis.
  • Known immunodeficiency syndrome.
  • Use of corticosteroids (excluding topical or nasal) or immunosuppressive drugs within 30 days of starting this study.
  • History of a surgical splenectomy.
  • Extensive dermatitis precluding skin testing
  • Current use of a beta blocker (oral or topical) or anti-histamine medication. A volunteer may participate in the study if they agree to withhold use of an anti-histamine for at least 5 days prior to application of the skin test.
  • Use of a tricyclic anti-depressant within the past month.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00603889

Locations
United States, District of Columbia
GWUMC Clinical Trials Unit
Washington, District of Columbia, United States, 20037
Sponsors and Collaborators
Albert B. Sabin Vaccine Institute
Investigators
Principal Investigator: David Parenti, MD GWUMC Medical Faculty Associates
  More Information

Publications:
Responsible Party: Albert B. Sabin Vaccine Institute
ClinicalTrials.gov Identifier: NCT00603889     History of Changes
Other Study ID Numbers: SVI-07-02
Study First Received: January 17, 2008
Results First Received: June 21, 2011
Last Updated: January 18, 2012
Health Authority: United States: Food and Drug Administration

Keywords provided by Albert B. Sabin Vaccine Institute:
Hookworm
Allergy
Vaccine
Skin test

Additional relevant MeSH terms:
Ancylostomiasis
Hookworm Infections
Helminthiasis
Nematode Infections
Parasitic Diseases
Secernentea Infections
Strongylida Infections

ClinicalTrials.gov processed this record on October 23, 2014