A Study to Compare the Efficacy of QAV680 Against Placebo in Treating Seasonal Allergic Rhinitis in an Environmental Exposure Chamber

Inclusion Criteria: * Positive skin prick test to ragweed allergen * FEV1 must be ≥80% predicted value at screening and prior to entry into EEC on Day -2. * Patients must weigh at least 50 kg, and must have a body mass index (BMI) within the range of 18 to 35 kg/m2. * Non-smokers and ex-smokers (≤10 pack years and \>6 months of smoking abstinence). * Understand and sign the written informed consent Exclusion Criteria: * Patients requiring a change in the use of any prescription drugs within four (4) weeks prior to initial dosing. * Participation in any clinical investigation within four (4) weeks prior to initial dosing or longer if required by local regulations, and for any other limitation of participation based on local regulations. * Significant illness within two (2) weeks prior to initial dosing. * History of immunodeficiency diseases, including a positive HIV (ELISA and Western blot) test result. * A positive Hepatitis B surface antigen (HBsAg) or Hepatitis C test result. Other protocol-defined inclusion/exclusion criteria may apply