Hookworm InfectionsPhase 2NCT03172975
Efficacy of Na-GST-1/Alhydrogel Hookworm Vaccine Assessed by Controlled Challenge Infection
A Phase 2 study testing Na-GST-1/Alhydrogel, Na-GST-1/Alhydrogel + CPG 10104 and Na-GST-1/Alhydrogel + GLA-AF in people with Hookworm Infections, run by Baylor College of Medicine at 1 site in United States.
Trial summary
This study evaluates the efficacy, safety and immunogenicity of different formulations of the Na-GST-1 hookworm vaccine using a controlled human hookworm infection model in healthy, hookworm-naive adults. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Hookworm Infections
- What is being tested?
- Na-GST-1/Alhydrogel, Na-GST-1/Alhydrogel + CPG 10104 and Na-GST-1/Alhydrogel + GLA-AF
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 39 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Mar 2018to 30 Jan 2025
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Males and non-pregnant females between 18 and 45 years, inclusive.
- Good general health as determined by means of the screening procedures1.
- Available for the duration of individual subject study participation (14 months).
- Willingness to participate in the study as evidenced by signing the informed consent document.
- Able to understand and comply with planned study procedures.
Who cannot join
- Pregnancy as determined by a positive urine human choriogonadotropin (hCG) test (if female).
- Subject unwilling to use effective contraception for a minimum of 30 days prior to vaccination and up until documentation of clearance of hookworm infection post-CHHI (if female and not surgically sterile, abstinent from intercourse with a male partner, in a monogamous relationship with a vasectomized partner, at least 2 years post-menopausal, or determined otherwise by medical evaluation to be sterile).
- Currently lactating and breast-feeding or plans to breastfeed at any given time from the first study vaccination until clearance of hookworm infection post-CHHI (if female).
- Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, gastrointestinal, diabetes, or renal disease by history, physical examination, and/or laboratory studies.
- Has a diagnosis of schizophrenia, bipolar disease or other major psychiatric condition that would make compliance with study visits/procedures difficult (e.g., subject with psychoses or history of suicide attempt or gesture in the 3 years before study entry, ongoing risk for suicide).
- Known or suspected immunodeficiency or immunosuppression as a result of an underlying illness or treatment (causes for immunosuppression may include, but are not limited to, poorly-controlled diabetes mellitus, chronic liver disease, renal insufficiency, active neoplastic disease or a history of hematologic malignancy, connective tissue disease, organ transplant).
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- 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 urine dipstick testing positive for glucose or more than trace protein).
- Laboratory evidence of hematologic disease (hemoglobin <11.1 g/dl [females] or <12.5 g/dl [males]; absolute leukocyte count <3400/mm3 or >10.8 x 103/mm3; absolute eosinophil count <500/mm3; or platelet count <140,000/mm3).
- 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.
- Planned participation in another investigational vaccine or drug trial within 30 days of starting this study or until the last study visit (this may include other licensed or unlicensed vaccines, drugs, biologics, devices, blood products, or medications).
- Volunteer has had medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 24 months.
- Positive fecal occult blood test at screening.
- Infection with a pathogenic intestinal helminth as determined by stool examination for ova and parasites at screening.
- History of iron deficiency anemia or laboratory evidence of iron deficiency (serum ferritin concentration below the lower reference limit).
- History of hypoalbuminemia.
- 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 first vaccination in the study.
- Positive test for hepatitis B surface antigen (HBsAg).
- Positive confirmatory test for HIV infection.
- Positive confirmatory test for hepatitis C virus (HCV) infection.
- Using or intends to continue using oral or parenteral corticosteroids, high-dose inhaled corticosteroids (>800 μg/day of beclomethasone dipropionate or equivalent) or other immunosuppressive or cytotoxic drugs within 30 days of the volunteer's expected first vaccination in 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 first vaccination in the study.
- Receipt of immunoglobin or other blood products (with exception of Rho D immunoglobulin) within 90 days of the planned first study vaccination.
- Known allergy to albendazole, amphotericin B or gentamicin.
- History of previous infection with hookworm or continuous residence for more than 6 months in a community where hookworm is endemic.
- Current or past scars, tattoos, or other disruptions of skin integrity at the intended site of larval application.
- Previous receipt of the Na-GST-1/Alhydrogel® hookworm vaccine.
- History of a surgical splenectomy.
- Pre-existing autoimmune or antibody-mediated diseases including but not limited to: systemic lupus erythematosis, rheumatoid arthritis, multiple sclerosis, Sjogren's syndrome, autoimmune thrombocytopenia; or laboratory evidence of possible autoimmune disease determined by a positive anti-dsDNA titer, positive rheumatoid factor, and/or proteinuria (greater than trace protein on urine dipstick testing).
Trial locations and contacts
1 site in 1 country.
United States1 site
George Washington University
Washington D.C., District of Columbia, 20037
About this study
Official title: Phase 2 Study to Assess the Safety, Efficacy and Immunogenicity of Na-GST-1/Alhydrogel Co-administered With Different Toll-Like Receptor Agonists in Hookworm- Naïve Adults
This study evaluates the efficacy, safety and immunogenicity of different formulations of the Na-GST-1 hookworm vaccine using a controlled human hookworm infection model in healthy, hookworm-naive adults.
Read the detailed description
Double blind, randomized, controlled, Phase 2 clinical trial in hookworm-unexposed adults living in the metropolitan area of Washington, DC. Subjects will receive three doses of the assigned vaccine formulation, or saline placebo, delivered intramuscularly on approximately Days 0, 56, and 112.
Subjects will be challenged with 50 infectious N. americanus larvae 4 weeks after 3rd vaccination. Fecal samples will be collected weekly starting 4 weeks post-challenge. Albendazole will be administered 20 weeks post-challenge to cure infections. Subjects will be followed until 10 months after their final vaccination.
Safety of vaccination will be measured from the time of each study vaccination (Day 0) through 14 days after each study vaccination by the occurrence of solicited injection site and systemic reactogenicity events. Safety of CHHI will be measure from the time of larval application (Day 140) through the first day of treatment with albendazole (Day 280).
Unsolicited non-serious adverse events (AEs) will be collected until approximately 1 month following each study vaccination and from study Day 140 (day of CHHI) through Day 280.
New-onset chronic medical conditions and Serious Adverse Events (SAEs) will be collected from the time of the first study vaccination through approximately 10 months after the third study vaccination (final visit). Clinical laboratory evaluations for safety will be performed on venous blood collected approximately 14 days after each vaccination and CHHI.
Immunogenicity testing will include IgG antibody responses to Na-GST-1, by a qualified indirect enzyme-linked immunosorbent assay (ELISA), on serum obtained prior to each study vaccination and CHHI, and at time points after each vaccination and after CHHI (see Appendix A); the affinity of vaccine-induced antibodies against Na-GST-1 using Surface Plasmon Resonance; the functional activity of vaccine-induced antibodies via in vitro enzyme neutralization assay; antigen-specific memory B cell responses; and, the innate immune responses to each of the TLR receptor immunostimulants.
Parasitological testing will include microscopic fecal egg detection by a qualified saline flotation technique, fecal egg counts by the McMaster method, fecal PCR for hookworm DNA, and peripheral eosinophil counts.
Recruitment and enrollment into the study will occur on an ongoing basis, with each group being recruited and vaccinated in sequence.
48 subjects will be enrolled into 4 groups of 12. Subjects will be enrolled sequentially and upon enrollment will be randomized to one of the following IP assignments in a double-blind fashion:
- Group 1 IP allocation (n=12 subjects): 12 subjects will receive 100µg Na-GST-1/Alhydrogel® delivered by IM injection in the deltoid muscle.
- Group 2 IP allocation (n=12): 12 subjects will receive Na-GST-1/Alhydrogel® plus 500µg CpG 10104 delivered by IM injection in the deltoid muscle.
- Group 3 IP allocation (n=12): 12 subjects will receive Na-GST-1/Alhydrogel® plus 5µg GLA-AF delivered by IM injection in the deltoid muscle.
- Group 4 IP allocation (n=12): 12 subjects will receive sterile saline delivered by IM injection in the deltoid muscle.
- Conditions
- Hookworm Infections
- Being tested
- Na-GST-1/Alhydrogel, Na-GST-1/Alhydrogel + CPG 10104, Na-GST-1/Alhydrogel + GLA-AF, Placebo, Albendazole
- Keywords
- Controlled infection, Na-GST-1, Hookworm vaccine
- Medical subject headings
- Hookworm Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Na-GST-1/AlhydrogelBiological
Also called Necator americanus Glutathione-S Transferase
Recombinant Necator americanus Glutathione-S Transferase adjuvanted with Alhydrogel
Na-GST-1/Alhydrogel + CPG 10104Biological
Recombinant Necator americanus Glutathione-S Transferase adjuvanted with Alhydrogel and co-administered with CPG 10104, a synthetic oligodeoxynucleotide
Na-GST-1/Alhydrogel + GLA-AFBiological
Recombinant Necator americanus Glutathione-S Transferase adjuvanted with Alhydrogel and co-administered with an aqueous formulation of Glucopyranosyl-Lipid A (GLA-AF)
PlaceboBiological
Physiological sterile saline solution
AlbendazoleDrug
Treatment with 3 daily oral doses of 400 mg albendazole at end of study.
Necator americanus Larval InoculumOther
50 infectious Necator americanus larvae applied via dermal application (challenge infection).
| Study group | Role | What they receive |
|---|---|---|
| Na-GST-1/Alhydrogel | Experimental | 100 µg Na-GST-1/Alhydrogel administered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. Receives: Biological: Na-GST-1/Alhydrogel; Drug: Albendazole; Other: Necator americanus Larval Inoculum |
| Na-GST-1/Alhydrogel + CPG 10104 | Experimental | 100 µg Na-GST-1/Alhydrogel co-administered with 500 µg CPG 10104 delivered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. Receives: Biological: Na-GST-1/Alhydrogel + CPG 10104; Drug: Albendazole; Other: Necator americanus Larval Inoculum |
| Na-GST-1/Alhydrogel + GLA-AF | Experimental | 100 µg Na-GST-1/Alhydrogel co-administered with 5 µg GLA-AF delivered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. Receives: Biological: Na-GST-1/Alhydrogel + GLA-AF; Drug: Albendazole; Other: Necator americanus Larval Inoculum |
| Saline Placebo | Placebo comparator | Sterile saline placebo delivered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. Receives: Biological: Placebo; Drug: Albendazole; Other: Necator americanus Larval Inoculum |
What is being measured
The primary outcome is the main question the study is designed to answer.
Detectable Hookworm Infection
Proportion of subjects with detectable hookworm eggs, at any time point, in fecal samples, as determined by microscopy using the qualified saline flotation technique
Measured: On Study Days 175, 182, 189, 203, 217, 231, 245, 259, 273, and 280.
Incidence of Serious Adverse Events
Frequency of study vaccine-related Serious Adverse Events from the time of the first study vaccination through approximately 10 months after the last study vaccination.
Measured: Beginning on Day 0 when the first dose is received and ending on Day 380 (final study visit).
Incidence of Solicited Injection Site and Systemic Reactogenicity
Frequency of solicited injection site and systemic reactogenicity, graded by severity, on the day of each study vaccination through 14 days after each study vaccination.
Measured: Dose 1: Days 0, 3, 7, 14; Dose 2: Days 56, 59, 63, 70; Dose 3: Days 112, 115, 119, 126
Incidence of Solicited Adverse Events
Frequency of solicited adverse events, graded by severity, on the day of CHHI through study Day 280
Measured: Day of CHHI, Day 140, and study days: 143, 147, 154, 175, 182, 189, 196, 203, 210, 217, 224, 231, 238, 245, 252, 259, 266, 273, 280. Day 280 is the day of anti-worm treatment.
Incidence of Clinical Safety Laboratory Abnormalities
Frequency of clinical safety laboratory adverse events.
Measured: Study days: 0, 14, 56, 70, 112, 126, 140, 154, 175, 189, 203, 217, 231, 259, 280.
Incidence of Unsolicited Adverse Events
Frequency of unsolicited adverse events, graded by severity, from the time of each study vaccination through approximately 1 month after each study vaccination; and from the time of CHHI through treatment with albendazole (Day 280)
Measured: From Dose 1 on Day 0 until anti-worm treatment on Day 280.
Incidence of New-onset Chronic Medical Conditions
Frequency of new-onset chronic medical conditions through approximately 10 months after the third study vaccination.
Measured: Entire duration of the study. Beginning Day 0, day of first dose, until Day 380, final study visit.
Incidence of Adverse Events of Special Interest
Frequency of Adverse Events of Special Interest through approximately 10 months after the third study vaccination.
Measured: Entire duration of the study. Beginning Day 0, day of first dose, until Day 380, final study visit.
Secondary outcomes (2)
Fecal Egg Counts
Fecal egg counts as determined by microscopy using the McMaster method, weekly from Weeks 5 through 20 post-CHHI
Measured: Week 5 and Week 20 post-CHHI. Study days: 175, 182, 189, 203, 217, 231, 245, 259, 273, and 280.
Anti-Na-GST-1 IgG Antibody Response
Anti-Na-GST-1 IgG antibody response as measured in Arbitrary Units per milliliter (AU/mL) of serum, determined by a qualified indirect enzyme-linked immunosorbent assay (ELISA) at approximately 14 days after each vaccination, and approximately 1, 2, 4, 6, 7, 8 and 10 months after the third dose. Levels of IgG antibodies against Na-GST-1 were converted to AUs by homologous interpolation of Optical Density readings at 492nm (OD492) from a standard calibration curve derived from serial dilutions of a human standard reference serum pool collected from high IgG responders (OD492 ≥ 1.000).
Measured: Study days: 14, 70, 126, 140, 175, 189, 231, 280, 320, and 380
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Jun 2017
- Study start1 Mar 2018
- Primary completion31 Dec 2024
- Study completion30 Jan 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Hookworm InfectionsStudies of the same condition, open and under way.
- More trials run by Baylor College of MedicineThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 39 participants (actual)
Sponsor and investigators
- Lead sponsor
- Baylor College of Medicine
- Sponsor type
- University, hospital or other
- Collaborators
- George Washington University, National Institute of Allergy and Infectious Diseases (NIAID)
- Responsible party
- Principal investigator, Maria Elena Bottazzi PhD, Baylor College of Medicine
- Investigators
- David Diemert, MD, Principal investigator, George Washington University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03172975
- Sponsor's protocol ID
- H-38292
- Other IDs
- U01AI129789
- Status last verified
- Feb 2026
- First submitted
- 30 May 2017
- Last updated
- 12 Mar 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: GW provided agreement with that NIAID that it will make publicly available all final research data resulting from this U01 clinical trial, in a timely fashion following closure of the clinical trial (not more than 12 months after the last subject follow-up visit). At no time will subject identifying information be made publically available.
Publications
DiRosato CK, Malkin EM, Lee SM, Erwin G, Hoeweler L, Scholte L, Bottazzi ME, Pritchard DI, Hotez PJ, Bethony JM, Diemert DJ. Na-GST-1 adsorbed on Alhydrogel co-administered with different Toll-like receptor agonists in hookworm-naive adults using a controlled human infection model in the USA: a phase 2, double-blind, randomised controlled trial. Lancet Infect Dis. 2026 Jul;26(7):692-704. doi: 10.1016/S1473-3099(26)00018-6. Epub 2026 Mar 17.
PubMed 41861834
Study at a glance
From the registry record, last updated by the sponsor on 12 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Phase 2 Study to Assess the Safety, Efficacy and Immunogenicity of Na-GST-1/Alhydrogel Co-administered With Different Toll-Like Receptor Agonists in Hookworm- Naïve Adults
- ClinicalTrials.gov ID
- NCT03172975
- Acronym / sponsor ID
- H-38292
- Conditions
- Hookworm Infections
- Keywords
- Controlled infection, Na-GST-1, Hookworm vaccine
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 39 participants (actual)
- Lead sponsor
- Baylor College of MedicineUniversity, hospital or other
- Collaborators
- George Washington University, National Institute of Allergy and Infectious Diseases (NIAID)
- Study start
- 1 Mar 2018 (actual)
- Primary completion
- 31 Dec 2024 (actual)
- Study completion
- 30 Jan 2025 (actual)
- First posted
- 1 Jun 2017 (actual)
- Results
- Posted 5 Dec 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study evaluates the efficacy, safety and immunogenicity of different formulations of the Na-GST-1 hookworm vaccine using a controlled human hookworm infection model in healthy, hookworm-naive adults.
Detailed description
Double blind, randomized, controlled, Phase 2 clinical trial in hookworm-unexposed adults living in the metropolitan area of Washington, DC. Subjects will receive three doses of the assigned vaccine formulation, or saline placebo, delivered intramuscularly on approximately Days 0, 56, and 112.
Subjects will be challenged with 50 infectious N. americanus larvae 4 weeks after 3rd vaccination. Fecal samples will be collected weekly starting 4 weeks post-challenge. Albendazole will be administered 20 weeks post-challenge to cure infections. Subjects will be followed until 10 months after their final vaccination.
Safety of vaccination will be measured from the time of each study vaccination (Day 0) through 14 days after each study vaccination by the occurrence of solicited injection site and systemic reactogenicity events. Safety of CHHI will be measure from the time of larval application (Day 140) through the first day of treatment with albendazole (Day 280).
Unsolicited non-serious adverse events (AEs) will be collected until approximately 1 month following each study vaccination and from study Day 140 (day of CHHI) through Day 280.
New-onset chronic medical conditions and Serious Adverse Events (SAEs) will be collected from the time of the first study vaccination through approximately 10 months after the third study vaccination (final visit). Clinical laboratory evaluations for safety will be performed on venous blood collected approximately 14 days after each vaccination and CHHI.
Immunogenicity testing will include IgG antibody responses to Na-GST-1, by a qualified indirect enzyme-linked immunosorbent assay (ELISA), on serum obtained prior to each study vaccination and CHHI, and at time points after each vaccination and after CHHI (see Appendix A); the affinity of vaccine-induced antibodies against Na-GST-1 using Surface Plasmon Resonance; the functional activity of vaccine-induced antibodies via in vitro enzyme neutralization assay; antigen-specific memory B cell responses; and, the innate immune responses to each of the TLR receptor immunostimulants.
Parasitological testing will include microscopic fecal egg detection by a qualified saline flotation technique, fecal egg counts by the McMaster method, fecal PCR for hookworm DNA, and peripheral eosinophil counts.
Recruitment and enrollment into the study will occur on an ongoing basis, with each group being recruited and vaccinated in sequence.
48 subjects will be enrolled into 4 groups of 12. Subjects will be enrolled sequentially and upon enrollment will be randomized to one of the following IP assignments in a double-blind fashion:
- Group 1 IP allocation (n=12 subjects): 12 subjects will receive 100µg Na-GST-1/Alhydrogel® delivered by IM injection in the deltoid muscle.
- Group 2 IP allocation (n=12): 12 subjects will receive Na-GST-1/Alhydrogel® plus 500µg CpG 10104 delivered by IM injection in the deltoid muscle.
- Group 3 IP allocation (n=12): 12 subjects will receive Na-GST-1/Alhydrogel® plus 5µg GLA-AF delivered by IM injection in the deltoid muscle.
- Group 4 IP allocation (n=12): 12 subjects will receive sterile saline delivered by IM injection in the deltoid muscle.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Na-GST-1/Alhydrogel | Experimental | Biological: Na-GST-1/Alhydrogel, Drug: Albendazole, Other: Necator americanus Larval Inoculum100 µg Na-GST-1/Alhydrogel administered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. |
| Na-GST-1/Alhydrogel + CPG 10104 | Experimental | Biological: Na-GST-1/Alhydrogel + CPG 10104, Drug: Albendazole, Other: Necator americanus Larval Inoculum100 µg Na-GST-1/Alhydrogel co-administered with 500 µg CPG 10104 delivered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. |
| Na-GST-1/Alhydrogel + GLA-AF | Experimental | Biological: Na-GST-1/Alhydrogel + GLA-AF, Drug: Albendazole, Other: Necator americanus Larval Inoculum100 µg Na-GST-1/Alhydrogel co-administered with 5 µg GLA-AF delivered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. |
| Saline Placebo | Placebo comparator | Biological: Placebo, Drug: Albendazole, Other: Necator americanus Larval InoculumSterile saline placebo delivered intramuscularly in the deltoid on study days 0, 56 and 112 followed by controlled human hookworm infection with 50 infectious Necator americanus larvae on study day 140. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Males and non-pregnant females between 18 and 45 years, inclusive.
- Good general health as determined by means of the screening procedures1.
- Available for the duration of individual subject study participation (14 months).
- Willingness to participate in the study as evidenced by signing the informed consent document.
- Able to understand and comply with planned study procedures.
Key exclusion criteria (30 listed)
- Pregnancy as determined by a positive urine human choriogonadotropin (hCG) test (if female).
- Subject unwilling to use effective contraception for a minimum of 30 days prior to vaccination and up until documentation of clearance of hookworm infection post-CHHI (if female and not surgically sterile, abstinent from intercourse with a male partner, in a monogamous relationship with a vasectomized partner, at least 2 years post-menopausal, or determined otherwise by medical evaluation to be sterile).
- Currently lactating and breast-feeding or plans to breastfeed at any given time from the first study vaccination until clearance of hookworm infection post-CHHI (if female).
- Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, gastrointestinal, diabetes, or renal disease by history, physical examination, and/or laboratory studies.
- Has a diagnosis of schizophrenia, bipolar disease or other major psychiatric condition that would make compliance with study visits/procedures difficult (e.g., subject with psychoses or history of suicide attempt or gesture in the 3 years before study entry, ongoing risk for suicide).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Na-GST-1/AlhydrogelAlso: Necator americanus Glutathione-S TransferaseRecombinant Necator americanus Glutathione-S Transferase adjuvanted with Alhydrogel | Biological | Na-GST-1/Alhydrogel |
| Na-GST-1/Alhydrogel + CPG 10104Recombinant Necator americanus Glutathione-S Transferase adjuvanted with Alhydrogel and co-administered with CPG 10104, a synthetic oligodeoxynucleotide | Biological | Na-GST-1/Alhydrogel + CPG 10104 |
| Na-GST-1/Alhydrogel + GLA-AFRecombinant Necator americanus Glutathione-S Transferase adjuvanted with Alhydrogel and co-administered with an aqueous formulation of Glucopyranosyl-Lipid A (GLA-AF) | Biological | Na-GST-1/Alhydrogel + GLA-AF |
| PlaceboPhysiological sterile saline solution | Biological | Saline Placebo |
| AlbendazoleTreatment with 3 daily oral doses of 400 mg albendazole at end of study. | Drug | Na-GST-1/Alhydrogel, Na-GST-1/Alhydrogel + CPG 10104, Na-GST-1/Alhydrogel + GLA-AF, Saline Placebo |
| Necator americanus Larval Inoculum50 infectious Necator americanus larvae applied via dermal application (challenge infection). | Other | Na-GST-1/Alhydrogel, Na-GST-1/Alhydrogel + CPG 10104, Na-GST-1/Alhydrogel + GLA-AF, Saline Placebo |
Primary outcome
Detectable Hookworm Infection
Time frame: On Study Days 175, 182, 189, 203, 217, 231, 245, 259, 273, and 280.
Proportion of subjects with detectable hookworm eggs, at any time point, in fecal samples, as determined by microscopy using the qualified saline flotation technique
Incidence of Serious Adverse Events
Time frame: Beginning on Day 0 when the first dose is received and ending on Day 380 (final study visit).
Frequency of study vaccine-related Serious Adverse Events from the time of the first study vaccination through approximately 10 months after the last study vaccination.
Incidence of Solicited Injection Site and Systemic Reactogenicity
Time frame: Dose 1: Days 0, 3, 7, 14; Dose 2: Days 56, 59, 63, 70; Dose 3: Days 112, 115, 119, 126
Frequency of solicited injection site and systemic reactogenicity, graded by severity, on the day of each study vaccination through 14 days after each study vaccination.
Incidence of Solicited Adverse Events
Time frame: Day of CHHI, Day 140, and study days: 143, 147, 154, 175, 182, 189, 196, 203, 210, 217, 224, 231, 238, 245, 252, 259, 266, 273, 280. Day 280 is the day of anti-worm treatment.
Frequency of solicited adverse events, graded by severity, on the day of CHHI through study Day 280
Incidence of Clinical Safety Laboratory Abnormalities
Time frame: Study days: 0, 14, 56, 70, 112, 126, 140, 154, 175, 189, 203, 217, 231, 259, 280.
Frequency of clinical safety laboratory adverse events.
Incidence of Unsolicited Adverse Events
Time frame: From Dose 1 on Day 0 until anti-worm treatment on Day 280.
Frequency of unsolicited adverse events, graded by severity, from the time of each study vaccination through approximately 1 month after each study vaccination; and from the time of CHHI through treatment with albendazole (Day 280)
Incidence of New-onset Chronic Medical Conditions
Time frame: Entire duration of the study. Beginning Day 0, day of first dose, until Day 380, final study visit.
Frequency of new-onset chronic medical conditions through approximately 10 months after the third study vaccination.
Incidence of Adverse Events of Special Interest
Time frame: Entire duration of the study. Beginning Day 0, day of first dose, until Day 380, final study visit.
Frequency of Adverse Events of Special Interest through approximately 10 months after the third study vaccination.
2 secondary outcomes
Fecal Egg Counts
Time frame: Week 5 and Week 20 post-CHHI. Study days: 175, 182, 189, 203, 217, 231, 245, 259, 273, and 280.
Anti-Na-GST-1 IgG Antibody Response
Time frame: Study days: 14, 70, 126, 140, 175, 189, 231, 280, 320, and 380
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Mar 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 41861834DiRosato CK, Malkin EM, Lee SM, Erwin G, Hoeweler L, Scholte L, Bottazzi ME, Pritchard DI, Hotez PJ, Bethony JM, Diemert DJ. Na-GST-1 adsorbed on Alhydrogel co-administered with different Toll-like receptor agonists in hookworm-naive adults using a controlled human infection model in the USA: a phase 2, double-blind, randomised controlled trial. Lancet Infect Dis. 2026 Jul;26(7):692-704. doi: 10.1016/S1473-3099(26)00018-6. Epub 2026 Mar 17.
- Individual participant dataSharing planned: Yes. GW provided agreement with that NIAID that it will make publicly available all final research data resulting from this U01 clinical trial, in a timely fashion following closure of the clinical trial (not more than 12 months after the last subject follow-up visit). At no time will subject identifying information be made publically available.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
David Diemert, MD principal investigator
George Washington University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Na-GST-1/Alhydrogel, Na-GST-1/Alhydrogel + CPG 10104 and Na-GST-1/Alhydrogel + GLA-AF in people with Hookworm Infections, run by Baylor College of Medicine at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 30 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 5 Dec 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Detectable Hookworm Infection (time frame: On Study Days 175, 182, 189, 203, 217, 231, 245, 259, 273, and 280.). The study lists 8 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03172975, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Mar 2026.