Methods	Parallel-group, multicentre study (151 centres in USA). Five treatment arms of which 2 are considered here
Participants	% ELIGIBLE OF SCREENED POPULATION: 28 % RUN-IN PARTICIPANTS RANDOMISED: 63 RANDOMISED: 297 (BUD/F 200 qd: 152; BUD 400 qd: 145) WITHDRAWALS: BUD/F 200 qd: 19;BUD/F 400 qd: 28 AGE mean: 38 SEVERITY: Not reported BASELINE % PREDICTED FEV1: 75.3% BASELINE DOSE OF ICS: 382 ASTHMA DURATION: 19.7 ATOPY (%): Not reported ELIGIBILITY CRITERIA: > 16 years; documented clinical diagnosis of asthma for at least 6 months prior to screening; stable condition; maintenance asthma treatment with a low to medium dose ICS for at least 4 weeks prior to the screening; FEV1 60% to 90% predicted EXCLUSION CRITERIA: Not reported ELIGIBILITY CRITERIA DURING RUN-IN: Stable during run-in period
Interventions	OUTCOMES: 12 weeks RUN-IN PERIOD: 4 to 5 weeks DOSE OPTIMISATION PERIOD: None INTERVENTION PERIOD: 12 weeks TEST GROUP: Combination budesonide and formoterol (200/12 mcg) qd CONTROL GROUP: Budesonide 400 mcg qd NUMBER OF DEVICES: 2 (double-dummy design; LABA co-delivered with ICS in 1 inhaler) COMPLIANCE: Not assessed CO-TREATMENT prn SABA
Outcomes	PULMONARY FUNCTION TEST: am PEF; pm PEF; FEV1 SYMPTOM SCORES: Day symptoms; night symptoms FUNCTIONAL STATUS: Quality of life (AQLQ) INFLAMMATORY MARKERS: Not reported ADVERSE EFFECTS: Reported WITHDRAWALS: Reported
Notes	Unpublished trial data from www.astrazenecaclinicaltrials.com Funding source: AZ Confirmation of data and methodology: Not obtained User defined number: 400
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	Unclear	Described as randomised; other information not available
Allocation concealment?	Unclear	Information not available
Blinding? All outcomes	Yes	Double-dummy
Incomplete outcome data addressed? All outcomes	Unclear	“The efficacy analysis set (EAS), defined as all randomised subjects who took at least 1 dose of double-blind treatment and who contributed at least 1 evening PEF diary entry after receiving randomised study medication, was used in the primary analysis. Sensitivity analyses of evening PEF were performed using the per protocol (PP) analysis set.”
Free of selective reporting?	Unclear	Not clear whether OCS-treated exacerbations collected in the study