• Weighted Mean Change From Baseline Over 0-6 Hours in Blood Eosinophils Post Allergen Challenge on Day 14 [ Time Frame: 0-6 hours, post allergen challenge, 1 hour post treatment, Day 14 ] [ Designated as safety issue: No ]
• Weighted Mean Change From Baseline Over 0-6 Hours in Serum IL-5 Post Allergen Challenge on Day 35 [ Time Frame: 0-6 hours post allergen challenge, 10-11 hours post treatment, Day 35 ] [ Designated as safety issue: No ]
• Weighted Mean Change From Baseline Over 0-6 Hours in Serum IL-5 on Day 14 [ Time Frame: 0-6 hours post allergen challenge, 1 hour after dosing, Day 14 ] [ Designated as safety issue: No ]

The aim of the present study is to investigate whether the effects of salmeterol in combination with fluticasone propionate on blood markers of airway inflammation are maintained after chronic dosing and whether the effect is influenced by the time of allergen challenge relative to the time of dosing.

A 19-week, randomized, double-blind, placebo-controlled, three-period, cross-over pilot study comparing the effect of salmeterol/fluticasone propionate 50/100mcg BID, fluticasone propionate 100mcg BID and placebo on blood markers of airway inflammation in response to allergen challenge in asthma subjects

Inclusion Criteria:

• Informed consent.
• Outpatient.
• Male or non-pregnant/non-lactating female.
• Aged 18-55.
• Diagnosis of asthma.
• Pre-bronchodilatory FEV1 > 75% predicted.
• Using inhaled short-acting beta-2-agonists (SABA) with no inhaled corticosteroids.
• Judged capable of withholding SABA for at least 6 hours prior to visits.
• Reversibility of >12% and 200mL or PC20 of <8mg/mL.
• Demonstration of atopy

Exclusion Criteria:

• History of life-threatening asthma.
• Use of proscribed asthma medications.
• Use of anti-histamines or potent inhibitors of CYP3A4.
• Respiratory tract infection.
• Asthma exacerbation with 4 weeks of Visit 1.
• Subjects with exercise induced asthma only.
• Concurrent respiratory disease.
• Other clinically significant, uncontrolled condition or disease.
• Use of any investigational drug within 30 days.
• Allergic to beta-2-agonists, inhaled corticosteroids or excipients.
• Positive pregnancy test.
• Using immunosuppressive medications.
• Milk protein allergy.
• Factors likely to interfere with attendance.
• Current smokers or ex-smokers with a history of >10 pack years.
• Affiliation wih Investigator site.
• Medications that may affect the course of asthma or interact with sympathomimetic amines.