Abstract Rationale Understanding human interaction with a device in real-life settings is essential to ensure that a drug-device combination product is safe, effective, and truly usable. Engaging patients, care partners, and health care professionals (HCPs) early in device development ensures design decisions reflect real-world needs, creating products that are clinically practical, accessible, and supportive. We report our learnings from a usability study evaluating the eFlow® Nebulizer System (eFlow), designed to deliver AP01 (inhaled pirfenidone), currently being studied in patients with progressive pulmonary fibrosis (PPF) in the Phase 2b MIST Study (NCT06329401). Methods To assess the eFlow’s usability and identify potential harms from use errors, an IRB-approved usability study was conducted focused on those affected by idiopathic pulmonary fibrosis (IPF), a lung disease with similar pathophysiology to PPF. This study involved three user groups: patients living with IPF (n = 6), care partners of patients with lung conditions (n = 6), and HCPs with experience treating patients with IPF (n = 6). All participants were provided with the eFlow device and IFU. Half of the participants from each group received nebulizer and IFU training provided by a nurse trainer. The remaining half of the participants did not receive training. All participants were asked to perform and simulate a complete treatment, including critical tasks related to five evaluation activities: (1) preparation of the nebulizer for first use and treatment administration, (2) cleaning and storage of the nebulizer, (3) weekly aerosol head maintenance, (4) disinfection of the nebulizer, and (5) warning interpretation. Observations captured use errors, close calls, operational difficulties, and moderator assistance. Participants provided feedback on the device’s safety, usability, and effectiveness of its labeling. Results Key findings indicated that the most common use errors were related to tasks such as cleaning, disinfecting, and weekly maintenance, with participants performing these in the wrong order or not in accordance with the IFU. Assembly of the handset and locating warning information in the IFU were identified as operational difficulties. These findings informed updates to the IFU and the creation of an instructional video to enhance the usability of the eFlow device and IFU. Conclusions Partnering with potential end-users in this study provided critical insights to eFlow nebulizer design, usability, and instructional materials, helping to support proper use and improve patient confidence and adherence in clinical studies evaluating AP01. This abstract is funded by: The study was funded by Avalyn Pharma Inc.
Pham et al. (2026) studied this question.