Efficacy & Safety of Symbicort® TURBUHALER® 160/4.5 µg Twice Daily & Pulmicort® TURBUHALER® 200 µg Twice Daily + Theolong® Tablet 200 mg Twice Daily in Japanese Asthmatic Patients

Inclusion Criteria: * Diagnosis of asthma with a documented history of at least 6 months duration prior to Visit 1 * Prescribed daily use of an IGCS for \>=12 weeks prior to Visit 1. The dose of IGCS must be 400 to 800 µg/day of Pulmicort® Turbuhaler® or corresponding dose of IGCS. The prescribed dose of IGCS should be constant for at least 4 weeks prior to Visit 1 * Prescribed daily use of sustained release theophylline for at least 8 weeks prior to Visit 1, or confirmed steady-state blood theophylline concentrations within the effective range (5-15 µg/mL) during 8 weeks prior to Visit 1. The prescribed dose of theophylline should be constant (400 mg/day) for at least 4 weeks prior to Visit 1 Exclusion Criteria: * Any significant disease or disorder that may jeopardize the safety of the patient * Respiratory infection, judged by the investigator(s) as an infection affecting the asthma, within 4 weeks prior to Visit 1 * Treatment with oral, parenteral or rectal GCS within 4 weeks prior to Visit 1 Additional inclusion and exclusion criteria will be evaluated by the Investigator