PROJECT SUMMARY/ABSTRACT Generalized approaches for laryngopharyngeal reflux (LPR), a prevalent and heterogeneous syndrome in which laryngeal symptoms are attributed to gastroesophageal reflux, have led to poor health outcomes, inappropriate resource utilization, and tremendous healthcare costs. As a physician scientist with advanced training in esophageal physiology and health outcomes research, my long-term career goal is to discover phenotype guided care paradigms for esophageal conditions, such as LPR, focused on distinct disease mechanism. My preliminary findings from single-arm clinical trials, observational studies, and initial translational research in LPR have generated the central hypothesis that novel diagnostic biomarkers can identify clinical-physiologic phenotypes of LPR and guide a mechanism focused treatment strategy. Thus, the research goals of this proposal are to (1) measure the efficacy of the novel therapeutic upper esophageal sphincter assist device in a rigorous biomarker targeted randomized sham-controlled trial of 78 subjects with salivary pepsin positive LPR, (2) identify phenotypes of LPR using latent class analysis of comprehensive physiologic and clinical data, and (3) compare oral microbiome between subjects with and without pepsin positive LPR. The research aims are aligned with my training goals to (1) develop expertise in advanced clinical trial methods, (2) acquire skills in phenotype design and latent class analysis, and (3) obtain experience with translational microbiome research. My outstanding and diverse mentorship team is overseen by primary mentor Dr. Samir Gupta, an expert clinical trialist that has contributed seminal discoveries in colorectal cancer screening. Co-mentors include Dr. John Pandolfino, a leading international authority and clinical researcher in esophageal physiology, and Dr. Bernd Schnabl, a physician scientist that has pioneered work in host effects on the intestinal microbiome. The exceptionally supportive and conducive institutional environment at University of California San Diego (UCSD) is a key strength of this application. UCSD’s NIH supported Clinical Translational Research Institute will provide cutting-edge clinical trial infrastructure. UCSD’s Center for Esophageal Diseases and Center for Voice & Swallowing Disorders will ensure successful subject recruitment and access to state-of-the-art diagnostic techniques. UCSD’s P30 supported Digestive Diseases Research Center directed by Dr. Bernd Schnabl, will provide leading resources in microbiomics and bioinformatics. Immediate anticipated impacts of this proposal are to inform the clinical management of LPR and shed light on a novel mechanistic pathway of inflammation in LPR, as well as enhance my career by providing unique skills in clinical trial methods and microbiome research. Ultimately, this career development proposal will launch my career as an impactful leader in multi-disciplinary clinical-translational research in the fi...