As-needed ICS-LABA in Mild Asthma: What Does the Evidence Say?

For the last three decades, the guidelines for asthma management have supported a stepwise therapeutic approach, based on the administration of controller medications (especially inhaled corticosteroids) complemented by on-demand use of rescue medication. Classically, the rescue medication recommended comprised short-acting β agonists (SABA). Some years ago, the use of Symbicort Maintenance and Reliever Therapy (SMART) demonstrated the benefits of a combination of budesonide-formoterol, an inhaled corticosteroid, and a long-acting β agonist (ICS-LABA) as rescue medication in moderate and severe asthma. The results were enthusiastically received, and this therapeutic option was adopted in the guidelines for moderate to severe asthma patients. Recently, four trials (two randomised placebo control trials under the auspices of the SYGMA project and two real-life studies, Novel START, and the PRACTICAL trial) have explored the potential benefits of substituting SABA with budesonide-formoterol as rescue medication in mild asthma patients. The SYGMA 1 and 2 studies showed that the combination with formoterol-budesonide as rescue medication provides better asthma control than short-acting β-agonists alone in GINA step 2 patients, although the superiority was slight. Compared to budesonide maintenance therapy, the fixed combination of ICS-LABA on demand provides poorer asthma control. Regarding exacerbations, the fixed dose ICS-LABA combination on demand showed the same benefits for the prevention of exacerbations as chronic ICS treatment in mild asthma patients. The Novel START study, which assessed a population with milder symptoms, concluded that the fixed dose ICS-LABA combination used as needed was superior to SABA (albuterol) as needed for the prevention of asthma exacerbations. These results in fact show that, in undertreated GINA step 2 with only SABA as needed, ICS-LABA is more effective than SABA. The authors of PRACTICAL concluded that the study provided modest evidence that the ICS-LABA combination used as-needed for symptom relief reduces the rate of severe exacerbations compared with maintenance low-dose budesonide plus terbutaline as needed, although the study was not limited to mild asthma since according to the treatment consumed, it was evident that they had recruited some moderate asthma patients. Despite this poor evidence, and ignoring the clinical histological benefits of chronic inhaled corticosteroids (especially when administered promptly), GINA 2019 recently recommended daily low dose ICS or ICS-LABA as needed as a first option for step 2 patients. For step 1, symptom-driven or as-needed treatment with ICS-LABA is recommended rather than SABA alone (the preferred option until the last GINA update). Finally, the SIENA study showed that 73% of patients with mild asthma do not have an eosinophilic phenotype and that these patients have a similar clinical response to ICS (mometasone) and antimuscarinic drugs (tiotropium), results that challenge the indication of a drug combination that incorporates ICS as a first option. Overall, we believe there is insufficient evidence for the systematic recommendation of as-needed ICS-LABA instead of SABA on request for GINA step 1 or as a replacement for chronic ICS in GINA step 2.