Randomised Controlled Clinical Trials of the Effect of Therapeutic Hookworm Infection in Allergic Rhinoconjunctivitis

May 4, 2007 updated by: University of Nottingham

Randomised Controlled Clinical Trial of the Effect of Therapeutic Hookworm Infection in Allergic Rhinoconjunctivitis

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. We now propose two randomised placebo-controlled double blind clinical trials. The first will test the effectiveness of hookworm infection in reducing symptoms in allergic patients with rhinitis, and will also serve to allow us to check the likely safety of hookworm infection in asthma. Assuming that the results of this study are favourable, we will then carry out a trial of hookworm infection in asthma. We will also take the opportunity during both of these studies to investigate the cellular mechanisms of the effect of hookworm infection on the immune system.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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, and now propose to test the effect of 12 weeks of hookworm infection at this level of intensity in two randomised placebo controlled clinical trials. The first will be in patients with allergic rhinoconjunctivitis, to determine whether hookworm infection improves rhinitis symptoms and also, because these patients will have measurable airway responsiveness, to determine whether airway responsiveness changes during the lung migration phase of the hookworm life cycle. If this study confirms that hookworm infection does not increase airway responsiveness, we will proceed to a similar trial in patients with asthma.

In both studies we will also measure a range of relevant immunological parameters to explore the relation between these parameters and expression of the allergic and asthmatic phenotypes.

Study Type

Interventional

Enrollment

30

Phase

  • Not Applicable

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

  • United Kingdom
      • Nottingham, United Kingdom, NG5 1PB
        • University of Nottingham

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 and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Symptoms of allergic rhinitis
  • Measurable airway responsiveness to AMP
  • Negative hookworm serology
  • Positive skin prick tests to D.pteronyssinum, cat fur or grass pollen

Exclusion Criteria:

  • History of asthma
  • History of anaemia
  • History of severe allergic reaction or anaphylaxis
  • Possible or planned pregnancy

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Maximum change from baseline in airway responsiveness to adenosine 5'-monophosphate (AMP) during the lung migration phase of hookworm infection.

Secondary Outcome Measures

Outcome Measure
Change from baseline in rhinoconjunctivitis quality of life questionnaire score
allergen skin wheal response
mean daily peak flow
total- and specific serum IgE titres
acidic mammalian chitinase, cytokine profiles, other inflammatory markers
occurrence of adverse effects

Collaborators and Investigators

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

Sponsor

University of Nottingham

Investigators

  • Principal Investigator: David Prichard, University of Nottingham

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

September 1, 2005

Study Completion (Actual)

November 1, 2006

Study Registration Dates

First Submitted

September 30, 2005

First Submitted That Met QC Criteria

September 30, 2005

First Posted (Estimate)

October 4, 2005

Study Record Updates

Last Update Posted (Estimate)

May 7, 2007

Last Update Submitted That Met QC Criteria

May 4, 2007

Last Verified

April 1, 2005

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • GR076306

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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