Infection of healthy adults with hookworm larvae to test a vaccine

An Experimental Infection Study of Dermally-applied Infectious Necator Americanus Hookworm Larvae in Hookworm-naïve Adults

This study is testing a new hookworm vaccine in healthy adults to see if it can protect them from getting infected after being exposed to hookworm larvae.

Quick facts

• Phase: Phase 1
• Study type: Interventional
• Enrollment: 35 (estimated)
• Ages: 18 Years to 45 Years
• Sex: All
• Sponsor: Baylor College of Medicine (Academic / other)
• Locations: 1 site (Washington D.C., District of Columbia)
• Trial ID: NCT01940757 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to develop an experimental hookworm infection model to evaluate the feasibility and efficacy of a candidate hookworm vaccine targeting the blood-feeding pathway of adult hookworms. Healthy, hookworm-naïve adults will be vaccinated and subsequently challenged with different doses of Necator americanus larvae to assess the vaccine's impact on infection. The study will be conducted in cohorts, with safety data evaluated before escalating the larval doses. Participants will undergo capsule endoscopy to visualize and count adult hookworms in the intestine after the larval administration.

Who should consider this trial

Good fit: Ideal candidates for this study are healthy males and females aged 18 to 45 who have never been infected with hookworms.

Not a fit: Patients with significant underlying health conditions or those who are pregnant or breastfeeding will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to the development of an effective vaccine against hookworm infections.

How similar studies have performed: While this approach is novel, similar studies have shown promise in developing vaccines for parasitic infections.

Eligibility criteria

Inclusion Criteria:

* Males or females between 18 and 45 years, inclusive.
* Good general health as determined by means of the screening procedure.
* Available for the duration of the trial (6 months).
* Willingness to participate in the study as evidenced by signing the informed consent document.

Exclusion Criteria:

* Pregnancy as determined by a positive urine human choriogonadotropin (hCG) (if female).
* Participant unwilling to use reliable contraception methods while participating in the study (if female and not surgically sterile, abstinent or at least 2 years post-menopausal).
* Currently lactating and breast-feeding (if female).
* Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, diabetes, or renal disease by history, physical examination, and/or laboratory studies.
* Known or suspected immunodeficiency.
* Laboratory evidence of liver disease (alanine aminotransferase \[ALT\] greater than 1.25-times the upper reference limit).
* Laboratory evidence of renal disease (serum creatinine greater than 1.25-times the upper reference limit, or more than trace protein or blood on urine dipstick testing).
* Laboratory evidence of hematologic disease (hemoglobin \<11.5 g/dl \[females\] or \<12.5 g/dl \[males\]; absolute leukocyte count \<3.6 or \>10.7 x 103/mm3; absolute neutrophil count \[ANC\] \<1.7 x 103/mm3; absolute lymphocyte count \<0.7 x 103/mm3; or platelet count \<140 x 103/mm3).
* History of iron deficiency anemia.
* History of hypoalbuminemia.
* Laboratory evidence of a coagulopathy (PTT or PT INR greater than 1.1-times the upper reference limit).
* Serum glucose (random) greater than 1.2-times the upper reference limit.
* 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.
* 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.
* Severe asthma as defined by the need for daily use of inhalers or emergency clinic visit or hospitalization within 6 months of the volunteer's expected Day 0 of the study.
* Positive ELISA for hepatitis B surface antigen (HBsAg).
* Positive confirmatory test for HIV infection.
* Positive confirmatory test for hepatitis C virus (HCV) infection.
* Use of corticosteroids (excluding topical or nasal) or immunosuppressive drugs within 30 days of the volunteer's expected Day 0 of this study or planned use during the study.
* Receipt of a live vaccine within 4 weeks or a killed vaccine within 2 weeks prior to the volunteer's expected Day 0 of the study.
* Receipt of blood products within the past 6 months.
* Known allergy to amphotericin B or gentamicin.
* History of previous infection with hookworm or residence for more than 6 months in a hookworm-endemic area.

Where this trial is running

Washington D.C., District of Columbia

• George Washington University Medical Faculty Associates — Washington D.C., District of Columbia, United States (Recruiting)

Study contacts

• Principal investigator: David J Diemert, MD — George Washington University
• Study coordinator: Study Coordinator

Conditions Hookworm Infection; Necator americanus; Experimental challenge infection