Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT04078009 |
Other study ID # |
19IC5338 |
Secondary ID |
|
Status |
Completed |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
September 26, 2019 |
Est. completion date |
August 28, 2020 |
Study information
Verified date |
August 2021 |
Source |
Imperial College London |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
Hay fever affects 1 in 4 of the UK population and has significant effects on the quality of
life of sufferers. Allergy to grass pollen is the most common cause. A detailed understanding
of the mechanisms involved during allergic reactions to pollens in hay fever sufferers may
provide improvements in diagnosis, drug treatment and assessment of their response to
treatment.
Controlled exposures to allergens such as grass pollen can provide important information on
the mechanisms of allergic inflammation and may be used to assess the success of anti-allergy
treatments.
Nasal allergen challenge (NAC) is a useful tool in the investigation of allergic rhinitis,
including grass pollen-induced seasonal allergic rhinitis (hay fever). NAC is performed by
installation of a very small amount of grass pollen extract into the nose in order to
reproduce mild and short-lived symptoms such as nasal itch, sneezing, runny nose and nasal
congestion that you experience in a more severe form during natural exposure to grass pollen
during the summer. Nasal allergen challenge has allowed us to explore the mechanism of hay
fever and to provide a rapid and reliable method for investigating new potential treatments
for hay fever.
Nasal allergen Challenge is a very well-standardised and safe procedure that has been
performed within the department of Allergy and Clinical Immunology at Imperial College and
Royal Brompton Hospital for many years.
Unfortunately the grass pollen extract ('Aquagen') that we have routinely used for nasal
challenge has been discontinued and is therefore no longer available. The present study
involves testing an alternative source of the grass pollen extract in the form of 'Grazax'
which is a freeze-dried tablet that is highly standardised and should enable us to give an
identical amount of grass pollen extract for the purpose of nasal challenge. We plan a
'head-to-head' comparison of the two extracts in nasal challenge in order to confirm that the
two sources of allergen are equivalent thereby enabling us to use Grazax as the source of
grass pollen extract for our nasal challenge studies in the future.
Description:
Nasal allergen challenge (NAC) is a useful tool in the investigation of allergic rhinitis,
including grass pollen-induced seasonal allergic rhinitis (hay fever). We have experience in
using NAC to investigate the clinical and immunological effects of allergen exposure and in
using NAC as a surrogate outcome to assess the efficacy of treatments for allergic rhinitis.
The procedure is safe and well tolerated. In order for NAC to be a valid tool, it is
essential that the allergen extracts used are standardised in terms of concentration and
stability in solution. We have previously used an extract of Timothy Grass (Phleum pratense)
pollen, Aquagen (ALK-Abello, Denmark). Aquagen is supplied as a dry powder, to be
reconstituted prior to use by dissolving in an albumin-based diluent. Unfortunately, Aquagen
production has been discontinued, but the identical allergen is now available as Timothy
Grass lyophilisate tablet, Grazax (ALK-Abello), an approved and licensed product for
treatment of severe seasonal allergic rhinitis. Grazax consists of purified, freeze-dried
Timothy Grass pollen extract, plus only three excipients, gelatin (from fish), mannitol and
sodium hydroxide. Preliminary investigations have shown that Grazax tablets can be dissolved
in saline to produce identical concentrations of allergen to Aquagen, with the same stability
profile in vitro. We anticipate therefore, that the clinical effect when used for nasal
allergen challenges would be equivalent to the use of Aquagen for a given allergen
concentration. In this study we intend to confirm that nasal symptoms produced during the NAC
with either Aquagen or Grazax will be equivalent. We will recruit volunteers with grass
pollen-induced hay fever to undergo NAC with each allergen source, sequentially. In an open,
randomised-order, cross-over study. The primary outcome will be patient-reported nasal
symptoms (according to a standardised scoring system) in the 60 minutes after each nasal
challenge.