A phase I study of combination of panitumumab and bevacizumab in KRAS wild-type colorectal cancer patients who were previously treated with fluoropyrimidine, oxaliplatin, irinotecan, and bevacizumab.

759 Background: Clinical benefit of combination of panitumumab and bevacizumab (PB) based on the BBP strategy in third-line chemotherapy is unclear. There was no prospective data about the pharmacokinetic interaction between bevacizumab and panitumumab. Methods: This study composed two parts; 1) PB part: phase I study of PB to estimate its recommended dose, 2) CPB part: feasibility study to investigate the safety in combination of bevacizumab and panitumumab at the recommended dose in the phase I part with irinotecan (CPT-11) at the dose used in the prior chemotherapy. Inclusion criteria was as follows; 1) Age: ≥ 20 and < 76 years old, 2) performance status ≤ 1, 3) histologically colorectal adenocarcinoma with KRASwild-type, 4) patients who previously received fluoropyrimidine, oxaliplatin, CPT-11 and bevacizumab for unresectable metastatic disease. Three dose levels of panitumumab (Level 1: 6mg/kg, Level 0: 5mg/kg, Level -1: 4mg/kg) was set in PB part and starting dose level was Level 0. Bevacizumab was ...