The purpose of this study is to find out how long the effect of PF-03526299 last after it is inhaled by assessing the lung function of mild asthma patients after they have been exposed to allergen

To assess duration of action of the compound in suppressing the early and late allergen response in asthma patients

Inclusion Criteria:

• Male and/or female subjects between the ages of 18 and 60 years, inclusive.
• A history or diagnosis of asthma that requires the use of beta 2 agonist bronchodilators (eg Salbutamol).
• Women who could become pregnant must use appropriate birth control throughout the study and pregnancy tests must be negative on entering the study and prior to dosing in the clinic.

Exclusion Criteria:

• Subjects who have been hospitalized for the treatment of asthma within three months prior to study entry, or have been hospitalized more than twice in last 12 months.
• Subjects who have experienced a lower respiratory tract infection (eg bronchitis or pneumonia) or significant asthma instability in the 4 weeks prior to study entry.
• Severe additional disease other than asthma