This study will assess the safety and efficacy of QAW039 alone and in combination with Montelukast in patients with allergic rhinitis (hay fever) using an environmental exposure chamber.

Inclusion Criteria:

• Male or female aged 18-65 years inclusive, with a clinical history of intermittent allergic rhinitis with seasonal onset and offset of nasal allergy symptoms during each of the last two grass pollen allergy seasons.
• A positive skin prick test at Visit 1 to dactylis glomerata with a wheal diameter equal to or greater than 3 mm and a negative control with a wheal diameter of zero. A positive skin prick test within 12 months prior to Visit 1 is also acceptable.
• FEV1 measured by spirometry must be ≥80% of their predicted value at screening. If the patient does not achieve ≥80% of their predicted value this may be repeated prior to the EEC challenge at visit 2.
• TNSS score ≥6 on at least one assessment during the 2h EEC challenge at Screening.

Exclusion Criteria:

• Use of other investigational drugs at the time of enrollment, or within 30 days or 5 half-lives of enrollment, whichever is longer; or longer if required by local regulations, and for any other limitation of participation in an investigational trial based on local regulations.
• Pregnant or nursing (lactating) women,
• Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, unless they are using effective methods of contraception during dosing of study treatment.