Evaluation of Montelukast for the Treatment of Children With Japanese Cedar Pollinosis Using an Artificial Exposure Chamber (OHIO Chamber).

Background: This study evaluated the efficacy of montelukast in reducing seasonal allergic rhinitis symptoms in Japanese children with Japanese cedar (JC) pollinosis induced in an artificial exposure chamber (OHIO Chamber).

Methods: Pediatric patients aged 10 to 15 years sensitive to JC pollen entered a randomized, double-blind, single-site, crossover study. After confirmation of an allergic response to a JC pollen exposure for 3 hours in the OHIO Chamber during the screening period, subjects received either montelukast 5 mg chewable tablets or placebo for a 7-day treatment period, followed by a 3-hour pollen exposure in the chamber. After a 7-day washout period, subjects crossed over to the other treatment. Subjects were instructed to self-assess their nasal symptoms using 5-point scale for every 30 minutes. The primary end point was the change from baseline (just before entering the exposure chamber for each exposure) in total nasal symptom score (TNSS; the sum of nasal congestion, nasal discharge, and sneezing scores) over 3 hours of pollen exposure. Adverse events (AEs) were evaluated throughout the study.

Results: A total of 220 subjects (median age, 12 years) received treatment. For TNSS, the between-group difference in the change (95% confidence interval) was -0.01 (-0.11 to 0.10); the change between placebo and montelukast 5 mg was not significant. TNSS in the screening and treatment periods after receiving placebo for 7 days was 1.58 and 1.31, respectively, suggesting a placebo response. On account of high placebo response, a post hoc analysis was conducted. The analysis in a subgroup of subjects who did not show placebo response demonstrated a difference in the efficacy between montelukast and placebo (nominal P  < .037). The most common AE was positive urine protein (4.6% with montelukast vs 7.8% with placebo).

Conclusions: Although montelukast was well tolerated, this study did not demonstrate a treatment difference between active drug and placebo in Japanese children exposed to JC pollen in the OHIO Chamber. Trial Registry : ClinicalTrials.gov, NCT01852812.