A Clinical Trial to Assess the Clinical Benefit of SSR411298 as Adjunctive Treatment for Persistent Cancer Pain

The primary objective of this study is to evaluate the efficacy of SSR411298 200 mg daily compared to placebo as adjunctive treatment for persistent cancer pain based on Numeric Rating Scale (NRS). Secondary Objectives are: * To evaluate the effect of SSR411298 200 mg daily on pain, breakthrough pain frequency, background therapy utilization, mood, patient satisfaction of pain relief, nausea, constipation, healthcare utilization and quality of life; * To evaluate the tolerability and safety of SSR411298 as adjunctive treatment for persistent cancer pain; * To characterize patient disease, in terms of cancer, cancer treatment, cancer pain and cancer pain treatment; * To evaluate the pharmacokinetic (PK) exposure of SSR411298 as adjunctive treatment for persistent cancer pain; * To assess endocannabinoid plasma concentrations.