Adults and Adolescents 12 Years of Age and Older

The efficacy of levocetirizine dihydrochloride was evaluated in four randomized, placebo-controlled, double-blind clinical trials in adult and adolescent patients 12 years and older with symptoms of perennial allergic rhinitis. The four clinical trials include two dose-ranging trials of 4 weeks duration and two efficacy trials (one 6-week and one 6-month) in patients with perennial allergic rhinitis.

These trials included a total of 1729 patients (752 males and 977 females) of whom 227 were adolescents 12 to 17 years of age. Efficacy was assessed using a total symptom score from patient recording of 4 symptoms (sneezing, rhinorrhea, nasal pruritus, and ocular pruritus) in three studies and 5 symptoms (sneezing, rhinorrhea, nasal pruritus, ocular pruritus, and nasal congestion) in one study. Patients recorded symptoms using a 0 to 3 categorical severity scale (0 = absent, 1 = mild, 2 = moderate, 3 = severe) once daily in the evening reflective of the 24 hour treatment period. The primary endpoint was the mean total symptom score averaged over the first week and over 4 weeks for perennial allergic rhinitis trials.

The two dose-ranging trials were conducted to evaluate the efficacy of levocetirizine dihydrochloride 2.5, 5, and 10 mg once daily in the evening. These trials were 4 weeks in duration and included patients with perennial allergic rhinitis. In these trials, each of the three doses of levocetirizine dihydrochloride demonstrated greater decrease in the reflective total symptom score than placebo and the difference was statistically significant for all three doses in the two studies. Results for one of these trials are shown in Table 4.

One clinical trial evaluated the efficacy of levocetirizine dihydrochloride 5 mg once daily in the evening compared to placebo in patients with perennial allergic rhinitis over a 6-week treatment period. Another trial conducted over a 6-month treatment period assessed efficacy at 4 weeks. Levocetirizine dihydrochloride 5 mg demonstrated a greater decrease from baseline in the reflective total symptom score than placebo and the difference from placebo was statistically significant. Results of the former are shown in Table 5.

Onset of action was evaluated in two environmental exposure unit studies in allergic rhinitis patients with a single dose of levocetirizine dihydrochloride 2.5 or 5 mg. Levocetirizine dihydrochloride 5 mg was found to have an onset of action 1 hour after oral intake. Onset of action was also assessed from the daily recording of symptoms in the evening before dosing in the allergic rhinitis trials. In these trials, onset of effect was seen after 1 day of dosing.

Pediatric Patients Less than 12 Years of Age

There are no clinical efficacy trials with levocetirizine dihydrochloride 2.5 mg once daily in pediatric patients under 12 years of age, and no clinical efficacy trials with levocetirizine dihydrochloride 1.25 mg once daily in pediatric patients 6 months to 5 years of age. The clinical efficacy of levocetirizine dihydrochloride in pediatric patients under 12 years of age has been extrapolated from adult clinical efficacy trials based on pharmacokinetic comparisons [see Use in Specific Populations (8.4)].