Inhaled fosamprenavir for laryngopharyngeal reflux: Toxicology and fluid dynamics modeling

Objectives Approximately 25% of Americans suffer from laryngopharyngeal reflux (LPR), a disease for which no effective medical therapy exists. Pepsin is a predominant source of damage during LPR and a key therapeutic target. Fosamprenavir (FOS) inhibits pepsin and prevents damage in an LPR mouse model. Inhaled FOS protects at a lower dose than oral; however, the safety of inhaled FOS is unknown and there are no inhalers for laryngopharyngeal delivery. A pre‐Good Lab Practice (GLP) study of inhaled FOS was performed to assess safety and computational fluid dynamics (CFD) modeling used to predict the optimal particle size for a laryngopharyngeal dry powder inhaler (DPI). Methods Aerosolized FOS, amprenavir (APR), or air (control) were provided 5 days/week for 4 weeks (n = 6) in an LPR mouse model. Organs (nasal cavity, larynx, esophagus, trachea, lung, liver, heart, and kidney) were assessed by a pathologist and bronchoalveolar lavage cytokines and plasma cardiotoxicity markers were assessed by Luminex assay. CFD simulations were conducted in a model of a healthy 49‐year‐old female. Results No significant increase was observed in histologic lesions, cytokines, or cardiotoxicity markers in FOS or APR groups relative to the control. CFD predicted that laryngopharyngeal deposition was maximized with aerodynamic diameters of 8.1–11.5 μm for inhalation rates of 30–60 L/min. Conclusions A 4‐week pre‐GLP study supports the safety of inhaled FOS. A formal GLP assessment is underway to support a phase I clinical trial of an FOS DPI for LPR. Level of Evidence NA. Fosamprenavir is a candidate pepsin‐targeting therapy for laryngopharyngeal reflux (LPR). Local delivery by inhalation could reduce dosing and was shown effective at 1/20th of the oral dose. This study makes progress toward a fosamprenavir dry powder inhaler for LPR through toxicologic analysis and fluid dynamics modeling.