Ragweed is the primary cause of autumn allergies. The ragweed season begins in mid-August. In the third National Health and Nutrition Examination Surveys54.3% of the population had positive test responses to one or more allergens, with the prevalence for short ragweed being 26.2%

The purpose of this observational follow-on study is to further evaluate rhinoconjunctivitis symptoms on exposure to ragweed allergen in the EEC among subjects who completed all dosing visits and the post treatment challenge (PTC) visit in study TR002 approximately one year after the start of treatment.

Subjects who were randomised in study TR002 and who completed all dosing visits and the PTC will be invited to attend the Screening Visit for TR002B. Subjects will attend the EEC for 4 visits on successive days. Following the final EEC visit a follow-up visit will be performed 3-10 days later.

Inclusion Criteria

• Previously randomised into study TR002 and completed all treatment visits and the PTC.

Exclusion Criteria

• History of asthma (a diagnosis of asthma in childhood may be allowed).
• Subjects with an FEV1 <70% of predicted.
• Subjects being treated with beta-blockers.
• Developed a significant disease, disorder or inability to communicate, since completing study TR002 which, in the opinion of the Sponsor's medical representative, may either put the subject at risk because of participation in the study, or influence the results of the study, or the subject's ability to participate in the study.

Subjects previously randomised in study TR002 and completed all dosing visits and the Post Treatment Challenge (PTC).