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Safety and Effectiveness of As-Needed Formoterol in Asthma Patients Taking Inhaled Corticosteroid (ICS)-Formoterol or
Helen Kathryn Reddel1, Guy Brusselle2, Rosa Lamarca3
1The Woolcock Institute of Medical Research, The University of Sydney, and Macquarie University, Sydney, Australia.
Background:
As-needed low-dose inhaled corticosteroid (ICS)-formoterol reliever is recommended in patients with asthma prescribed maintenance ICS-formoterol. Clinicians often ask whether ICS-formoterol reliever can be used with other maintenance ICS-long-acting β2-agonists.
Objective:
To evaluate the safety and effectiveness of as-needed formoterol in patients taking maintenance ICS-formoterol or ICS-salmeterol from the RELIEF study.
Methods:
RELIEF (SD-037-0699) was a 6-month, open-label study that randomized 18,124 patients with asthma to as-needed formoterol 4.5 μg or salbutamol 200 μg on top of maintenance therapy. This post hoc analysis included patients on maintenance ICS-formoterol or ICS-salmeterol (n = 5436). The primary safety outcome was a composite of serious adverse events (SAEs) and/or adverse events leading to discontinuation (DAEs); the primary effectiveness outcome was time-to-first exacerbation.
Results:
For both maintenance groups and both relievers, similar numbers of patients had ≥1 SAE and/or DAE. In patients taking maintenance ICS-salmeterol, but not ICS-formoterol, significantly more non-asthma-related and nonserious DAEs occurred with as-needed formoterol versus as-needed salbutamol (P = .0066 and P = .0034, respectively). In patients taking maintenance ICS-formoterol, there was a significantly lower risk in time-to-first exacerbation with as-needed formoterol versus as-needed salbutamol (hazard ratio [HR]: 0.82, 95% confidence interval [CI]: 0.70, 0.95; P = .007). In patients taking ICS-salmeterol maintenance, time-to-first exacerbation was not significantly different between treatment arms (HR: 0.95, 95% CI: 0.84, 1.06; P = .35).
Conclusions:
As-needed formoterol significantly reduced exacerbation risk compared with as-needed salbutamol when added to maintenance ICS-formoterol, but not to maintenance ICS-salmeterol. More DAEs were seen with ICS-salmeterol maintenance therapy plus as-needed formoterol. Further research is needed to assess whether this is relevant to as-needed combination ICS-formoterol.
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