A Blinded Study To Examine The Ability Of PF-610,355 To Open The Airways In Asthmatic Patients.

A Phase IIA Randomised, Double-blind, Double Dummy, Placebo and Active Controlled 5-Way Cross-over Trial to Examine the Bronchodilator Effects of PF-610,355 and to Test for Superiority Versus Placebo in Reversible Asthmatic Patients

A study to determine the ability of different doses of PF-610,355 to open the airways in asthmatic patients by comparison with placebo and a marketed drug that also opens the airways in asthmatic patients.

Inclusion Criteria:

• Reversible asthmatic patients (>15% increase in FEV1 following 200ug salbutamol).
• FEV1 greater than or equal to 60% predicted
• Stable disease for at least the previous 3 months

Exclusion Criteria:

• Subjects requiring rescue medication on greater than 2 occasions in the 72 hours prior to screening
• Subjects with a history of pulmonary disease other than asthma.