Effectiveness of desloratadine 5 mg once daily in patients with symptoms of seasonal allergic rhinitis: Results of a Canadian multicenter, open-label trial

BACKGROUND: Seasonal allergic rhinitis (SAR) is an inflammatory response to seasonal allergens. Desloratadine, a once-daily selective histamine H(1)-receptor antagonist, has been reported to be efficacious in relieving symptoms of SAR in controlled clinical trials. However, to assess the actual effectiveness of a drug, it is important to examine information about its use in routine clinical practice. OBJECTIVE: The Partners in Allergy Control and Therapy (PACT) study examined the effectiveness of desloratadine in patients with SAR symptoms receiving treatment in a community setting of primary care physicians in Canada. METHODS: Patients with symptoms of SAR received desloratadine 5 mg once daily for 7 days during the spring-summer allergy season (April-July 2002). Patients rated their SAR symptoms along with their physicians by completing a questionnaire at baseline and day 7. Nasal, ocular, respiratory, and overall symptoms were rated on a scale of 0 (no symptoms evident) to 3 (severe/interfere with activities of daily living and/or sleeping). Physicians were asked to keep a record of adverse events reported by patients. The Wilcoxon signed-rank test was used to evaluate symptom severity scores. A 2-way (time x treatment), repeated measures, mixed analysis of variance (ANOVA) model was constructed to assess differences in variables over time. RESULTS: A total of 6829 patients participated in the study. Patients reported nasal stuffiness/congestion as their most severe symptom. Just over half (50.1%) of patients were receiving another medication for SAR at study entry; 29.7% were receiving an intranasal corticosteroid. After 7 days of treatment with desloratadine, individual symptom scores and overall symptom scores were significantly reduced compared with baseline (all scores, P<0.001). An improvement in nasal/stuffiness/ congestion was reported by 88.0% of patients. The ANOVA detected a statistically significant incremental benefit with desloratadine and an intranasal corticosteroid compared with desloratadine monotherapy (P<0.001). No severe adverse events were reported. CONCLUSION: Desloratadine 5 mg once daily was associated with significant improvement in symptoms of SAR, and appeared to provide additional benefit in relieving moderate to severe nasal stuffiness/congestion in 6786 patients receiving 7-day treatment in an actual practice setting of primary care physicians in Canada.