Immune Response of Individuals Vaccinated With Hypoallergenic Derivatives of the Major Birch Pollen Allergen, Bet v 1

May 12, 2011 updated by: Medical University of Vienna

The only disease-modifying treatment for allergic disorders nowadays is allergen-specific immunotherapy (SIT). To induce hyporesponsiveness increasing doses of the disease-eliciting allergens are applied. One major problem of this treatment is, that it has to combat with an already established immune response against the disease-eliciting allergen. To circumvent this problem the investigators want to perform the proof of principle study towards prophylactic treatment. Prophylactic vaccination is used since many years for many infectious diseases. The investigators want to adopt this successful principle for the treatment of type I allergies.

For this purpose non-allergic healthy individuals will be immunized with adjuvant-bound hypoallergenic derivatives of the major birch pollen allergen, Bet v 1. As usual for allergen-specific immunotherapy, injections will be applied subcutaneously. Three injections in one-monthly intervals will be given to establish the immune response and a further injection after one year will determine how the vaccine-induced immune response can be boosted.

The vaccine will be composed of an equimolar mixture of two adjuvant-bound hypoallergenic derivatives of the major birch pollen allergen, Bet v 1. The first investigational product (IP) designated as Bet v 1aF1 is a protein of 73 amino acid residues and represents the first half (1-73aa) of the Bet v 1 molecule. The second IP, Bet v 1aF2, is a protein of 86 amino acid residues and represents the second half (74-160aa) of Bet v 1. Both proteins are expressed in Escherichia coli. The hypoallergenic derivatives lost their IgE binding capacities by the disruption of the conformational IgE epitopes of the Bet v 1 molecule.

In several preclinical and clinical studies it has been shown that the two hypoallergenic fragments, Bet v 1aF1 and Bet v 1aF2 have a strongly reduced allergenic reactivity and almost no sensitization potential, requisite for a prophylactic treatment. In a multi-centre placebo-controlled double blind clinical trial including 124 allergic patients no relevant sensitization against new epitopes could be observed after vaccination of the Alum-bound Bet v 1 derivatives.

In contrast, the vaccine induced a strong IgG response in animals as well as in clinical studies. Vaccine-induced antibodies showed protective properties as they could inhibit the binding of allergic patients' IgE. An improvement of clinical symptoms and a reduction of the skin reactivity was correlated with an increase of IgG antibodies and could be shown only in actively treated patients in a multi-centre placebo-controlled double blind clinical trial.

The investigational products will be tested in a Phase I clinical trial for prophylactic allergy vaccination in healthy non-allergic subjects. The two IPs will be coupled either to Alum and an equimolar mixture will be injected subcutaneously. The immune responses will be compared to placebo. In total 20 non-allergic healthy male subjects (10 per group) will be included in this clinical trial. For safety precautions the subjects will be monitored by skin prick testing using the two uncoupled IPs and commercial birch pollen extract in short intervals to recognize possible vaccine-induced sensitizations. The primary endpoint of phase I clinical trial is the evolution of Bet v 1-specific and Bet v 1 fragment-specific IgG1-4, IgE and IgM antibody levels in serum and in nasal fluids after vaccination of rBet v 1 derivatives.

Study Overview

Study Type

Interventional

Enrollment (Anticipated)

20

Phase

  • Phase 1

Contacts and Locations

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

Study Contact

Study Locations

      • Vienna, Austria, 1090
        • Medical University of Vienna, Department of Pathophysiology
        • Contact:
        • Sub-Investigator:
          • Katharina Marth, MD
        • Principal Investigator:
          • Rudolf Valenta, MD
      • Vienna, Austria, 1150
        • Allergiezentrum Wien West
        • Contact:
          • Friedrich Horak, MD
          • Phone Number: +43676842135219
        • Principal Investigator:
          • Friedrich Horak, MD

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 50 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Male

Description

Inclusion Criteria:

  1. Age: 18 to 50 years
  2. Male
  3. No history of allergy
  4. Negative skin prick tests for birch pollen and Bet v 1-fragments
  5. Negative IgE for birch pollen and rBet v 1, mugwort pollen house dust mite, cat, alder pollen, hazel pollen, timothy grass pollen
  6. Healthy individuals according to history, physical examination and routine laboratory findings
  7. Capable of giving informed consent, which includes compliance with the requirements and restrictions listed in the consent form
  8. Available to complete the study

Exclusion Criteria:

  1. History of drug or other allergy
  2. Autoimmune disease, immune-defects including immuno-suppression, immune complex-induced immunopathies
  3. Contra-indication for adrenaline
  4. Long-term treatment with systemic corticosteroids, immunosuppressive drugs, tranquilizers or psychoactive drugs
  5. Active tuberculosis
  6. Multiple sclerosis
  7. Severe psychological disorders
  8. The subject has participated in a study involving an investigational drug within 90 days prior to visit 1
  9. The subject is concurrently and within 6 months participating in another clinical study in which the subject is or will be exposed to an investigational or a non-investigational drug
  10. The subject has donated a unit of blood (450ml) within the previous three months
  11. Has a positive history for human immunodeficiency virus (HIV) antibodies or active hepatitis B or C
  12. The subject is at risk of non-compliance with the study procedures/restrictions

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: Single Group Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Bet v 1aF1 + Bet v 1aF2 -Alum
subcutaneous injection of equimolar mixture (20µg each) of Bet v 1aF1-Alum and Bet v 1aF2-Alum, three times in monthly intervals and a booster injection after one year
Placebo Comparator: Alum-Placebo
subcutaneous injection of Alum-Placebo, three times in monthly intervals and a booster injection after one year

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evolution of Bet v 1-, and Bet v 1- fragments -specific total serum IgG antibody levels after vaccination with the Bet v 1-derivatives.
Time Frame: after 12 months and after 24 months
Measurement of vaccination-induced Bet v 1-, and Bet v 1- fragments -specific serum IgG antibody
after 12 months and after 24 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evolution of Bet v 1-, and Bet v 1- fragments -specific serum IgM, IgA, IgE and IgG1-4 antibody levels after vaccination with the Bet v 1-derivatives
Time Frame: after 12 months and after 24 months
Measurement of vaccination-induced Bet v 1-, and Bet v 1- fragments -specific serum IgM, IgA, IgE and IgG1-4 antibody levels
after 12 months and after 24 months
Evolution of Bet v 1-, and Bet v 1- fragments -specific IgM, IgA, IgE and IgG1-4 antibody levels after vaccination with the Bet v 1-derivatives in nasal fluids
Time Frame: after 12 months and after 24 months
Measurement of vaccination-induced Bet v 1-, and Bet v 1- fragments -specific IgM, IgA, IgE and IgG1-4 antibody levels in nasal fluids
after 12 months and after 24 months
Identification of epitope-specificity and magnitude of the immune response and its possible dependence on the subjects' HLA background
Time Frame: after 12 months and after 24 months
after 12 months and after 24 months
Determination of the capacity of treatment-induced antibodies to inhibit the binding of IgE from Bet v 1-sensitized patient to Bet v 1 wildtype.
Time Frame: after 12 months and after 24 months
after 12 months and after 24 months
Determination if vaccination with hypoallergenic Bet v 1 derivatives induces skin reactivity to natural, birch pollen-derived Bet v 1 by skin prick testing
Time Frame: after 12 months and after 24 months
after 12 months and after 24 months
Identification of the type and epitope specificity of the cellular immune responses (Th1/Th2/T regulatory cell development) and the cytokine profile in vaccinated individuals
Time Frame: after 12 months and after 24 months
after 12 months and after 24 months

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Friedrich Horak, MD, Allergiezentrum Wien West
  • Study Director: Rudolf Valenta, MD, Medical University of Vienna

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

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

August 1, 2011

Primary Completion (Anticipated)

August 1, 2012

Study Completion (Anticipated)

December 1, 2013

Study Registration Dates

First Submitted

May 9, 2011

First Submitted That Met QC Criteria

May 12, 2011

First Posted (Estimate)

May 16, 2011

Study Record Updates

Last Update Posted (Estimate)

May 16, 2011

Last Update Submitted That Met QC Criteria

May 12, 2011

Last Verified

April 1, 2011

More Information

Terms related to this study

Other Study ID Numbers

  • 2411.V2.2009
  • 2009-015611-40 (EudraCT Number)

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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