Add-on histamine receptor-3 antagonist for allergic rhinitis: a double blind randomized crossover trial using the environmental exposure unit.
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ABSTRACT: BACKGROUND:Oral antihistamines that target the histamine receptor-1, such as fexofenadine, offer suboptimal relief of allergic rhinitis-associated nasal congestion. Combinations with oral sympathomimetics, such as pseudoephedrine, relieve congestion but produce side effects. Previous animal and human studies with histamine receptor-3 antagonists, such as PF-03654764, demonstrate promise. METHODS:Herein we employ the Environmental Exposure Unit (EEU) to conduct the first randomized controlled trial of PF-03654764 in allergic rhinitis. 64 participants were randomized in a double-blind, placebo-controlled 4-period crossover study. Participants were exposed to ragweed pollen for 6 hours post-dose in the EEU. The primary objective was to compare the effect of PF-03654764?+?fexofenadine to pseudoephedrine?+?fexofenadine on the subjective measures of congestion and Total Nasal Symptom Score (TNSS). The objectives of our post-hoc analyses were to compare all treatments to placebo and determine the onset of action (OA). This trial was registered at ClinicalTrials.gov (NCT01033396). RESULTS:PF-03654764?+?fexofenadine was not superior to pseudoephedrine?+?fexofenadine. In post-hoc analyses, PF-03654764?+?fexofenadine significantly reduced TNSS, relative to placebo, and OA was 60 minutes. Pseudoephedrine?+?fexofenadine significantly reduced congestion and TNSS, relative to placebo, with OA of 60 and 30 minutes, respectively. Although this study was not powered for a statistical analysis of safety, it was noted that all PF-03654764-treated groups experienced an elevated incidence of adverse events. CONCLUSIONS:PF-03654764?+?fexofenadine failed to provide superior relief of allergic rhinitis-associated nasal symptoms upon exposure to ragweed pollen compared to fexofenadine?+?pseudoephedrine. However, in post-hoc analyses, PF-03654764?+?fexofenadine improved TNSS compared to placebo. Side effects in the PF-03654764-treated groups were clinically significant compared to the controls.
SUBMITTER: North ML
PROVIDER: S-EPMC4094756 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
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