The purpose of the phase 2, GT-201 clinical study is to determine if GC4419 administered
prior to intensity-modulated radiation therapy (IMRT) reduces the incidence, duration, and
severity of radiation induced oral mucositis in patients who have been diagnosed with
locally advanced, non-metastatic squamous cell carcinoma of the head and neck.

RATIONALE: Giving radiation therapy that uses a 3-dimensional (3-D) image of the tumor to
help focus thin beams of radiation directly on the tumor, and giving radiation therapy in
higher doses over a shorter period of time, may kill more tumor cells and have fewer side
effects. Monoclonal antibodies, such as cetuximab, can block tumor growth in different ways.
Some block the ability of tumor cells to grow and spread. Others find tumor cells and help
kill them or carry tumor-killing substances to them. It is not yet known whether radiation
therapy is more effective when given alone or together with cetuximab in treating patients
with head and neck cancer that has been removed by surgery.

PURPOSE: This randomized phase III trial is studying radiation therapy to see how well it
works compared with radiation therapy given together with cetuximab in treating patients who
have undergone surgery for locally advanced head and neck cancer.