START (2019)

Guidelines recommend daily inhaled corticosteroids (ICS) for mild asthma, but adherence is often poor. This study investigated if as-needed budesonide-formoterol could be a non-inferior alternative to maintenance ICS for preventing severe exacerbations in mild asthma.

The START study was a randomized, double-blind, non-inferiority trial. It compared as-needed budesonide-formoterol with maintenance budesonide plus as-needed terbutaline, and with as-needed terbutaline alone, in adults and adolescents with mild asthma. The primary endpoint was the annual rate of severe asthma exacerbations.

As-needed budesonide-formoterol was non-inferior to maintenance budesonide for severe exacerbation rates (0.17 vs. 0.17 per patient-year). Both budesonide-formoterol as-needed and maintenance budesonide significantly reduced exacerbations compared to as-needed terbutaline (0.40 per patient-year). The total ICS dose was substantially lower in the as-needed budesonide-formoterol group.

For patients with mild asthma, as-needed budesonide-formoterol is an effective and ICS-sparing alternative to daily maintenance ICS for preventing severe exacerbations.

The study population was predominantly white, and the generalizability to other populations may be limited. Adherence to daily ICS in the maintenance group might have been higher than in real-world settings due to trial participation.