To assess the reproducibility of the allergic response in the cat allergic subjects, measured as the change from baseline of the Total Nasal Symptom Score (TNSS) on the two challenge days.

To validate the Red Maple Trials Natural Exposure Chamber for cat exposure studies in non-asthmatic subjects with perennial allergic rhinitis and allergy to cat dander by examining the reproducibility of the response on two allergen challenge days and comparing the response of allergic to non-allergic subjects.

Inclusion Criteria for Allergic Subjects:

• Male and female adults, 18 years to 65 years of age
• Willing and able to give informed consent for participation in the study.
• Otherwise healthy with a diagnosis of perennial allergic rhinitis and a clinical history of nasal symptoms during exposure to cat in the previous 2 years
• With positive skin prick test reactivity to cat dander. A positive skin prick test is a wheal ≥3 mm larger than the negative control performed at the screening visit or within 6 months of the screening visit provided that complete documentation (specific allergen used for the SPT and the size of the reaction) is available
• Having sufficient rhinoconjunctivitis symptoms (TRCSS score ≥5) during the first cat challenge
• If subjects are taking medications (other than allergy medications), the dosing must be stable for at least 4 weeks prior to study entry
• With laboratory results at the screening visit which, in the opinion of the investigator, are clinically acceptable for the subject to be enrolled in the study
• Able (in the investigators opinion) and willing to comply with all study requirements

Exclusion Criteria for Allergic Subjects:

• Subjects with a cat at home or who are regularly exposed to cats during the study period

• Subjects with a diagnosis of asthma with the exception of mild intermittent asthma defined as normal lung function and intermittent treatment with a short-acting beta agonist only

• Subjects with a history of anaphylactic reactions defined as previous or current presentation with two or more of the following:

  • Involvement of the skin or mucosa
  • respiratory difficulties
  • low blood pressure
  • gastrointestinal symptoms

• Subjects who have undergone allergen desensitization for cat allergy within the last 2 years

• Subjects with structural nasal defects or nasal polyps

• Subjects with a positive skin-prick test reaction to house dust mite

• Subjects having an infection of the upper airways within 2 weeks prior to the screening visit.

• Subjects who develop an upper respiratory tract infection during the study will be discontinued

• Subjects who have received treatment with Xolair or immunosuppressants during the 4 months prior to the screening visit

• Subjects who wear contact lenses will not be permitted to wear them during the challenge sessions

• Female subjects who are pregnant or lactating at screening or who are planning pregnancy during the course of the study

• Subjects with significant renal or hepatic impairment at screening

• Subjects with scheduled elective surgery or other procedures requiring general anaesthesia during the study

• Subjects with any other significant disease or disorder which, in the opinion of the investigator, may either put the participant at risk because of participation in the study, or may influence the outcomes of the study, or the participant's ability to participate in the study

• Subjects who have participated in another research study involving an investigational product within 30 days or 5 half-lives prior to the screening visit

• Subjects who are using unacceptable concomitant medications within the washout period prior to the screening visit (see Table 7.2-1)

• Subjects with a history of alcohol or drug abuse within the previous 5 years

• Subjects with known HIV or hepatitis B or C positivity

• Subjects who for any reason would be unlikely to comply with the study requirements

Inclusion Criteria for non allergic subjects:

• Healthy male and female adults, 18 years to 65 years of age
• Willing and able to give informed consent for participation in the study.
• With laboratory results at the screening visit which, in the opinion of the investigator, are clinically acceptable for the subject to be enrolled in the study
• Able (in the investigators opinion) and willing to comply with all study requirements

Exclusion Criteria for non allergic subjects:

• With a diagnosis of perennial allergic rhinitis and a clinical history of nasal symptoms during exposure to cat in the previous 2 years

• With positive skin prick test reactivity to cat dander. A positive skin prick test is a wheal ≥3 mm larger than the negative control performed at the screening visit

• Subjects with a cat at home or who are regularly exposed to cats during the study period

• Subjects with a diagnosis of asthma with the exception of mild intermittent asthma defined as normal lung function and intermittent treatment with a short-acting beta agonist only

• Subjects with a history of anaphylactic reactions defined as previous or current presentation with two or more of the following:

  • Involvement of the skin or mucosa
  • respiratory difficulties
  • low blood pressure
  • gastrointestinal symptoms

• Subjects with structural nasal defects or nasal polyps

• Subjects with a positive skin-prick test reaction to house dust mite

• Subjects having an infection of the upper airways within 2 weeks prior to the screening visit.

• Subjects who develop an upper respiratory tract infection during the study will be discontinued

• Subjects who have received treatment with Xolair or immunosuppressants during the 4 months prior to the screening visit

• Subjects who wear contact lenses will not be permitted to wear them during the challenge sessions

• Female subjects who are pregnant or lactating at screening or who are planning pregnancy during the course of the study

• Subjects with significant renal or hepatic impairment at screening

• Subjects with scheduled elective surgery or other procedures requiring general anaesthesia during the study

• Subjects with any other significant disease or disorder which, in the opinion of the investigator, may either put the participant at risk because of participation in the study, or may influence the outcomes of the study, or the participant's ability to participate in the study

• Subjects who have participated in another research study involving an investigational product within 30 days or 5 half-lives prior to the screening visit

• Subjects who are using unacceptable concomitant medications within the washout period prior to the screening visit (see Table 7.2-1)

• Subjects with a history of alcohol or drug abuse within the previous 5 years

• Subjects with known HIV or hepatitis B or C positivity

• Subjects who for any reason would be unlikely to comply with the study requirements