Efficacy and Safety of Ralfinamide in Patients With Chronic Neuropathic Low Back Pain

Inclusion Criteria: * Patients must meet all of the following inclusion criteria to be eligible for enrolment into the study: 1. Patient presents in the physical/neurological examination with low back pain with or without radiation into the lower limb that must display a topography compatible with the L1 to S1 territory and/or respective sensory or motoric impairments. 2. Patient must have chronic neuropathic low back pain with a minimum intensity of "40 mm" (moderate) or greater on the Visual Analogue Scale (VAS; 100-mm) at screening, and an average of "40 mm" or more at baseline (based on prior 7 days). 3. The onset of pain has occurred at least three months, but not longer than 3 years, prior to the screening visit, as assessed by the investigator in the patient's medical history. 4. Patient is affected by current neuropathic pain (pain provoked by a lesion of the peripheral nervous system). The diagnosis should be made by a neurologist/anaesthesiologist/pain specialist and based on history, clinical evaluation and/or laboratory findings (rule out systemic cause, e.g., hypothyroidism, rheumatoid arthritis, nephropathy, diabetes \[MNSI score \>2\]) in accordance with the taxonomy of the diagnostic criteria documented in the International Association for the Study of Pain (IASP) Classification of Chronic Pain. A neurological disease must be directly correlated with pain, including pain due to spinal root compression. If radiologic data supporting the diagnosis had been obtained previously it should be documented in the patient's records. In case radiologic examinations are not available, the Investigator should consider performing these examinations, if necessary to support the diagnosis, during the screening phase. 5. Patient has one of the following causes of neuropathic low back pain: Non-cancer lumbar pain due to compression radiculopathy or post-traumatic/post-surgical lumbar radiculopathy. 6. Patient's low back pain has a clear neuropathic component, as indicated by a rating on the Pain Detect Questionnaire (PD-Q) of greater than 18. 7. Patient is 18-85 years of age, inclusive. 8. Patient is willing and able to understand and sign an approved Informed Consent Form. Exclusion Criteria: * 1\. Females who are pregnant or lactating, or of childbearing potential, defined as follows: surgically sterilized for less than one year; aged ≥ 50 years and post-menopausal condition started less than 24 months prior to the screening visit; or aged \< 50 years and …