Inspiratory flow profile and usability of the NEXThaler, a multidose dry powder inhaler, in asthma and COPD

BACKGROUND: Inhaler selection is important when managing respiratory conditions; a patient’s inhalation technique should be appropriate for the selected device, and patients should ideally be able to use a device successfully regardless of disease severity. The NEXThaler is a multidose dry-powder inhaler with a breath-actuated mechanism (BAM) and dose counter that activates only following inhalation, so effectively an ‘inhalation counter’. We assessed inspiratory flow through the NEXThaler in two studies and examined whether inhalation triggered the BAM. METHODS: The two studies were open-label, single-arm, and single visit. One study recruited patients with asthma aged ≥ 18 years; the other recruited patients with chronic obstructive pulmonary disease (COPD) aged ≥ 40 years. All patients inhaled twice through a placebo NEXThaler. The inspiratory profile through the device was assessed for each inhalation using acoustic monitoring, with flow at and time to BAM firing, peak inspiratory flow (PIF), and total inhalation time assessed. RESULTS: A total of 40 patients were enrolled in the asthma study: 20 with controlled asthma and 20 with partly controlled/uncontrolled asthma. All patients were able to trigger the BAM, as evidenced by the inhalation counter activating on closing the device. Mean flow at BAM firing following first inhalation was 35.0 (range 16.3–52.3) L/min; mean PIF was 64.6 (35.0–123.9) L/min. A total of 72 patients were enrolled in the COPD study, with data analysed for 69 (mean forced expiratory volume in 1 s 48.7% predicted [17–92%]). As with the asthma study, all patients, regardless of airflow limitation, were able to trigger the BAM. Mean flow at BAM firing following first inhalation was 41.9 (26.6–57.1) L/min; mean PIF was 68.0 (31.5–125.4) L/min. Device usability was rated highly in both studies, with 5 min sufficient to train the patients, and a click heard shortly after inhalation in all cases (providing feedback on BAM firing). CONCLUSIONS: Inhalation flows triggering the BAM in the NEXThaler were similar between patients with controlled and partly controlled/uncontrolled asthma, and were similar across COPD airflow limitation. All enrolled patients were able to activate the device. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12890-021-01430-9.