Efficacy of Na-GST-1/Alhydrogel Hookworm Vaccine Assessed by Controlled Challenge Infection

January 19, 2024 updated by: Maria Elena Bottazzi PhD, Baylor College of Medicine

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.

Study Overview

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 Type

Interventional

Enrollment (Actual)

39

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • District of Columbia
      • Washington, District of Columbia, United States, 20037
        • George Washington University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Males and non-pregnant females between 18 and 45 years, inclusive.
  2. Good general health as determined by means of the screening procedures1.
  3. Available for the duration of individual subject study participation (14 months).
  4. Willingness to participate in the study as evidenced by signing the informed consent document.
  5. Able to understand and comply with planned study procedures.

Exclusion Criteria:

  1. Pregnancy as determined by a positive urine human choriogonadotropin (hCG) test (if female).
  2. 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).
  3. 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).
  4. Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, gastrointestinal, diabetes, or renal disease by history, physical examination, and/or laboratory studies.
  5. 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).
  6. 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).
  7. Laboratory evidence of liver disease (alanine aminotransferase [ALT] greater than 1.25-times the upper reference limit).
  8. 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).
  9. 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).
  10. 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.
  11. 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).
  12. Volunteer has had medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 24 months.
  13. Positive fecal occult blood test at screening.
  14. Infection with a pathogenic intestinal helminth as determined by stool examination for ova and parasites at screening.
  15. History of iron deficiency anemia or laboratory evidence of iron deficiency (serum ferritin concentration below the lower reference limit).
  16. History of hypoalbuminemia.
  17. History of a severe allergic reaction or anaphylaxis.
  18. 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.
  19. Positive test for hepatitis B surface antigen (HBsAg).
  20. Positive confirmatory test for HIV infection.
  21. Positive confirmatory test for hepatitis C virus (HCV) infection.
  22. 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.
  23. 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.
  24. Receipt of immunoglobin or other blood products (with exception of Rho D immunoglobulin) within 90 days of the planned first study vaccination.
  25. Known allergy to albendazole, amphotericin B or gentamicin.
  26. History of previous infection with hookworm or continuous residence for more than 6 months in a community where hookworm is endemic.
  27. Current or past scars, tattoos, or other disruptions of skin integrity at the intended site of larval application.
  28. Previous receipt of the Na-GST-1/Alhydrogel® hookworm vaccine.
  29. History of a surgical splenectomy.
  30. 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).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Na-GST-1/Alhydrogel
100 µg ˆNaˆ-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.
Recombinant ˆNecator americanusˆ Glutathione-S Transferase adjuvanted with Alhydrogel
Other Names:
  • Necator americanus Glutathione-S Transferase
Treatment with 3 daily oral doses of 400 mg albendazole at end of study.
50 infectious Necator americanus larvae applied via dermal application (challenge infection).
Experimental: Na-GST-1/Alhydrogel + CPG 10104
100 µg ˆNaˆ-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.
Treatment with 3 daily oral doses of 400 mg albendazole at end of study.
50 infectious Necator americanus larvae applied via dermal application (challenge infection).
Recombinant ˆNecator americanusˆ Glutathione-S Transferase adjuvanted with Alhydrogel and co-administered with CPG 10104, a synthetic oligodeoxynucleotide
Experimental: Na-GST-1/Alhydrogel + GLA-AF
100 µg ˆNaˆ-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.
Treatment with 3 daily oral doses of 400 mg albendazole at end of study.
50 infectious Necator americanus larvae applied via dermal application (challenge infection).
Recombinant ˆNecator americanusˆ Glutathione-S Transferase adjuvanted with Alhydrogel and co-administered with an aqueous formulation of Glucopyranosyl-Lipid A (GLA-AF)
Placebo Comparator: Saline Placebo
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.
Treatment with 3 daily oral doses of 400 mg albendazole at end of study.
50 infectious Necator americanus larvae applied via dermal application (challenge infection).
Physiological sterile saline solution

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Detectable hookworm infection
Time Frame: Week 20 post-CHHI
Proportion of subjects with detectable hookworm eggs, at any time point, in fecal samples, as determined by microscopy using the qualified saline flotation technique
Week 20 post-CHHI
Incidence of Serious Adverse Events
Time Frame: Day 280
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.
Day 280
Incidence of solicited injection site and systemic reactogenicity
Time Frame: Day 14 post-vaccination
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.
Day 14 post-vaccination
Incidence of solicited adverse events
Time Frame: Day 280
Frequency of solicited adverse events, graded by severity, on the day of CHHI through study Day 280
Day 280
Incidence of clinical safety laboratory abnormalities
Time Frame: Day 14 post-vaccination
Frequency of clinical safety laboratory adverse events.
Day 14 post-vaccination
Incidence of unsolicited adverse events
Time Frame: 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)
Day 280
Incidence of new-onset chronic medical conditions
Time Frame: Day 280
Frequency of new-onset chronic medical conditions through approximately 10 months after the third study vaccination.
Day 280
Incidence of Adverse Events of Special Interest
Time Frame: Day 280
Frequency of Adverse Events of Special Interest through approximately 10 months after the third study vaccination.
Day 280

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Fecal egg counts
Time Frame: Week 5 and Week 20 post-CHHI
Fecal egg counts as determined by microscopy using the McMaster method, weekly from Weeks 5 through 20 post-CHHI
Week 5 and Week 20 post-CHHI
Anti-Na-GST-1 IgG antibody response
Time Frame: 14 days after each vaccination, and approximately 1, 2, 4, 6, 7, 8 and 10 months after the third dose
Anti-Na-GST-1 IgG antibody response, 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
14 days after each vaccination, and approximately 1, 2, 4, 6, 7, 8 and 10 months after the third dose
Anti-Na-GST-1 IgG antibody affinity
Time Frame: 14 days after each vaccination, and approximately 1, 2, 4, 6, 7, 8 and 10 months after the third dose
Affinity of the antibody interactions with recombinant Na-GST-1 antigen at approximately 14 days after each vaccination, and approximately 1, 2, 4, 6, 7, 8 and 10 months after the third dose.
14 days after each vaccination, and approximately 1, 2, 4, 6, 7, 8 and 10 months after the third dose
Memory B cells specific for Na-GST-1
Time Frame: 7 and 14 days following each vaccination; on day of CHHI; and then 7 and 14 days, and 5, 7, 13, and 20 weeks post-CHHI
Production of memory B cells specific for Na-GST-1 on days of vaccination; approximately 7 and 14 days following each vaccination; on day of CHHI; and then 7 and 14 days, and 5, 7, 13, and 20 weeks post-CHHI.
7 and 14 days following each vaccination; on day of CHHI; and then 7 and 14 days, and 5, 7, 13, and 20 weeks post-CHHI
Innate immune responses
Time Frame: Approximately 7 and 14 days following each vaccination; on day of CHHI; and then 7 and 14 days, and 5, 7, 13, and 20 weeks post-CHHI
Innate immune responses on days of vaccination approximately 7 and 14 days following each vaccination; on day of CHHI; and then 7 and 14 days, and 5, 7, 13, and 20 weeks post-CHHI
Approximately 7 and 14 days following each vaccination; on day of CHHI; and then 7 and 14 days, and 5, 7, 13, and 20 weeks post-CHHI

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: David Diemert, MD, George Washington University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 1, 2018

Primary Completion (Actual)

May 31, 2023

Study Completion (Estimated)

July 31, 2024

Study Registration Dates

First Submitted

May 30, 2017

First Submitted That Met QC Criteria

May 30, 2017

First Posted (Actual)

June 1, 2017

Study Record Updates

Last Update Posted (Actual)

January 22, 2024

Last Update Submitted That Met QC Criteria

January 19, 2024

Last Verified

January 1, 2024

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

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.

IPD Sharing Time Frame

Within 12 months of final study visit.

IPD Sharing Access Criteria

To be determined.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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