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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00469989
Recruitment Status : Completed
First Posted : May 7, 2007
Last Update Posted : January 11, 2008
Information provided by:
University of Nottingham

May 4, 2007
May 7, 2007
January 11, 2008
January 2007
Not Provided
Change from baseline airway responsiveness to adenosine-5-monophosphate (AMP) during the 12 weeks of the study.
Same as current
Complete list of historical versions of study NCT00469989 on Archive Site
  • 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.
Same as current
Not Provided
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Randomised Placebo Controlled Study of Effects of Therapeutic Hookworm Infection in Asthma
Randomised Placebo Controlled Study of Effects of Therapeutic Hookworm Infection in Asthma

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.

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

Not Applicable
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Care Provider, Investigator)
Primary Purpose: Treatment
Procedure: Infection with hookworm larvae
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*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Same as current
October 2007
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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
Sexes Eligible for Study: All
18 Years and older   (Adult, Older Adult)
Contact information is only displayed when the study is recruiting subjects
United Kingdom
Not Provided
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University of Nottingham
Not Provided
Principal Investigator: John Britton University of Nottingham
Principal Investigator: David Pritchard University of Nottingham
University of Nottingham
January 2008

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP