Compare the Efficacy of Levocetirizine and Montelukast to Placebo in Reducing Seasonal Allergic Rhinitis (SAR) Symptoms in Ragweed Sensitive Subjects

Double-blind, Three Parallel Randomized Groups, Therapeutic Confirmatory Clinical Trial to Compare the Efficacy of Oral Levocetirizine 5 mg and Montelukast 10 mg to Placebo in Reducing Symptoms of Seasonal Allergic Rhinitis (SAR) in Ragweed Sensitive Subjects Exposed to Ragweed Pollen in an Environmental Exposure Unit (EEU)

To compare the clinical efficacy of levocetirizine 5 mg and montelukast 10 mg on symptoms of seasonal allergic rhinitis occurring in subjects exposed to ragweed pollen in an environmental exposure unit.

Inclusion Criteria:

• Have had seasonal allergic rhinitis due to Ragweed for the last 2 consecutive years
• Subjects who obtain a minimum sum score, considering Seasonal Allergic Rhinitis (SAR) related symptoms (mean value), as defined by the protocol

Exclusion Criteria:

• Any clinically significant condition that might interfere with the treatment evaluation, both for efficacy and safety
• Have used forbidden concomitant medications as defined by the protocol