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Randomised Placebo Controlled Study of Effects of Therapeutic Hookworm Infection in Asthma

This study has been completed.
Information provided by:
University of Nottingham Identifier:
First received: May 4, 2007
Last updated: January 2, 2008
Last verified: January 2008

There has been considerable debate over the last 30 years about the interaction between asthma and parasitic infection. It has been suggested that at least part of the reason for the increasing prevalence of asthma in the developed world is a decrease in parasite infections resulting from improved living conditions with economic development. Our previous studies in Ethiopia suggest that hookworm infection may be particularly important in this process.

To establish definitively whether parasites can protect against allergic disease, and specifically asthma, ultimately requires a randomised clinical trial of parasite infection in patients with asthma. We, the researchers at the University of Nottingham, have completed a study in normal volunteers to establish the dose of hookworms necessary to generate infection at the level shown to be protective in population surveys, and shown that infection is well tolerated. In addition, we have recently completed a randomized placebo-controlled clinical trial of hookworm infection in allergic patients with rhinitis which showed that there was no negative effect on bronchial responsiveness during the phase in the lifecycle where the hookworm larvae migrate through the lungs. Consequently, are now proceeding with the definitive randomized placebo-controlled trial of hookworm infection in people with asthma. This study will also provide us with the opportunity to investigate the cellular mechanisms of the effect of hookworm infection on the immune system.

Condition Intervention
Asthma Procedure: Infection with hookworm larvae

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Care Provider, Investigator)
Primary Purpose: Treatment
Official Title: Randomised Placebo Controlled Study of Effects of Therapeutic Hookworm Infection in Asthma

Resource links provided by NLM:

Further study details as provided by University of Nottingham:

Primary Outcome Measures:
  • Change from baseline airway responsiveness to adenosine-5-monophosphate (AMP) during the 12 weeks of the study.

Secondary Outcome Measures:
  • Change in peak flow variability, asthma symptom scores, asthma medication usage, allergen skin wheal response,total and specific IgE titres, acidic mammalian chitinase, cytokine profiles, other inflammatory markers
  • occurrence of adverse effects.

Estimated Enrollment: 30
Study Start Date: January 2007
Study Completion Date: October 2007
Detailed Description:

Epidemiological evidence suggests that human hookworm infection is associated with a reduced risk of asthma and allergic disease. This association is potentially important not only to understanding the aetiology of asthma and allergic disease, but also because it suggests that hookworms or their products might be therapeutically effective in these conditions. To test the hypothesis that hookworms protect against asthma ultimately requires a clinical trial.

We have carried out a dose-ranging study to establish the dose of hookworm larvae necessary to generate infection at the intensity shown to be protective in epidemiological studies, with acceptable side effects. We have also completed a randomized controlled clinical trial of hookworm infection in people with allergic rhinoconjunctivitis and have shown that there is no significant change in airway responsiveness during the lung migration phase of the hookworm life cycle. We are now performing the definitive study which is a randomized placebo-controlled trial of the effects of therapeutic hookworm infection in people with asthma. During this study, we will be monitoring various indicators of asthma control but will also be able to measure a range of relevant immunological parameters to explore the relation between these parameters and expression of the allergic and asthmatic phenotypes


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Clinical diagnosis of asthma
  • Use of regular inhaled corticosteroid treatment to a maximum of 1000mcg beclomethasone or equivalent per day
  • Measurable airway responsiveness to AMP
  • Negative hookworm serology
  • Positive skin prick tests to D.pteronyssinum, cat fur or grass pollen

Exclusion Criteria:

  • Possible or planned pregnancy or breastfeeding
  • Use of regular oral corticosteroids or immunosuppressive medication
  • Anemia
  • History of anaphylaxis
  Contacts and Locations
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Please refer to this study by its identifier: NCT00469989

United Kingdom
University of Nottingham
Nottingham, United Kingdom, NG5 1PB
Sponsors and Collaborators
University of Nottingham
Principal Investigator: John Britton University of Nottingham
Principal Investigator: David Pritchard University of Nottingham
  More Information Identifier: NCT00469989     History of Changes
Other Study ID Numbers: RB08A3
Study First Received: May 4, 2007
Last Updated: January 2, 2008

Keywords provided by University of Nottingham:
immune system
hookworm infection
parasite infection

Additional relevant MeSH terms:
Hookworm Infections
Bronchial Diseases
Respiratory Tract Diseases
Lung Diseases, Obstructive
Lung Diseases
Respiratory Hypersensitivity
Hypersensitivity, Immediate
Immune System Diseases
Strongylida Infections
Secernentea Infections
Nematode Infections
Parasitic Diseases processed this record on September 21, 2017