A Phase 1 Open-Label, Dose Escalation Study to Determine the Optimal Dose, Safety, and Activity of AAV2hAQP1 in Subjects With Radiation-Induced Parotid Gland Hypofunction and Xerostomia

Inclusion Criteria: 1. Male or female subjects ≥18 years of age. 2. History of radiation therapy for head and neck cancer. 3. Abnormal parotid gland function as judged by both absence of unstimulated parotid salivary flow and a stimulated parotid salivary flow in the targeted parotid gland \>0 and \<0.3 mL/min/gland after 2% citrate stimulation. 4. No evidence of recurrence of the primary malignancy by an otolaryngology (ears, nose, and throat \[ENT\]) assessment. Additionally, all subjects must be disease-free of head and neck cancer for at least 5 years following the end of treatment at screening, with the exception of subjects with a history of HPV+ OPC (base of tongue, oropharynx, pharynx, soft palate, tonsil) who must be disease free for at least 2 years following the end of treatment. Disease status will be determined by negative clinical examinations and computed tomography (CT) scans of the neck and chest. If subjects have had a magnetic resonance imaging (MRI) of the neck or a positron emission tomography (PET) scan within 6 months of screening, then a CT scan is not required, except for HPV+ OPC subjects who must have scans at 2 years post treatment. 5. Female subjects of childbearing potential (i.e., ovulating, pre-menopausal, and not surgically sterile) and all male subjects must use a medically accepted contraceptive regimen during their participation in the study and until all samples collected at 2 consecutive visits following AAV2hAQP1 administration are negative. Acceptable methods of contraception for male subjects include the following: * Condoms with spermicide. Acceptable methods of contraception for female subjects include the following: * Intrauterine device for at least 12 weeks prior to Screening. * Hormonal contraception (oral, implant, injection, ring, or patch) for at least 12 weeks prior to Screening. * Diaphragm used in combination with spermicide. Exclusion Criteria: 1. Pregnant or lactating women or women planning to become pregnant. 2. Any experimental therapy within 3 months before Day 1. 3. Active infection that requires the use of intravenous antibiotics and does not resolve at least 1 week before Day 1. 4. Uncontrolled ischemic heart disease (i.e., unstable angina, evidence of active ischemic heart disease on electrocardiogram \[ECG\]). 5. History of systemic autoimmune diseases affecting the salivary glands. 6. Use of systemic immunosuppressive medications (i.e., corticosteroids). o Note: Topical, inhaled, or intranasal corticosteroids are allowed. 7. Malignancy, other than head and neck cancer, within the past 3 years, with the exception of adequately treated basal cell or squamous cell carcinoma of the skin or in situ cervical carcinoma. 8. Active infections including, Epstein-Barr virus (EBV), cytomegalovirus (CMV), hepatitis B (HBV), hepatitis C (HCV), or human immunodeficiency virus (HIV) infection. 9. White blood cell count \<3000/μL, absolute neutrophil count \<1500/μL, hemoglobin \<10.0 g/dL, platelet count \<100,000/μL, or absolute lymphocyte count ≤500/μL. 10. Alanine aminotransferase and/or aspartate aminotransferase \>1.5 × the upper limit of normal (ULN), alkaline phosphatase \>1.5 × ULN, or total bilirubin \>1.5 × ULN with any elevation of liver enzymes. 11. Estimated glomerular filtration rate \<60 mL/min/1.73 m2 using the Modification of Diet in Renal Disease equation. 12. Active use of tobacco products as determined by self-reporting. 13. Allergy to iodine or shellfish, and thus unable to have sialographic evaluations. 14. Allergy or hypersensitivity to glycopyrrolate.