ClinicalTrials.gg
CompletedNCT01717950Updated Jul 31, 2019

Safety and Immunogenicity of the Na-APR-1 Hookworm Vaccine in Healthy Adults

A Phase 1 interventional study of Na-APR-1 (M74)/Alhydrogel® and Gluco-Pyranosylphospho-Lipid A Aqueous Formulation in Hookworm Infection and Hookworm Disease, sponsored by Baylor College of Medicine. Completed at 1 site in United States. Open to participants aged 18 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2019-07-31.

Sponsored by Baylor College of Medicine · Phase 1, Interventional, and Prevention

Phase
Phase 1
Study type
Interventional
Enrollment
40
Allocation
Non-randomized
Ages
18 Years to 50 Years
Sex
All
01

Study summary

Hookworms digest hemoglobin from erythrocytes for use as an energy source via a proteolytic cascade that begins with the aspartic protease, APR-1. Vaccination with recombinant APR-1 has protected animals from infection in challenge studies. This study will evaluate the safety and immunogenicity of two formulations of Na-APR-1 (M74) in healthy adult volunteers when co-administered with different concentrations of the immunostimulant GLA-AF.

Read the detailed description

Open-label, dose-escalation phase 1 clinical trial in healthy, hookworm-naïve adults:

  • Study site: George Washington Medical Faculty Associates, Washington, DC
  • Number of participants: 40 in 2 cohorts of 20.

In Cohort 1 five (5) volunteers will receive 30 µg Na-APR-1 (M74) /Alhydrogel®, five (5) will receive 30 µg Na-APR-1 (M74)/Alhydrogel® plus 2.5 µg GLA-AF, and ten (10) will receive 30 µg Na-APR-1 (M74) /Alhydrogel® plus 5 µg GLA-AF. In Cohort 2 five (5) volunteers will receive 100 µg Na-APR-1 (M74)/Alhydrogel®, five (5) will receive 100 µg Na-APR-1 (M74) /Alhydrogel® plus 2.5 µg GLA-AF, and ten (10) will receive 100 µg Na-APR-1 (M74)/Alhydrogel® plus 5 µg GLA-AF.

The cohorts will be enrolled in a staggered fashion with safety data assessed prior to the Na-APR-1 dose escalation from 30 to 100 µg. In addition, within each cohort, vaccinations will be staggered such that formulations containing 0, 2.5, and 5 µg GLA-AF will be tested sequentially: for example, those receiving Na-APR-1 (M74)/Alhydrogel® in combination with 2.5 µg GLA-AF will be vaccinated no sooner than 3 days after the last volunteer is vaccinated with the formulation containing no GLA-AF, whereas those vaccinated with Na-APR-1 (M74)/Alhydrogel® plus 5 µg GLA-AF will be vaccinated no sooner than 7 days after the last one receives the 2.5 µg GLA-AF formulation.

  • Immunization schedule: Study days 0, 56 and 112.
  • Route: IM in the deltoid muscle.
  • Doses of Na-APR-1 (M74) to be tested: 30 and 100 µg.
  • Doses of Alhydrogel®: 240 and 800 µg for the 30 and 100 µg doses of Na-APR-1 (M74), respectively.
  • Doses of GLA-AF to be tested: 2.5 µg and 5 µg.
  • Study duration: 44 weeks (10 months) per study participant; total duration of the study estimated at approximately 13 months.
02

Conditions studied

  • Hookworm Infection
  • Hookworm Disease

Keywords

  • Human Hookworm
  • Necator americanus
  • Hookworm
  • Hookworm Disease
  • Iron-deficiency anemia
  • Soil-transmitted helminth infection
  • Neglected Tropical Disease
  • Na-APR-1
03

In context

Hookworm Infections

39 studies on the registry are indexed under Hookworm Infections; 5 are open to participants now.

This study's enrollment of 40 is below the median of 182 across 36 interventional studies indexed under Hookworm Infections.

Browse Hookworm Infections studies →

Lead sponsor

Baylor College of Medicine is the lead sponsor of 747 studies on the registry; 110 are open to participants now.

Of its 84 completed or terminated interventional studies of FDA-regulated products, 45 (54%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 50 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Males or females between 18 and 50 years, inclusive.
  • Good general health as determined by means of the screening procedure.
  • Available for the duration of the trial (44 weeks).
  • Willingness to participate in the study as evidenced by signing the document.

Exclusion criteria

Exclusion Criteria:

  • Pregnancy as determined by a positive urine human choriogonadotropin (hCG) (if female).
  • Participant unwilling to use reliable methods up until one month following the third immunization (if female and not surgically sterile, abstinent or at least 2 years ).
  • Currently lactating and breast-feeding (if female).
  • Evidence of neurologic, cardiac, pulmonary, hepatic, rheumatologic, , diabetes, or renal disease by history, physical examination, and/or laboratory studies.
  • Known or suspected immunodeficiency.
  • Laboratory evidence of liver disease ( [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 ( \<11.5 g/dl [females] or \<12.5 g/dl [males]; absolute leukocyte count \<3600/mm3 or >10.7 x 103/mm3; [ANC] \<1700/ mm3; absolute lymphocyte count \<700/mm3; or count \<140,000/mm3).
  • Laboratory evidence of a coagulopathy ( 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.
  • Participation in another vaccine or drug trial within 30 days of starting this study.
  • 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 first vaccination in the study.
  • Positive ELISA for surface antigen (HBsAg).
  • Positive confirmatory test for infection.
  • Positive confirmatory test for virus (HCV) infection.
  • Use of (excluding topical or nasal) or drugs within 30 days of the volunteer's expected first vaccination in this study.
  • Receipt of a within 4 weeks or a killed vaccine within 2 weeks prior to the volunteer's expected first vaccination in the study.
  • History of a surgical splenectomy.
  • Receipt of blood products within the past 6 months.
  • History of previous infection with hookworm or residence for more than 6 months in a hookworm-endemic area.
Terms in these criteria, in plain language(17)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

Postmenopausal

Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

Autoimmune disease

A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.

Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).

Absolute neutrophil count (ANC)

The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.

It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

INR, PT and aPTT (clotting tests)

Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.

Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Live vaccines

Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.

05

Study design

Phase
Phase 1
Primary purpose
Prevention
Allocation
Non-randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
40 participants (actual)

Study arms

  • Experimental
    30 µg Na-APR-1 (M74)/Alhydrogel®

    Biological: Na-APR-1 (M74)/Alhydrogel®

  • Experimental
    30 µg Na-APR-1 (M74)/Alhydrogel® plus 2.5 µg GLA-AF

    Biological: Na-APR-1 (M74)/Alhydrogel® · Biological: Gluco-Pyranosylphospho-Lipid A Aqueous Formulation

  • Experimental
    30 µg Na-APR-1 (M74)/Alhydrogel® plus 5.0 µg GLA-AF

    Biological: Na-APR-1 (M74)/Alhydrogel® · Biological: Gluco-Pyranosylphospho-Lipid A Aqueous Formulation

  • Experimental
    100 µg Na-APR-1 (M74)/Alhydrogel®

    Biological: Na-APR-1 (M74)/Alhydrogel®

  • Experimental
    100 µg Na-APR-1 (M74)/Alhydrogel® plus 2.5 µg GLA-AF

    Biological: Na-APR-1 (M74)/Alhydrogel® · Biological: Gluco-Pyranosylphospho-Lipid A Aqueous Formulation

  • Experimental
    100 µg Na-APR-1 (M74)/Alhydrogel® plus 5.0 µg GLA-AF

    Biological: Na-APR-1 (M74)/Alhydrogel® · Biological: Gluco-Pyranosylphospho-Lipid A Aqueous Formulation

Interventions

  • BiologicalNa-APR-1 (M74)/Alhydrogel®

    The Na-APR-1 (M74) candidate vaccine contains the recombinant Na-APR-1 (M74) protein expressed by Nicotiana plants. Purified Na-APR-1 (M74) was subsequently adsorbed onto aluminum hydroxide gel (Alhydrogel®) and suspended in a solution containing 10 mM imidazole, 150 mM sodium chloride and 0.3% Empigen BB, with pH 7.4 ± 0.1. The final concentration of Na-APR-1 (M74) in the drug product is 0.1 mg/ml, whereas that of Alhydrogel® is 0.8 mg/ml. Different doses of Na-APR-1 (M74) will be delivered by injecting different volumes of the 0.1 mg/ml Na-APR-1 (M74) preparation.

    Also known as: Na-APR-1, Necator americanus Aspartic Protease-1

  • GLA-AF contains a synthetic monophosphoryl lipid A (MPL) molecule that has Toll-Like Receptor-4 agonist activity. MPL is itself derived from the lipopolysaccharide (LPS) of Salmonella minnesota, a natural TLR4 agonist that is pyrogenic and can induce toxic shock. LPS, and more specifically, its lipid A component, has long been known for its strong adjuvant effects; however, its high toxicity has precluded its use in a vaccine formulation.

    Also known as: GLA-AF

06

What researchers measure

Primary outcomes

  1. Vaccine-related Adverse Events

    The frequency of immediate, systemic, and local injection site adverse events will be summarized. Adverse events will be assessed by study team members at 1 hour post-vaccination as well as 3, 7, 14, and 28 days following each vaccination. In addition, study participants will be asked to complete symptom diaries for the 7 days after each vaccination.

    Time frame: Day 290

Secondary outcomes

  1. IgG antibody response to Na-APR-1

    Dose and formulation of Na-APR-1 that generates the highest IgG antibody response at Day 126 (14 days after final vaccination), as determined by an indirect enzyme-linked immunosorbent assay (ELISA).

    Time frame: 14 days after final vaccination

  2. B cell response to Na-APR-1

    Dose and formulation of the Na-APR-1 (M74) vaccine that results in the highest production of Na-APR-1 (M74) specific B cells and subtypes (memory or plasma).

    Time frame: Study Days 14, 70, 126, 140 and 290

  3. Exploratory cellular immune response to Na-APR-1

    Exploratory studies of the cellular immune responses to the Na APR-1 (M74) antigen both before and after immunization.

    Time frame: Study Days 14, 70, 126, 140 and 290

07

Study locations

1 site
  • George Washington University Medical Faculty Associates
    Washington, District of Columbia 20036, United States
08

Timeline

Tracking since Sep 25, 2026
Not marked actual or estimatedDates not marked actual or estimated

The record gives a start of Sep 2013, a primary completion of Jun 2015 and a completion of Sep 2015. It does not say whether these dates are actual or estimated.

How these figures are worked out, and which studies are left out of them.

Registered
Oct 25, 2012
First posted
Oct 31, 2012
Start
Sep 2013
Primary completionActual
Jun 2015
CompletionActual
Sep 2015
Last update
Jul 31, 2019
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Jul 31, 2019, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT01717950
Responsible party
Maria Elena Bottazzi PhD (Sponsor, Baylor College of Medicine) — Principal investigator
First posted
Oct 31, 2012
Start date
Sep 2013
Primary completion
Jun 2015
Completion
Sep 2015
Last update
Jul 31, 2019

Study contacts

David J Diemert, MD
principal investigator · George Washington University

Oversight

Data monitoring committee
Yes
View the source record on ClinicalTrials.gov ↗

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