D2.238 - Bilastine fast onset and strong peripheral antihistaminic activity: comparison with oral second-generation antihistamines and intramuscular dexchlorpheniramine in histamine-induced wheal and flare models

When treating allergies with antihistamines (AH), beyond overall efficacy, a fast onset of action and strong antihistamine peripheral activity are essential to achieve early symptom control and quality of life improvement. The histamine-induced wheal & flare (W&F) model is a validated pharmacodynamic (PD) method to assess peripheral antihistaminic activity. Bilastine, a second-generation AH with minimal brain penetration, has been evaluated in several clinical trials using comparable W&F methodologies, allowing an integrated assessment of its onset and magnitude of effect relative to other AHs. The objective of this study is to evaluate onset, magnitude and duration of W&F inhibition and itching reduction with bilastine 20 mg as compared with other AHs pooling PD data from controlled clinical trials.

Data from W&F randomized clinical trials evaluating bilastine (using either skin prick test or intradermal histamine injection) were included. Comparators included cetirizine, desloratadine, rupatadine, and intramuscular dexchlorpheniramine. W&F area and itching perception reduction were analysed over time to evaluate onset and extent of peripheral antihistaminic activity.

Across studies, oral bilastine 20 mg showed a consistently fast onset of action, with a statistically significant W&F versus placebo inhibition as early as 15-30 minutes post-dose and high levels of inhibition during the first hours. Bilastine showed greater early inhibition than standard dose cetirizine, desloratadine, and rupatadine, with sustained significant efficacy up to 24 hours. Bilastine also provided an earlier and higher reduction in itching perception, a consistent significant effect observed with bilastine but not with several comparators. Reduced plasma exposure of bilastine under fed conditions did not result in clinically relevant loss of efficacy and itching suppression. Notably, 20 mg oral bilastine showed a stronger peripheral H1 blockade than intramuscular dexchlorpheniramine without inducing sedation nor psychomotor or driving impairment.

Across controlled PD studies, bilastine consistently demonstrates a fast onset of action, a strong and sustained antihistaminic activity, and an early itching relief, with a favourable safety profile and preserved efficacy under fed conditions. These findings support the first-line use of bilastine as a fast-acting and efficient antihistamine for the management of allergic diseases requiring rapid symptom control.