Safety and Effectiveness of As-Needed Formoterol in Asthma Patients Taking Inhaled Corticosteroid (ICS)-Formoterol or ICS-Salmeterol Maintenance Therapy

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 b2-agonists.OBJECTIVE: To evaluate the safety and effectiveness of as needed formoterol in patients taking maintenance ICSformoterol 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 mg or salbutamol 200 mg 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 & DDAG;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.& COPY; 2023 The Authors. Published by Elsevier Inc. on behalf of the American Academy of Allergy, Asthma & Immunology.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). (J Allergy Clin Immunol Pract 2023;11:2104-14)