Evaluation of Various Doses of Ro 27-2771 (Test Drug) in Asthmatic Patients Not Treated With Inhaled Corticosteroids

Inclusion Criteria: * Persistent asthma for more than one year * Current treatment for asthma with short acting inhaled beta 2 agonists (such as albuterol) only * In good health ad demonstrated by medical history and physical exam * Negative urine pregnancy test * Commitment to use two forms of effective contraception simultaneously throughout the study duration and for one month after discontinuing therapy Exclusion Criteria: * Asthma necessitating treatment with inhaled corticosteroids for at least one month before the start of the study * History of severe asthma necessitating the use of oral/injectable corticosteroids within the last 2 months and/and or two bursts in the last year * Undergoing allergy shots unless on a stable maintenance dose for three months before the start of the study * History of chronic pulmonary diseases other than asthma * Treatment of conditions other than asthma with oral corticosteroids within one month of the start of the study * Current tobacco use * Smoking history of greater than 10 pack-year history of cigarette smoking (number of packs smoked per day times the number of years smoked) * History or evidence of drug or alcohol abuse * Diagnosis or evidence of an infectious illness within one month of Visit 1 * Clinically significant diseases as assessed by the study doctor * Participation in another clinical study with an experimental drug within one month of start of the study