Effect of olopatadine-mometasone combination nasal spray on seasonal allergic rhinitis symptoms in an environmental exposure chamber study

Background: GSP301 nasal spray is a fixed-dose combination of the antihistamine olopatadine hydrochloride and the corticosteroid mometasone furoate intended for seasonal allergic rhinitis (SAR) treatment.

Objective: To evaluate the efficacy and safety of once-daily or twice-daily GSP301 in a ragweed pollen environmental exposure chamber.

Methods: In this randomized, double-blind, double-dummy study, adults (18-65 years old) with SAR were equally randomized to 665 μg of olopatadine and 25 μg of mometasone (twice-daily GSP301), 665 μg of olopatadine and 50 μg of mometasone (once-daily GSP301), a US Food and Drug Administration-approved formulation of 137 μg of azelastine and 50 μg of fluticasone twice-daily (AzeFlu), a US Food and Drug Administration-approved formulation of 665 μg of olopatadine twice-daily, or placebo (twice-daily). During 2 visits (baseline and end of 14-day treatment), participants assessed SAR symptoms at specified time points. The primary end point-mean change from baseline in instantaneous total nasal symptom score (iTNSS) for twice-daily or once-daily GSP301 vs placebo-was analyzed by analysis of covariance. Onset of action, ocular symptoms, and adverse events were assessed.

Results: A total of 180 participants were randomized. Treatment with twice-daily or once-daily GSP301 provided statistically significant improvements in iTNSS vs placebo (twice-daily GSP301: least squares mean difference, -3.60; 95% confidence interval [CI], -4.89 to -2.30; once-daily GSP301: least squares mean difference, -3.05; 95% CI, -4.35 to -1.76; P < .0001 for both). Significant improvements in iTNSS with twice-daily GSP301 occurred by 10 minutes after dosing (-1.26; 95% CI, -2.30 to -0.21; P = .02) and were maintained at all later time points except one (2.5 hours). Treatment-emergent adverse events occurred in 22.2%, 30.6%, 25.0%, 22.2%, and 16.7% of participants in the twice-daily GSP301, once-daily GSP301, AzeFlu, olopatadine, and placebo groups, respectively.

Conclusion: In an environmental exposure chamber model, twice-daily and once-daily GSP301 treatments were well tolerated and provided statistically significant and clinically meaningful SAR symptom improvement vs placebo.

Trial registration: ClinicalTrials.gov Identifier: NCT03444506.