The purpose of this study is to determine the safety and effectiveness of tacrolimus inhalation aerosol in subjects with persistent asthma.

The purpose of this randomized, double-blind, placebo-controlled, parallel-group, multi-center designed trial is to determine the safety and efficacy of tacrolimus inhalation aerosol in subjects with persistent asthma.

Inclusion Criteria:

• Diagnosis of persistent asthma for at least 6 months
• Require use of beta-agonists at least four times per week

Exclusion Criteria:

• Diagnosis of chronic obstructive pulmonary disease (COPD)