GT-201 is a randomized, double-blind, placebo-controlled, multi-center study conducted in the U.S. to evaluate GC4419 administered IV for the reduction of incidence, duration, and severity of radiation induced oral mucositis in patients receiving cisplatin plus intensity-modulated radiation therapy for post-operative, or definitive treatment of locally advanced, non-metastatic squamous cell carcinoma of the head and neck, limited to the oral cavity or oropharynx. Patients will be randomized equally to 1 of 3 treatment arms: