The purpose of the study is to evaluate an investigational medication to treat chronic persistent asthma. The research is being conducted at up to 22 clinical research sites in the US and is open to both men and women ages 18 to 70 years old. Participants in the study will have a number of visits to a research site over a 10-month period. All study-related care and medication is provided to qualified participants at no cost: this includes all visits, examinations and laboratory work.

Inclusion Criteria:

• History of asthma for 6 or more months
• History of chronic persistent asthma requiring daily high dose inhaled corticosteroid for 3 or more months prior to enrollment

Exclusion Criteria:

• Patients with 10 or more pack years of smoking history or smoking within 12 months of study enrollment
• No significant disease other than asthma