Experimental Infection of Hookworm-naïve Adults With Dermally-applied Infectious Necator Americanus Hookworm Larvae

NCT01940757 | Recruiting Phase 1 DMC

• 1 other identifier: SVI-CH-01
• Study Type: interventional
• Target: 35
• Locations: 1 country
• Sites: 1

Brief Summary

An experimental hookworm infection model is being developed to provide early proof-of-concept that a hookworm vaccine targeting the blood-feeding pathway of adult hookworms is feasible and efficacious. The proposed model consists of vaccinating healthy, hookworm-naïve adults with a candidate hookworm vaccine, followed by challenging them with the investigational product, Necator americanus Larval Inoculum to assess the effect of vaccination on infection. The first proposed study will be a feasibility study that will consist of administering different doses of the Necator americanus Larval Inoculum to healthy adult volunteers to determine the optimal dose (i.e., number of infectious larvae) that is safe, well-tolerated and results in consistent infection.

Conditions

Hookworm Infection

Keywords

Necator americanus; Hookworm Infection; Experimental challenge infection

Outcome Measures

Primary Outcomes (1)

• Study product-related adverse events

  Frequency of study product-related adverse events, graded by severity, for different doses of N. americanus Larval Inoculum.

  Up to 6 months after dosing

Secondary Outcomes (2)

• Fecal egg counts

  Up to Study Day 101

• Number of adult hookworms in feces post-treatment

  Study Days 87-101

Study Arms (3)

Cohort 1 (25 Necator americanus Hookworm Larvae)

EXPERIMENTAL

A dose of 25 Necator americanus Hookworm Larvae, administered via a sterile absorbent pad fixed with a transparent adhesive dressing for at least 1 hour.

Biological: Necator americanus Hookworm Larvae

Cohort 2 (50 Necator americanus Hookworm Larvae)

EXPERIMENTAL

A dose of 50 Necator americanus Hookworm Larvae, administered via a sterile absorbent pad fixed with a transparent adhesive dressing for at least 1 hour.

Biological: Necator americanus Hookworm Larvae

Cohort 3 (75 Necator americanus Hookworm Larvae)

EXPERIMENTAL

A dose of 75 Necator americanus Hookworm Larvae, administered via a sterile absorbent pad fixed with a transparent adhesive dressing for at least 1 hour.

Biological: Necator americanus Hookworm Larvae

Interventions

Necator americanus Hookworm Larvae BIOLOGICAL

Infectious larvae of the human hookworm Necator americanus

Also known as: Na-L3

Cohort 1 (25 Necator americanus Hookworm Larvae); Cohort 2 (50 Necator americanus Hookworm Larvae); Cohort 3 (75 Necator americanus Hookworm Larvae)

Eligibility Criteria

• Age: 18 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Baylor College of Medicine: lead

Study Sites (1)

George Washington University Medical Faculty Associates

Washington D.C., District of Columbia, 20037, United States

RECRUITING

Related Publications (1)

• Diemert D, Campbell D, Brelsford J, Leasure C, Li G, Peng J, Zumer M, Younes N, Bottazzi ME, Mejia R, Pritchard DI, Hawdon JM, Bethony JM. Controlled Human Hookworm Infection: Accelerating Human Hookworm Vaccine Development. Open Forum Infect Dis. 2018 Apr 19;5(5):ofy083. doi: 10.1093/ofid/ofy083. eCollection 2018 May.

  PMID: 29780848 DERIVED

MeSH Terms

Conditions

Hookworm Infections

Condition Hierarchy (Ancestors)

Strongylida Infections; Secernentea Infections; Nematode Infections; Helminthiasis; Parasitic Diseases; Infections

Study Officials

• David J Diemert, MD

  George Washington University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Study Coordinator

CONTACT

(202) 994-1599; gwvru@gwu.edu

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Sponsor

Study Record Dates

• First Submitted: September 9, 2013
• First Posted: September 12, 2013
• Study Start: January 1, 2015
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: November 4, 2025

Record last verified: 2025-11

Locations

US (1)