The effectiveness of the ARIDOL Bronchial Challenge Test Kit in assessing bronchial hyperresponsiveness in adults and children 6 years of age and older was assessed in two clinical studies. Study 1 was an operator-blinded, open-label crossover trial that assessed the sensitivity and specificity of bronchial challenge testing with ARIDOL compared with a methacholine bronchial challenge test in detecting bronchial hyperresponsiveness in subjects with symptoms suggestive of asthma but without a definite diagnosis of asthma. During the course of the study subjects underwent three types of bronchial challenge tests utilizing exercise, ARIDOL, and methacholine. A positive exercise test was defined as a decrease in FEV1 ≥10%, a positive bronchial challenge test with ARIDOL was defined by either a decrease in FEV1 by ≥15% from baseline or a between-dose reduction in FEV1 ≥10%, and a positive methacholine response was defined as a decrease in FEV1 ≥20% after breathing methacholine at a concentration less than or equal to 16 mg/mL. The sensitivity and specificity of bronchial challenge testing with ARIDOL and methacholine were then assessed relative to exercise testing which served as a common comparator. The sensitivity and specificity of ARIDOL and methacholine challenges were also assessed using a blinded study physician's diagnosis of asthma at the end of the study. Five-hundred nine subjects aged 6 to 50 years were screened for enrolment with 419 and 420 subjects receiving at least one dose of mannitol, the active ingredient in ARIDOL, or methacholine, respectively. The maximum cumulative dose of mannitol was 635 mg. Bronchial challenge testing with ARIDOL and methacholine demonstrated similar sensitivity and specificity in predicting bronchial hyperresponsiveness defined by a positive exercise challenge (Table 4).

Bronchial challenge testing with ARIDOL and methacholine also demonstrated similar sensitivity and specificity when calculated relative to a blinded study physician's diagnosis of asthma in subjects at the end of the study.

The sensitivity and specificity of bronchial challenge testing with ARIDOL in children and adolescents 6 to 17 years of age in Study 1 was similar to that in the overall population (Table 4).

Study 2 was a crossover study comparing bronchial challenge testing with ARIDOL to hypertonic (4.5%) saline in identifying bronchial hyperresponsiveness in subjects 6 to 83 years of age with (n=551) and without (n=95) asthma. In this study the efficacy endpoint of interest was an estimation of the sensitivity and specificity of bronchial challenge testing with ARIDOL with respect to a physician's clinical diagnosis of asthma. Following completion of the bronchial challenge tests with ARIDOL and hypertonic saline, a respiratory physician assessed the data and categorized the subjects as having or not having asthma. The sensitivity of the ARIDOL bronchial challenge test in subjects with a physician diagnosis of asthma was 58% [(54%, 62%, 95th CI)] compared to a sensitivity of the physician diagnosis in the same population of 97% [(95%, 98%, 95th CI)]. The specificity of the ARIDOL bronchial challenge test in subjects without asthma was 95% [(90%, 99%, 95th CI)] compared to the specificity of the physician diagnosis of 98% [(95%, 100%, 95th CI)].