A Phase 1 interventional study of Necator americanus Hookworm Larvae in Hookworm Infection, sponsored by Baylor College of Medicine. Recruiting at 1 site in United States. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-18.
Sponsored by Baylor College of Medicine · Phase 1, Interventional, and Other
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.
Open-label, dose-escalation clinical study in healthy, hookworm-naïve adults:
In Cohort 1, ten (10) volunteers will receive an inoculum of 25 infectious Necator americanus larvae. In Cohort 2, ten (10) volunteers will receive an inoculum of 50 infectious Necator americanus larvae. In the optional Cohort 3, fifteen (15) volunteers will receive an inoculum of 75 infectious Necator americanus larvae.
The cohorts will be enrolled in a staggered fashion with safety data assessed prior to larval dose escalation. Cohort 2 will be inoculated no earlier than 8 weeks after the last volunteer is inoculated in Cohort 1. The optional Cohort 3 will be inoculated no sooner than 8 weeks after the last volunteer is inoculated in Cohort 2. Cohort 3 will be enrolled only if the tolerability of the experimental infection of Cohort 2 is acceptable and does not result in significant adverse events.
Within each cohort, after Study Day 70, but before Study Day 77, up to 5 volunteers will undergo capsule endoscopy in order to visualize and count adult N. americanus hookworms residing in the intestine. Informed consent for capsule endoscopy will be obtained separately from the primary study, and agreement or refusal will not impact on a subject's eligibility to enroll or continue participation in the primary study.
Three months after larval administration, or at the time of study withdrawal, all participants will receive a 3-dose treatment of albendazole (400 mg per dose) for clearance of experimental infection.
Exclusion Criteria:
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
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
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
Infectious larvae of the human hookworm Necator americanus
Also known as: Na-L3
Study product-related adverse events
Frequency of study product-related adverse events, graded by severity, for different doses of N. americanus Larval Inoculum.
Time frame: Up to 6 months after dosing
Fecal egg counts
To determine the dose of N. americanus Larval Inoculum that generates the highest fecal egg counts, measured by fecal microscopy.
Time frame: Up to Study Day 101
Number of adult hookworms in feces post-treatment
To compare the N. americanus Larval Inoculum dose received with the number of adult worms present in the gut, as determined by capsule endoscopy.
Time frame: Study Days 87-101
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Baylor College of Medicine