Safety and Efficacy Study of MEHD7945A + FOLFIRI Versus Cetuximab + FOLFIRI as Second Line Therapy in Participants With KRAS Wild-Type Metastatic Colorectal Cancer (mCRC)

Standard 5-fluorouracil (5-FU) chemotherapy (400 milligram per square meter \[mg/m\^2\] administered as intravenous bolus and then 5-FU 2400 mg/m\^2 administered as continuous intravenous infusion over 46 +/- 2 hours) or according to local standard-of-care prescribing information's, every 2 weeks until documented disease progression or unacceptable toxicity.

Cetuximab 400 mg/m\^2 intravenous infusion as a loading dose on Day 1 Cycle 1, followed by 250 mg/m\^2 intravenous infusion weekly until documented disease progression or unacceptable toxicity.

Standard Irinotecan chemotherapy (180 milligram per square meter \[mg/m\^2\] administered as intravenous infusion over 60 +/- 30 minutes) or according to local standard-of-care prescribing information's, every 2 weeks until documented disease progression or unacceptable toxicity.

Standard Leucovorin chemotherapy (400 mg/m\^2 \[racemic form\] or 200 mg/m\^2 \[L-isomer form\] administered by intravenous infusion over 120 +/- 10 minutes) or according to local standard-of-care prescribing information's, every 2 weeks until documented disease progression or unacceptable toxicity.

MEHD7945A 1100 milligram (mg) intravenous infusion every 2 weeks until documented disease progression or unacceptable toxicity.