A Study of the Effects of GC4419 on Radiation Induced Oral Mucositis in Patients With Head/Neck Cancer

Inclusion Criteria: 1. Pathologically-confirmed diagnosis of squamous cell carcinoma of the head and neck, defined as SCC of the oral cavity or oropharynx that will be treated with cisplatin plus concurrent IMRT Note: Patients with unknown primary tumors whose treatment plan matches the requirements specified in Inclusion Criteria #2 and #3 below are eligible for the trial. 2. Treatment plan to receive a continuous course of IMRT delivered as single daily fractions of 2.0 to 2.2 Gy with a cumulative radiation dose between 60 Gy and 72 Gy. Planned radiation treatment fields must include at least two oral sites (buccal mucosa, floor of mouth, tongue, soft palate) that are each planned to receive a total of \> 50 Gy. Patients who have had prior surgery are eligible, provided they have fully recovered from surgery, and patients who may have surgery in the future are eligible. 3. Treatment plan to receive standard cisplatin monotherapy administered either every three weeks (80-100 mg/m2 for 3 doses) or weekly (30-40 mg/m2 for 6-7 doses). The decision on which chemotherapy regimen to use in combination with IMRT and GC4419 will be at the discretion of the investigator. 4. Age 18 years or older 5. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 6. Adequate hematologic function as indicated by: * Absolute neutrophil counts (ANC) ≥ 1,500/mm3 * Hemoglobin (Hgb) ≥ 9.0 g/dL * Platelet count ≥ 100,000/mm3 7. Adequate renal and liver function as indicated by: * Serum creatinine acceptable for treatment with cisplatin per institutional guidelines * Total bilirubin ≤ 1.5 x upper-normal limit (ULN) * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 x ULN * Alkaline phosphatase ≤ 2.5 x ULN 8. Human papilloma virus (HPV) status in tumor has been documented using tumor immunohistochemistry for HPV-p16 or other accepted test 9. Serum pregnancy test negative for females of childbearing potential 10. Males and females must agree to use effective contraception starting prior to the first day of treatment and continuing for 30 days after the last dose of GC4419 11. Properly obtained written informed consent Exclusion Criteria: 1. Tumor of the lips, larynx, hypopharynx, nasopharynx, sinuses, or salivary glands 2. Metastatic disease (Stage IV C) 3. Prior radiotherapy to the region of the study cancer or adjacent anatomical sites or more than 25% of total body marrow-bearing area (potentially interfering with chemotolerance) 4. Prior induction chemotherapy 5. Receiving any approved or investigational anti-cancer agent other than those provided for in this study 6. Participation in another clinical trial or use of another investigational agent within 30 days of study entry 7. Requirement for significantly modified diet (liquids and/or solids) due to compromised oral/pharyngeal function at baseline 8. Requirement at baseline for parenteral or gastrointestinal tube-delivered nutrition for any reason 9. Malignant tumors other than head and neck cancer (HNC) within the last 5 years, unless treated definitively and with low risk of recurrence in the judgment of the treating investigator 10. Active infectious disease excluding oral candidiasis 11. Presence of oral mucositis (World Health Organization Score ≥ Grade 1) at study entry 12. Known history of HIV or active hepatitis B/C (patients who have been vaccinated for hepatitis B and do not have a history of infection are eligible) 13. Female patients who are pregnant or breastfeeding 14. Known allergies or intolerance to cisplatin and similar platinum-containing compounds 15. Requirement for concurrent treatment with nitrates or other drugs that may, in the judgment of the treating investigator, create a risk for a precipitous decrease in blood pressure