Inter-patient variability of inhaled medication lung deposition using Functional Respiratory Imaging (FRI)

<bold>Background:</bold> Inhalation medication is standard for COPD, but the specific lung areas where drugs deposit and the variability of this deposition among patients remain unclear <bold>Aims and objectives:</bold> The aim of this study is to investigate the effect of inter-patient variability in regional lung deposition of inhaled medications in a group of 20 COPD patients. <bold>Methods:</bold> Deposition of Fluticasone furoate (FLU) and Vilanterol (VIL) inhaled via a Trelegy Ellipta dry powder inhaler is numerically simulated using FRI. Patients with FEV1% ranged 22.6% to 79.4% and an inhalation profile with mean flow of 30 l/min are considered. <bold>Results:</bold> The average intrathoracic deposition of FLU constitute 23.99% of the delivered dose (DD). Inter-patient variability may extend up to 10.49% of DD. Furthermore, despite using the same inhaler and inhaling in a similar manner, a patient may experience more than double the peripheral deposition compared to another (Figure 1). <bold>Conclusions:</bold> In the examination of medication deposition in patient airways, it is important to take into account inter-patient variability. This study indicates that regional deposition can vary by more than half between different patients. It is essential not to disregard the individual characteristics of a patient's airways. Novel tools are increasingly available to assess deposition on a patient-specific level, paving the way for precision medicine.