Laryngopharyngeal reflux (LPR) causes chronic cough, throat clearing, hoarseness, and dysphagia and if left untreated can promote the development of laryngeal cancer. More than 20% of the United Stated population suffer from LPR, yet there is no effective medical therapy. Proton pump inhibitors (PPIs), which inhibit gastric acid production but do not prevent reflux events, continue to be prescribed for LPR despite their poor efficacy for this patient population, high cost ($26 billion/year), and associated risks. Pepsin, detected in the airway of these patients and now known to cause laryngeal inflammation and promote disease independent of gastric acid, is a key therapeutic target. We report preclinical studies of select HIV inhibitors that bind to and inhibit pepsin and thus hold promise for the treatment of LPR. In support, a very low incidence of LPR was found in patients taking these drugs compared to the general population. HIV inhibitors are ideal drugs to repurpose because they target a foreign virus. Thus, a repurposing approach can be used to safely perform proof of concept testing of the efficacy of a pepsin inhibitor for LPR. The Specific Aim of this project is to perform a 12-week randomized, double-blind, placebo-controlled clinical trial to assess the efficacy of fosamprenavir/Lexiva for LPR. Lexiva will be used at the FDA approved, manufacturers recommended dose for HIV for 12 weeks in medically refractory patients with clinically diagnosed moderate/severe LPR and combined multi-channel intraluminal impedance - pH (MII-pH) confirmed laryngeal reflux events. Routine clinical outcome measures for LPR (Reflux Symptom Index and Reflux Finding Score) will be documented pre- and post-treatment with Lexiva (n = 52) and placebo (n = 52). Saliva will be collected pre- and post-treatment for both pepsin protein analysis and kinetic activity assay to compare with clinical measures. There is currently no effective medical therapy for LPR and pepsin is the key therapeutic target. Identification of an FDA approved drug which inhibits pepsin allows for a clinical trial to determine efficacy using a faster and safer repurposing approach to address a significant gap.