Inspiratory Flow Parameters Through Dry Powder Inhalers in Healthy Volunteers and Patients with Chronic Obstructive Pulmonary Disease (COPD): Device Resistance Does Not Limit Use in COPD

Introduction: Achieving correct inhalation technique through an inhaler to ensure effective drug delivery is key to managing symptoms in patients with chronic obstructive pulmonary disease (COPD). However, many patients struggle to use their inhalers correctly, with the resultant reduction in therapeutic benefit. Consequently, appropriate inhaler choice is important to maximize clinical benefit. The primary objective of this study was to characterize inspiratory flow parameters across two Easyhaler^® inhalers and the HandiHaler^® inhaler in patients with COPD and healthy volunteers.

Methods: In this randomized, open-label, crossover study, subjects (100 patients with COPD; 100 healthy volunteers) were trained to perform inhalations of placebo powder via two variants of Easyhaler and placebo capsules via the HandiHaler inhalers. Subjects then performed three placebo inhalations through each inhaler in a random sequence. Inspiratory flow parameters were assessed, including peak inspiratory flow (PIF), for each inhaler. A parallel sub-study was conducted in patients with COPD from the main study to assess correct use of the inhalers, patient's preference, ability to learn to use the inhalers, and the feasibility of the In-Check Dial device to measure PIF values.

Results: Mean PIF rates and inspiratory volumes through the three inhalers were similar between patients with COPD and healthy volunteers, and all subjects achieved the 30 L/min PIF required for effective use of Easyhaler. Almost 70% of the 88 patients enrolled in the sub-study used the Easyhaler and HandiHaler inhalers without errors. The Easyhaler was preferred by 51% of patients, while 25% favored the HandiHaler. Teaching the use of both inhalers to almost 70% of patients was very easy. The In-Check Dial PIF values and those obtained via spirometry were strongly correlated (p<0.0001) for all three inhalers.

Conclusion: The respiratory performance of patients with COPD does not appear to be a limiting factor in the use of Easyhaler.