A Study of PEP503(Radio-enhancer) With Radiotherapy and Chemotherapy for Patients With Rectal Cancer

The volume of PEP503 to be administered is based on the baseline tumor volume of each patient. There will be 4 dose levels in Phase Ib.

225 mg/m2 a day, 5 days/week for 5 weeks during radiotherapy period

825 mg/m2 BID 5 days/week for 5 weeks during the radiotherapy period

Approximately 8 weeks after the completion of chemoradiotherapy, surgical resection of the tumor (total mesorectal excision, TME) will be performed once the tumor become resectable.

Intensity-modulated radiation therapy (IMRT) or intensity modulated arc therapy (IMAT) of 5,000 cGy in 25 fractions (200 cGy/fraction, 5 times/week) to gross tumor and involved nodes and 4,500 cGy in 25 fractions (180 cGy/fraction, 5 times/week) to pelvis, starting at 24 hours after PEP503 injection.