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 two years after the start of treatment.

This is a follow-up study to a multi-centre, randomised, double-blind, placebo controlled, parallel group clinical study (TG002) which evaluated the efficacy, safety and tolerability of three doses of ToleroMune Grass versus placebo in grass allergic subjects. Subjects who completed TG002 in calendar year 2012 will undergo a further single exposure to grass allergens in an EEU.

Inclusion Criteria:

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

Exclusion Criteria:

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

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