Safety of a Single Administration of AAV2hAQP1, an Adeno-Associated Viral Vector Encoding Human Aquaporin-1 to One Parotid Salivary Gland in People With Irradiation-Induced Parotid Salivary Hypofunction

The treatment of most head and neck cancer patients includes ionizing radiation (IR).
Salivary glands in the IR field suffer irreversible damage. There is no conventional
treatment available to correct this condition. Our research group has been developing an
adeno-associated virus vector based on the hypothesis that this vector is capable of safely
transferring the human aquaporin-1 (hAQP1) cDNA gene to parotid glands of adult patients with
IR-induced salivary hypofunction, resulting in an elevated salivary output. Human AQP1, the
archetypal water channel, is a plasma membrane protein that facilitates water movement across
lipid bilayers. Minipig studies have shown that the AAV2hAQP1 strategy for restoring salivary
flow to IR-damaged salivary glands is effective without untoward effects after salivary gland
delivery. As a proof of concept that AQP1 would restore saliva flow in a human population, we
recently completed a phase 1 clinical trial (06-D-0206) using an Adenovirus-based vector
encoding AQP1 to a single previously irradiated parotid gland in eleven patients using an
open label, single dose, dose-escalation design. All patients tolerated vector delivery and
study procedures well and positive objective and subjective responses were seen in five
patients, all at doses <5.8 times10(9) vp/gland. At higher doses the patients possibly
initiated an immune response to the vector and no improvement in gland function was observed.
These findings have encouraged us to pursue studies with AAV2 based vectors, which have
demonstrated lower immunogenicity and more stable expression compared with adenoviral
vectors. The purpose of this clinical protocol is to test the safety of AAV2hAQP1, with some
measures of efficacy, in adult patients with established IR-induced parotid gland
hypofunction. The targeted tissue site for the AAV2hAQP1 vector in the proposed study is a
single parotid gland. In this Phase 1 dose-escalation study, safety will be evaluated using
conventional clinical and immunological parameters. The primary outcome measure for
biological efficacy will be parotid gland salivary output.

- INCLUSION CRITERIA:

1. At least 18 years of age

2. History of radiation therapy for head and neck cancer, having received >45Gy to
the parotid gland(s) using conventional 2D and 3D treatment. If radiation therapy
was given using IMRT, the amount of radiation received by the parotid gland(s)
must exceed 15 Gy.

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 primary malignancy by otolaryngology (ENT)
assessment. Additionally, all patients must have been disease-free of head and
neck cancer for at least 5 years, a status to be determined at pre-dose screening
using negative clinical exams and PET and or CT imaging of the neck and chest.
The anatomic subset of HPV positive oropharyngeal cancer may be enrolled after 2
years post completion of therapy.

5. Willingness to practice the required birth control method ("barrier"
contraception, condoms, diaphragm) until AAV2hAQP1 is no longer detectable in
their serum or saliva.

6. Women who cannot bear children (post-menopausal or due to a surgical
intervention) also will be required to practice barrier birth control methods
until AAV2hAQP1 is no longer detectable in their serum or saliva.

7. Ability to stay at the NIH hospital for the period of time necessary to complete
each on-site phase of the protocol (3-5 days).

8. No history of allergies to any medications or agents to be used in this protocol.

9. On stable medications (greater than or equal to 2 months) for any underlying
medical conditions at time of vector administration.

EXCLUSION CRITERIA:

1. Pregnant or lactating women. Women of childbearing potential are required to have a
negative serum pregnancy test at screening and a negative urine pregnancy test within
48 hours prior to gene infusion.

2. Any experimental therapy within 3 months.

3. Any active respiratory tract infection in the 3 weeks prior to day 1 of the protocol

4. Active infection that requires the use of intravenous antibiotics and does not resolve
at least 1 week before Day 1.

5. Uncontrolled ischemic heart disease: unstable angina, evidence of active ischemic
heart disease on ECG, congestive heart failure (left ventricular ejection fraction <
45% on MUGA or echo) or cardiomyopathy.

6. Asthma or chronic obstructive pulmonary disease requiring regular inhaled or systemic
corticosteroids.

7. Individuals with a history of autoimmune diseases affecting salivary glands, including
Sjogren's syndrome, lupus, scleroderma, type I diabetes, sarcoidosis, amyloidosis, and
chronic graft versus host disease. Organ specific autoimmune conditions may be
included if clinically stable.

8. Use of systemic immunosuppressive medications (,i.e., corticosteroids). Topical
corticosteroids are allowed.

9. Malignancy, other than head and neck, within past 3 years, with the exception of
adequately treated basal cell or squamous cell carcinoma of the skin or in situ
cervical carcinoma.

10. Active infections including Epstein-Barr virus (EBV), cytomegalovirus (CMV), hepatitis
B, hepatitis C, or human immunodeficiency virus (HIV) infection.

11. WBC <3000/microL or ANC <1500/microL or Hgb <10.0 g/dL or platelets <100,000/microL or
absolute lymphocyte count less than or equal to 500/microL.

12. ALT and/or AST > 1.5 times upper limit of normal (ULN) or alkaline phosphatase >1.5
times ULN

13. Serum creatinine > 2 mg/dL.

14. Serum bilirubin measurements (total, direct, indirect) that are outside of the normal
range.

15. Individuals who are active cigarette smokers as determined by self-reporting.

16. Individuals who have an allergy to iodine or shellfish and thus are unable to have
sialographic evaluations.

17. Individuals who have an allergy or hypersensitivity to glycopyrrolate

18. Individuals whose parotid duct(s) are not clinically accessible on screening
sialography.

19. Individuals, who on sialography, have a distal stenosis that would impede vector
delivery.

20. Significant concurrent or recently diagnosed (<2 months) medical condition that, in
the opinion of the Medically Responsible Investigator, could affect the patient's
ability to tolerate or complete the study.

21. Live vaccines within 4 weeks of first infusion.

22. Individuals who have had an adverse response to prednisone (i.e. hallucinations).

23. Individuals with uncontrolled diabetes (HbA1c greater than 10%).

24. Individuals with untreated severe dental caries, pyorrhea, gingivitis, chronic
radiation mucositis or ulceration, erythroplasia, leukoplakia or other pre-malignant
conditions.