Study of Circular RNA Treatment in Patients With Radiation Induced Xerostomia-1

Inclusion Criteria\* 1. At least 18 years of age 2. Free from recurrence of your cancer and never have had another form of cancer for at least 2 years 3. Suffering from xerostomia and/or hyposalivation and have xerostomia symptoms which were not resolved after treatment for at least 3 months 4. Both parotid glands on imaging examination Exclusion Criteria\* 1. Any active infection 2. Heart failure, reduced kidney function or uncontrolled diabetes (Hemoglobin A1c \>=8%) 3. History of autoimmune diseases known to potentially affect the salivary glands 4. Any malignancy, other than head and neck cancer within the past 3 years except for certain skin and cervical cancers 5. Active smoker or use tobacco products or have a history of substance or alcohol abuse * Other criteria apply