Project Abstract Dry mouth is a significant side-effect of radiation therapy for head and neck cancer patients. Several factors contribute to dry mouth. Decreased production of saliva is called hyposalivation. Poor quality and function of saliva is called salivary dysfunction. Together, these cause xerostomia, or what a patient experiences as simply dry mouth. Xerostomia can lead to tooth decay, infections, difficulty speaking, impaired swallowing, poor nutrition, and has a significant negative effect on quality of life. Doctors recommend that patients suck on hard candy, chew gum, use saliva substitutes, and/or carry a water bottle with them at all times. None of these are particularly effective. Our long-term goal is to prevent the development of long-term radiation-induced dry mouth to improve the quality of life for patients with head and neck cancer. We seek to achieve this goal by providing convincing evidence that innovative cellular therapies can safely and significantly prevent the development of long-term salivary gland dysfunction. The team of investigators tackling this project is uniquely suited to complete the work. Success would lead directly to the next phase of clinical testing. We have expertise in caring for head and neck cancer patients, developing minor salivary gland derived mesenchymal stromal cells (MSCs) as cellular therapies, and studying salivary function. The overall objective of this application is to plan and prepare for a Phase 1 trial to test the safety and tolerability of IFN-g pre-licensed minor salivary gland derived MSCs for prevention of radiation-induced xerostomia in head and neck cancer patients. To achieve our goals, we propose a milestone-based project in which we will work closely with the NIH and FDA to finalize study design for a Phase 1 safety and tolerability study, complete the clinical trial protocol, and submit regulatory documents in Aim 1. In Aim 2, we will complete all necessary milestones to activate the proposed clinical trial including safety systems, data systems, and site staff and facility preparation to ensure a smooth opening to the planned clinical trial.