Improving SAR symptoms with levocetirizine: evaluating active and placebo effects in pollen challenge vs. natural exposure studies

Abstract

Objective:

Despite a plethora of published data on levocetirizine, no meta-analyses exist on the effect of study design, and covariates like age, gender, and baseline symptom severity on treatment response. The objective of this study was the efficacy of levocetirizine 5 mg tablets and matching placebo at reducing allergy symptoms in adult subjects with seasonal allergic rhinitis under various pollen exposure study conditions and by age, gender and baseline symptom severity.

Methods:

This was a meta-analysis of original reports from randomized, double-blind, placebo-controlled studies. Clinical studies without detailed reports, open-label, non-randomized and non-controlled studies, or paediatric studies, were excluded. Study subjects were divided into an environmental exposure (EE) group or a natural exposure (NE) group.

Results:

Data from 3640 subjects were analysed (n = 2174 for levocetirizine, n = 1466 for placebo). The overall results confirmed the efficacy of levocetirizine 5 mg, with an approximately 40% symptom score improvement from baseline, in both the EE and NE groups. While levocetirizine showed no gender- or age-related differences in efficacy, female subjects responded better to placebo in the EE, but not in the NE group; younger subjects (<30 years of age) responded less favourably to placebo compared with older subjects (≥50 years of age). Levocetirizine was consistently superior to placebo regardless of baseline symptom score levels. The highest significance levels between the active and placebo groups were observed in subjects sensitized to animal dander and grass.

Conclusions:

Differences between an oral antihistamine and placebo in clinical studies of allergic rhinitis might be due to a different response to placebo rather than to the active drug. Levocetirizine seems to have consistent efficacy regardless of age, gender, and baseline scores.

Key words::

• Consistent efficacy
• Levocetirizine
• Meta-analysis
• Responder
• Seasonal allergic rhinitis
• Sub-group

Transparency

Declaration of funding

The presented meta-analysis and the writing of this manuscript were funded solely by UCB Inc., USA and sanofi-aventis USA.

Declaration of financial/other relationships

All authors have disclosed that they are employees of the companies producing or marketing levocetirizine.

Some peer reviewers receive honoraria from CMRO for their review work. The peer reviewers of this paper have disclosed that they have no relevant financial relationships.

Acknowledgements

The authors have disclosed that they had no outside editorial assistance in preparing this manuscript.