Résumé : Objectives: To investigate the features of patients with laryngopharyngeal reflux (LPR) who did not respond to medical treatment. Study Design: Prospective uncontrolled study. Setting: Multicenter study. Methods: Patients with LPR at 24-hour HEMII-pH monitoring (hypopharyngeal-esophageal multichannel intraluminal impedance–pH) were prospectively recruited from 3 European university centers. Patients were treated with 3- to 6-month medication (proton pump inhibitor and alginate) and categorized as mild to moderate responders, high responders, or nonresponders according to Reflux Symptom Score (RSS) changes at 6 months posttreatment. The predictive value of the following outcomes was studied: epidemiologic data, HEMII-pH, gastrointestinal endoscopy findings, baseline RSS and Reflux Sign Assessment, and early therapeutic response (6-week RSS). Results: A total of 148 patients completed the evaluations, accounting for 40 mild to moderate responders (20%-60% RSS changes), 76 high responders (>60% RSS changes), and 32 nonresponders. Nonresponders presented more often with hiatal hernia and lower esophageal sphincter insufficiency when compared with mild to moderate and high responders (P =.032). Baseline otolaryngologic, digestive, and respiratory RSS and the number of pharyngeal reflux events at the HEMII-pH were predictive of the 6-month therapeutic response (P <.05). The early therapeutic response (6 weeks posttreatment) was predictive of the 6-month treatment response. Conclusion: Hiatal hernia and baseline and 6-week RSS were the most predictive indicators of therapeutic effectiveness in patients with LPR.