Effects of Intravenous GC4419 on the Incidence and Severity of Esophagitis Due to Chemoradiotherapy for Lung Cancer

Inclusion Criteria: 1. Subjects scheduled to be treated with (definitive or adjuvant) radiation therapy in combination with chemotherapy once daily for Stage 3A/3B or post-operative Stage 2B NSCLC or limited stage SCLC 2. Treatment plan for subjects show that 5 cm of the esophagus for at least one surface, is included in the 60 Gy isodose volume. Dose volume histograms show esophagus dose exposure meet V38\>30% and/or V60\>20% 3. Age 18 years or older 4. ECOG performance status ≤ 2 5. Adequate hematologic, renal and liver function 6. Use of highly effective contraception Exclusion Criteria: 1. Metastatic disease 2. Prior radiation therapy to the region of the study cancer 3. Subjects not receiving chemotherapy 4. Grade 2 or greater esophagitis at baseline 5. Inability to provide information in the electronic symptom-reporting device 6. Receiving any approved or investigational immunotherapy, targeted therapy, hormone therapy, or biologic therapy 7. Participation in another clinical trial or use of another investigational agent within 30 days of first does of GC4419 8. Malignant tumors other than the current lung cancer within the last 5 years 9. Previous diagnosis of pneumonitis 10. Untreated, active infectious disease requiring systemic anti-infective therapy 11. Untreated HIV or active hepatitis B/C 12. Females who are pregnant or breastfeeding 13. Known allergies or intolerance to chemotherapy and similar platinum-containing compounds 14. Requirement for concurrent treatment with nitrates or other drugs that may create a risk for a precipitous decrease in blood pressure 15. Clinically significant heart disease