Safety and Efficacy Study of mFOLFOX6 + Panitumumab Combination Therapy and 5-FU/LV + Panitumumab Combination Therapy in Participants With Chemotherapy-naïve Unresectable Advanced Recurrent Colorectal Carcinoma

The drug being tested in this study is called panitumumab. Panitumumab is being tested to treat people who have advanced/recurrent colorectal carcinoma of KRAS wild-type. This study will look at the efficacy and safety of 5-FU/LV + panitumumab(Pmab) combination therapy or mFOLFOX6 + Pmab combination therapy in the participants. The study will enroll 164 patients. All participants will receive 6 cycles of Protocol Treatment \[1\]: Pmab 6 mg/kg, DIV, at Day 1, OXA 85 mg/m\^2, DIV, at Day 1, l LV 200 mg/m\^2, DIV, at Day 1, 5-FU 400 mg/m\^2, IV, at Day 1, 5-FU 2400 mg/m\^2, CIV, at Day 2 once every two weeks from cycle 1 through cycle 6. Then they will be randomly assigned (by chance, like flipping a coin) to one of the treatment groups. * Group A * Group B This multi-center trial will be conducted in Japan. The overall time to participate in this study is approximately 20 months.