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

• Sponsor: Albert B. Sabin Vaccine Institute (Other)
• Overall Status: Completed
• CT.gov ID: NCT00603889
• Collaborator: (none)
• Enrollment: 12
• Location: 1
• Arm: 1
• Duration (Months): 2
• Patients Per Site Per Month: 6

Study Details

Study Description

Brief Summary

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 or Disease	Intervention/Treatment	Phase
Hookworm Infection; Allergy	Biological: Na-ASP-2 Skin Test Reagent	N/A

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.

Study Design

• Study Type: Interventional
• Actual Enrollment: 12 participants
• Allocation: N/A
• Intervention Model: Single Group Assignment
• Masking: None (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
• Study Start Date: Mar 1, 2008
• Actual Primary Completion Date: May 1, 2008
• Actual Study Completion Date: May 1, 2008

Arms and Interventions

Arm	Intervention/Treatment
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

Outcome Measures

Primary Outcome Measures

1. 100 Mcg/ml Na-ASP-2 Prick-puncture Skin Test [15 minutes after skin test application]

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

Secondary Outcome Measures

1. 1000 Mcg/ml Na-ASP-2 Prick-puncture Skin Test [15 minutes after skin test application]

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

2. 100 Mcg/ml Na-ASP-2 Intradermal Skin Test [15 minutes after skin test application]

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

3. 1000 Mcg/ml Na-ASP-2 Intradermal Skin Test [15 minutes after skin test application]

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

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years to 45 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

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

Locations

	Site	City	State	Country	Postal Code
1	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

Study Documents (Full-Text)

None provided.

More Information

Publications

• Diemert DJ, Bethony JM, Hotez PJ. Hookworm vaccines. Clin Infect Dis. 2008 Jan 15;46(2):282-8. doi: 10.1086/524070. Review.
• Fujiwara RT, Bethony J, Bueno LL, Wang Y, Ahn SY, Samuel A, Bottazzi ME, Hotez P, Mendez S. Immunogenicity of the hookworm Na-ASP-2 vaccine candidate: characterization of humoral and cellular responses after vaccination in the Sprague Dawley rat. Hum Vaccin. 2005 May-Jun;1(3):123-8. Epub 2005 May 20.
• Goud GN, Bottazzi ME, Zhan B, Mendez S, Deumic V, Plieskatt J, Liu S, Wang Y, Bueno L, Fujiwara R, Samuel A, Ahn SY, Solanki M, Asojo OA, Wang J, Bethony JM, Loukas A, Roy M, Hotez PJ. Expression of the Necator americanus hookworm larval antigen Na-ASP-2 in Pichia pastoris and purification of the recombinant protein for use in human clinical trials. Vaccine. 2005 Sep 15;23(39):4754-64.

• Responsible Party: Albert B. Sabin Vaccine Institute
• ClinicalTrials.gov Identifier: NCT00603889
• Other Study ID Numbers: SVI-07-02
• First Posted: Jan 29, 2008
• Last Update Posted: Feb 23, 2012
• Last Verified: Jan 1, 2012

• Keywords provided by Albert B. Sabin Vaccine Institute: Hookworm; Allergy; Vaccine; Skin test
• Additional relevant MeSH terms: Hookworm Infections; Ancylostomiasis

Study Results

Participant Flow

Recruitment Details	Recruitment occurred between March and May 2008, primarily by means of advertising the study in and around The George Washington University, where the study site is located.

Arm/Group Title	Na-ASP-2 Hookworm Antigen Skin Test
Arm/Group Description	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.
Period Title: Overall Study
STARTED	12
COMPLETED	12
NOT COMPLETED	0

Baseline Characteristics

Arm/Group Title	Na-ASP-2 Hookworm Antigen Skin Test
Arm/Group Description	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.
Overall Participants	12
Age (Count of Participants)
<=18 years	0 0%
Between 18 and 65 years	12 100%
>=65 years	0 0%
Sex: Female, Male (Count of Participants)
Female	8 66.7%
Male	4 33.3%
Region of Enrollment (participants) [Number]
United States	12 100%

Outcome Measures

1. Primary Outcome

Title	100 Mcg/ml Na-ASP-2 Prick-puncture Skin Test
Description	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 < ½ histamine diameter ≥ ½ histamine; < histamine diameter = size of histamine control ± 1 mm > histamine diameter; < 2x diameter ≥ 2x histamine control
Time Frame	15 minutes after skin test application

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Na-ASP-2 Hookworm Antigen Skin Test
Arm/Group Description	Application of different concentrations of the Na-ASP-2 antigen skin test reagent as prick-puncture ("scratch test") and intradermal injections, applied to participants' forearms.
Measure Participants	12
Mean (Full Range) [Units on a scale]	0

2. Secondary Outcome

Title	1000 Mcg/ml Na-ASP-2 Prick-puncture Skin Test
Description	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 < ½ histamine diameter ≥ ½ histamine; < histamine diameter = size of histamine control ± 1 mm > histamine diameter; < 2x diameter ≥ 2x histamine control
Time Frame	15 minutes after skin test application

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Na-ASP-2 Hookworm Antigen Skin Test
Arm/Group Description	Application of different concentrations of the Na-ASP-2 antigen skin test reagent as prick-puncture ("scratch test") and intradermal injections, applied to participants' forearms.
Measure Participants	12
Mean (Full Range) [units on a scale]	0.21

3. Secondary Outcome

Title	100 Mcg/ml Na-ASP-2 Intradermal Skin Test
Description	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 < ½ histamine diameter ≥ ½ histamine; < histamine diameter = size of histamine control ± 1 mm > histamine diameter; < 2x diameter ≥ 2x histamine control
Time Frame	15 minutes after skin test application

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Na-ASP-2 Hookworm Antigen Skin Test
Arm/Group Description	Application of different concentrations of the Na-ASP-2 antigen skin test reagent as prick-puncture ("scratch test") and intradermal injections, applied to participants' forearms.
Measure Participants	12
Mean (Full Range) [units on a scale]	0.17

4. Secondary Outcome

Title	1000 Mcg/ml Na-ASP-2 Intradermal Skin Test
Description	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 < ½ histamine diameter ≥ ½ histamine; < histamine diameter = size of histamine control ± 1 mm > histamine diameter; < 2x diameter ≥ 2x histamine control
Time Frame	15 minutes after skin test application

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Na-ASP-2 Hookworm Antigen Skin Test
Arm/Group Description	Application of different concentrations of the Na-ASP-2 antigen skin test reagent as prick-puncture ("scratch test") and intradermal injections, applied to participants' forearms.
Measure Participants	12
Mean (Full Range) [units on a scale]	1.25

Adverse Events

Arm/Group Title	Na-ASP-2 Hookworm Antigen Skin Test
Arm/Group Description	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.
All Cause Mortality
	Na-ASP-2 Hookworm Antigen Skin Test
	Affected / at Risk (%)	# Events
Total	/ (NaN)
Serious Adverse Events
	Na-ASP-2 Hookworm Antigen Skin Test
	Affected / at Risk (%)	# Events
Total	0/12 (0%)
Other (Not Including Serious) Adverse Events
	Na-ASP-2 Hookworm Antigen Skin Test
	Affected / at Risk (%)	# Events
Total	2/12 (16.7%)
Skin and subcutaneous tissue disorders
Delayed Skin Test Reaction	2/12 (16.7%)	2

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.