The aim of this study is to assess the effectiveness of a CRTH2 receptor antagonist, OC459, in preventing or attenuating the worsening of asthma symptoms during rhinovirus infection. The study is a double blind, randomised trial in which half the subjects will receive OC459 and the other half placebo, before being inoculated with rhinovirus, that would normally induce a worsening of asthma symptoms i.e. an exacerbation.
Asthma is the most common chronic respiratory disease, and in many countries prevalence is rising. The major morbidity, mortality and health care costs related to asthma are a result of periods of acutely increased symptomatology called 'exacerbations'. Most exacerbations are caused by rhinovirus, the virus associated with the common cold. There are few treatments to prevent and treat exacerbations, and despite these \>50% of adult asthmatics reported having an exacerbation in the last year. There is therefore a major unmet need. Experimentally inoculating patients with asthma with rhinovirus, a methodology that has been safely used for \>15 years, induces an infection and worsening symptoms in \~85%. This model offers the possibility to investigate treatment effects on asthma exacerbations with a small number of subjects, minimising the numbers exposed to a novel drug with limited safety data. In contrast, trials of therapies powered to evaluate an effect on naturally occurring exacerbations require several hundred subjects, a long study period to capture enough events, and are significantly more expensive to carry out. Using this model the investigators have shown that several inflammatory molecules, including prostaglandin D2 (PGD2), are significantly increased during rhinovirus-induced asthma exacerbations, with the levels of PGD2 strongly correlating with the severity of the symptoms. Moreover other studies have shown that when PGD2 binds the CRTH2 receptor, it stimulates the release of a number of inflammatory molecules also associated with asthma exacerbations. Blocking the CRTH2 receptor therefore appears an extremely promising target with potential to limit the virus-induced inflammation underpinning many asthma exacerbations.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
St Mary's Hospital
London, Greater London, United Kingdom
Total Lower Respiratory Symptom Score
Sum of daily scores for 14 days. Seven symptoms (cough on waking, wheeze on waking, daytime cough, daytime wheeze, daytime chest tightness, daytime breathlessness, nocturnal cough/wheeze/breathlessness) ranked from 0 (none) to 3 (severe). Range 0 to 294; higher is more symptomatic.
Time frame: During 14 days following rhinovirus inoculation
Change in Asthma Control Questionnaire (ACQ)-6 Score
Change from baseline (rhinovirus inoculation, day 0) to day 10. The ACQ was developed to measure the adequacy of asthma control in clinical research and in clinical practice. The ACQ-6 asks subjects to grade their asthma control, assessed through six questions, over the previous seven days. Each question is rated on a seven-point scale ranging from 0 (well controlled) to six (extremely poorly controlled). The ACQ-6 score is the mean of the scores on the 6 items. Mean scores of =\<0.75 indicate well-controlled asthma, scores between 0.76 and \< 1.5 indicate partly controlled asthma, and a score \>= 1.5 indicates uncontrolled asthma.
Time frame: Baseline, 10 days post rhinovirus inoculation
Percentage Change in Peak Expiratory Flow Rate
Percentage change from baseline (rhinovirus inoculation, day 0) to trough during infection (up to day 14)
Time frame: Baseline and up to 14 days post rhinovirus inoculation
Change in Forced Expiratory Volume in 1 Second (FEV1)
Percentage change from baseline (rhinovirus inoculation, day 0) to trough during infection (up to day 14)
Time frame: Baseline and up to 14 days post rhinovirus inoculation
Change in Exhaled Nitric Oxide (FeNO)
Percentage change from baseline (rhinovirus inoculation, day 0) to peak during infection (highest of measurements on days 3, 5, 7, 10 post inoculation)
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Masking
QUADRUPLE
Enrollment
44
Time frame: Baseline and up to 10 days post rhinovirus inoculation
Changes in Airway Hyper Responsiveness (Histamine)
Assessed as the provocation concentration of histamine producing a 20% fall in FEV1, or PC20 Change from baseline (rhinovirus inoculation, day 0) to day 7
Time frame: Baseline and 7 days post rhinovirus inoculation
Viral Load (in Nasal Lavage Samples)
Peak during infection (up to day 14)
Time frame: Up to 14 days post rhinovirus inoculation
Total Upper Respiratory Symptom Score
Sum of daily scores for 14 days. Eight upper respiratory symptoms (sneezing; runny nose; blocked or stuffy nose; sore throat or hoarse voice; headache or face pain; generally unwell; chill, fever or shivery; cough) ranked from 0 (none) to 3 (severe). Range 0 to 336; higher is more symptomatic.
Time frame: During 14 days following rhinovirus inoculation