Grass pollen allergens are recognised as a major cause of allergic diseases in humans and animals. Worldwide, at least 40% of allergic patients are sensitised to grass pollen allergens and between 50-90% of hayfever or seasonal allergy sufferers are allergic to grass pollen. ToleroMune Grass is a novel, synthetic, allergen-derived peptide desensitising vaccine, currently being developed for the treatment of grass allergy.

The purpose of this optional observational follow-on study is to further evaluate rhinoconjunctivitis symptoms on exposure to Grass in the EEU among subjects who completed all dosing visits in study TG002 approximately one year after the start of treatment.

Subjects who completed all dosing visits and the post treatment challenge (PTC) in study TG002 will be invited to attend the Screening Visit for TG002a. Subjects will attend for 4 visits to the EEU on successive days. Following the last EEC visit a follow-up visit will be performed 3-10 days later.

Inclusion Criteria:

• Previously randomised into study TG002, completed all treatment visits and PTC during calendar year 2012.

Exclusion Criteria:

• "Partly controlled" and "uncontrolled" asthma
• History of anaphylaxis to grass allergen
• FEV1 <80% of predicted.
• Treatment with beta-blockers, alpha-adrenoreceptor blockers, tranquilizers or psychoactive drugs
• Symptoms of a clinically relevant illness
• Subjects who cannot tolerate allergen challenge in the EEC

Subject previously randomised in study TG002 and completed all dosing visits and the PTC