We hypothesized that the contrast agent iodixanol, as Nasapaque nasal solution, was effective in reducing nasal allergy symptoms.
This clinical trial enrolled 73 adult subjects with seasonal allergic rhinitis and positive ragweed skin tests. After priming at earlier visits, treatment efficacy (Nasapaque or placebo) was assessed at Visit 4 (90 minutes ragweed exposure in Ora’s Allergen BioCube® [ABC]) followed by treatment and additional 7.5 hours ABC exposure) and at Visit 5 (treatment 30 minutes before 3 hours ABC exposure). The primary efficacy endpoint was total nasal symptom score (TNSS, 0-12 scale) assessed at multiple time points pre- and during exposure. Mean TNSS differences between active and placebo treatment groups and change from baseline/pre-treatment differences were calculated (1-sided t-test, alpha = 0.10).
Subjects treated with Nasapaque (N = 36) had lower TNSS scores and greater change from baseline than placebo (N = 37) subjects. Onset of action for Nasapaque was as early as 15 minutes (mean Δ from baseline -3.2; treatment difference -0.9, 80% CI -1.6 to -0.2, p = 0.0602). Statistically significant differences were seen as late as 4.25 hours post-treatment (mean Δ from baseline -4.1; treatment difference -0.9, 80% CI -1.7, -0.1, p = 0.0754). Visit 4 3-hour post-treatment mean TNSS scores were 3.9 (Nasapaque) and 5.0 (placebo); -1.1 difference, 80% CI -2.0, -0.02, p = 0.0625. Visit 5 results also indicated greater efficacy with Nasapaque treatment, which was safe and well tolerated.
Nasapaque nasal solution is effective in reducing nasal allergy symptoms. Further evaluations of efficacy are warranted.