Efficacy and safety of bilastine 20 mg compared with cetirizine 10 mg and placebo in the treatment of perennial allergic rhinitis

Objective: Bilastine is a non-sedating second-generation H-1 antihistamine with proven efficacy and safety in the treatment of patients with seasonal allergic rhinitis and urticaria. The objective of this study was to demonstrate the efficacy and safety of bilastine in patients with perennial allergic rhinitis (PAR). Methods: In a multicenter, randomized, placebo-controlled, double-blind, parallel-group study, patients with symptomatic PAR (n = 650) from Argentina, Europe, and South Africa received bilastine 20 mg, cetirizine 10 mg, or placebo once daily for 4 weeks. The primary efficacy outcome was the mean area under the curve (AUC) of reflective total 6-symptom scores (rT6SS) from baseline visit to day 28 (D28). Secondary outcome measures included mean AUC of instantaneous total 6-symptom scores (iT6SS), and mean AUCs of reflective and instantaneous total 4-nasal symptom scores (T4NSS) and total 2-ocular symptom scores (T2OSS) from baseline to D28. An open-label extension phase evaluated the safety of bilastine 20 mg administered to patients (n = 513) for one year. Results: In the overall population no significant differences in efficacy outcomes were found between active treatments and placebo. On account of the high placebo response in South Africa, a post-hoc analysis was conducted. This analysis demonstrated that statistically significant differences existed between active treatments and placebo in the mean AUC of rT6SS (p<0.05) and T4NSS (p<0.02), respectively, from baseline to D28 visit for the intent-to-treat population in patients from Europe and Argentina, whereas the difference was not statistically significant in South Africa. Whether this is related to differences in the demographic or clinical characteristics of South African patients (they had PAR for longer and reported more severe symptoms) and/or the disease management process compared with their European and Argentinean counterparts warrants further investigation. Conclusions: A post-hoc analysis indicated that bilastine and cetirizine were similarly effective and more effective than placebo during a 4-week treatment period in patients with PAR. In addition, bilastine was shown to be safe and well-tolerated over a 1-year treatment period.