A Study of Omalizumab in the Prevention of Allergen Induced Airway Obstruction in Adults With Mild Allergic Asthma

Inclusion Criteria: * Signed Informed Consent Form * Meet criteria for the diagnosis of allergic asthma * Be between the ages of 18 to 65 years * Have a normal chest X-ray within 2 years of screening Exclusion Criteria: * Need daily controller medication for asthma * History of hypersensitivity to the study drug or to drugs with similar chemical structures or to any ingredients, including excipients of the study medication or drugs related to omalizumab (e.g., monoclonal antibodies, polyclonal gamma globulin) * Have a documented medical history of anaphylaxis * Have lung disease other than mild allergic asthma * Have taken other investigational drugs within 30 days or 5 half-lives prior to the screening visit, whichever is longer * Are unable or unwilling to comply with study procedures and visits * Are pregnant or lactating * Have significant medical illness other than asthma, including malignancies, parasitic infections, immune system disorders, and thrombocytopenia * Have been treated with omalizumab within 12 months prior to screening * Currently smoke or have a history of smoking more than 10 pack-years * Have a history of drug or alcohol abuse, which, in the judgment of the investigator, may put the subject at risk for being unable to participate fully in the study for the duration of the study