Randomized Double Blind (db) Placebo (plcb) Controlled Phase Iii Study Assessing the Efficacy of Xaliproden (X) in Reducing the Cumulative Peripheral Sensory Neuropathy (psn) Induced by the Oxaliplatin (ox) and 5-Fu/lv Combination (folfox4) in First-Line Treatment of Patients (pts) with Metastatic Colorectal Cancer (Mcrc).