BackgroundCurrent guidelines recommend a single inhaler maintenance and reliever therapy (SMART) regimen for moderate to severe asthma. However, evidence for the inhaled corticosteroid plus fast-onset-acting β2-agonist (ICS/FABA) as reliever therapy in management of intermittent and mild asthma patients is lacking.ObjectiveTo systematically explore efficacy and safety of the proof-of-concept of the ICS plus FABA regimen in a single inhaler as reliever therapy across children and adults with intermittent and mild persistent asthma.MethodsWe searched online bibliographic databases for randomized controlled trials (RCTs) involving the as-needed use of ICS/FABA as monotherapy in intermittent or mild asthma patients. The primary outcomes were exacerbations and the hazard ratio (HR) of the time to first exacerbation.ResultsSix RCTs (n = 1300) met the inclusion criteria. Compared with the as-needed FABA regimen, the as-needed use of ICS/FABA as monotherapy statistically reduced exacerbations (RR = 0.56, P = 0.001). Compared with regular ICS regimen, the as-needed ICS/FABA therapy had slightly higher risk of exacerbations (RR = 1.39, P = 0.011). The HR for time to first exacerbations in the ICS/FABA regimen was significant lower when compared with FABA regimen (HR = 0.52, P = 0.002) but had no difference when compared with ICS regimen (HR = 1.30, P = 0.286). The corticosteroid exposure in the daily ICS regimen was 2- to 5-fold compared with as-needed use of ICS/FABA regimen.ConclusionsOur analysis shows that the ICS/FABA as a symptom-driven therapy may be a promising alternative regimen for the patients with intermittent or mild asthma, but it needs further real-world RCTs to confirm these findings.