Lung deposition is crucial for asthma treatment. However, there is no study comparing the potential role of lung co-deposition of combination therapy (inhaled corticosteroid and long-acting β2 agonist) in the same inhaler. In moderate to severe asthmatics, an extra-fine hydrofluoroalkane combination of beclomethasone dipropionate and formoterol given via a single pressurised metered-dose inhaler (pMDI) was compared with beclomethasone dipropionate chlorofluorocarbon (CFC) pMDI and formoterol dry powder inhaler (DPI) given via separate inhalers.

In a double-blind, double-dummy, 24-week randomised clinical trial, 645 patients with moderate to severe asthma uncontrolled by regular treatment with inhaled corticosteroids received regular treatment with extra-fine fixed combination beclomethasone dipropionate 200μg/formoterol 12μg bid, or beclomethasone dipropionate (500μg bid) via CFC pMDI and formoterol (12μg bid) via DPI, or beclomethasone dipropionate (500μg bid) via CFC pMDI. The primary outcome was morning peak expiratory flow (PEF). Secondary outcomes included lung function measured at clinic, asthma symptoms and control, exacerbations.

Beclomethasone dipropionate/formoterol combination via single inhaler or via separate inhalers improved morning PEF. However, the combination via single inhaler was more effective than given via separate inhalers for asthma control. Both combination treatments were superior to beclomethasone dipropionate alone in improving lung function and asthma control. All treatments were well tolerated.

In patients with moderate to severe asthma, beclomethasone dipropionate/formoterol in a single inhaler was as effective as beclomethasone dipropionate plus formoterol and superior to beclomethasone dipropionate alone in improving lung function. For the first time with a single inhaler, beclomethasone dipropionate/formoterol was significantly superior to separate components for asthma control. This trial is registered withClinicalTrials.gov, number NCT00476268.