RV568 is being developed for the treatment of diseases such as asthma, COPD and allergic rhinitis (e.g. hayfever). The main aim of this study is to investigate whether RV568 ameliorates the nasal symptoms to low doses of grass pollen in healthy subjects with seasonal allergic rhinitis.

Inclusion Criteria:

• Subject is healthy
• History of seasonal allergic rhinitis
• Male aged between 18 and 55 years
• Body weight >/= 50 kg with BMI in range 19 - 29 kg/m2 (inclusive)
• Exhibits a moderate response to 4 hour exposure to grass pollen in the challenge chamber with a total nasal symptom score (TNSS) of >/= 6
• Positive skin prick test (wheal >/= 4 mm) for grass pollen
• Positive total IgE result (RAST class >/= 2) for grass pollen
• Current non-smoker who has not used tobacco in the past 6 months with a pack history of </= 10 pack years
• Baseline FEV1 >/= 80% and FEV1/FVC >/= 70% of predicted values
• No conditions or factors that may preclude subjects ability to remain in the challenge chamber for a period of 6 hours
• capable of giving informed consent and is compliant with protocol requirements
• available to complete all study measurements

Exclusion Criteria:

• structural nasal abnormalities or nasal polyps, history of frequent nosebleeds, recent nasal surgery or recent (within 3 weeks) or ongoing upper respiratory tract infection
• history of drug allergy
• participation in another clinical trial or has participated in a study using an NCE within the previous 3 months, or any clinical study within 1 month
• taking regular (or a course of) medication whether prescribed or not, including steroids, vitamins, macrolides, anti-fungal agents and herbal remedies. Paracetamol (</= 2g / day) and occasional short acting beta agonists are permitted
• use of oral, injectable or dermal steroids within 5 weeks or intranasal and/or inhaled steroids within 1 week of the screening visit
• past or present disease, which as judged by the investigator, may affect the outcome of the study
• regular consumption of > 21 units alcohol per week
• infected with Hepatitis B, Hepatitis C, or HIV virus
• current or chronic history of liver disease, or known hepatic or biliary abnormalities
• positive test for drugs of abuse or alcohol at screening
• previously known allergy to any of the active or inactive ingredients in the study medication
• mentally or legally incapacitated
• any other reason that the investigator considers makes the subject unsuitable to participate