Results from the international, multicenter Child Hood Asthma Safety and Efficacy (CHASE) 3 Phase III study showed that SYMBICORT ® (budesonide/formoterol fumarate dihydrate) Inhalation Aerosol 80/4.5 micrograms significantly improved lung function in pediatric patients between 6 to <12 years of age with asthma versus budesonide 80 micrograms, demonstrating its appropriateness as step-up therapy in this patient population. The CHASE 3 Phase III study evaluated the efficacy and safety of budesonide/formoterol in a pressurized metered dose inhaler (pMDI) 80/2.25 micrograms, and SYMBICORT pMDI 80/4.5 micrograms, compared with budesonide pMDI 80 micrograms in children with asthma, ages 6 to <12 years, who were given two inhalations twice a day for 12 weeks. The children had previously received either medium-dose inhaled corticosteroid (ICS) or ICS/ long-acting beta 2-adrenergic agonists (LABA). The primary efficacy endpoint was change from baseline pre-dose (randomization) to 1-hour post-dose forced expiratory volume in one second (FEV 1) at week 12. AstraZeneca conducted the CHASE 3 study after the US Food and Drug Administration (FDA) requested additional data on budesonide and formoterol, specifically regarding the impact of different doses, in pediatric asthma patients between 6 to <12 years of age. The study results showed changes from baseline at week 12 in 1-hour post-dose FEV 1 and 15-minute post-dose FEV 1 were significantly greater with SYMBICORT 80/4.5 micrograms two inhalations twice daily versus budesonide 80 micrograms two inhalations twice daily (both p=0.015), but not budesonide/formoterol 80/2.25 micrograms two inhalations twice daily versus budesonide 80 micrograms two inhalations twice daily. The change from baseline in 1-hour post-dose PEF (peak expiratory flow) was superior at week 12 with SYMBICORT 80/4.5 micrograms versus other treatments (p<0.05). There were no notable differences in safety profiles between either of the budesonide/formoterol doses and budesonide or between the two budesonide/formoterol doses. Among the most common adverse events, upper respiratory tract infection, pharyngitis, headache, and vomiting were more frequent, with budesonide/formoterol doses compared to the budesonide 80 micrograms dose.