Efficacy Study in Lumbosacral Radiculopathy

Key Inclusion Criteria: * Male or female subjects aged 18 - 80 years inclusive, at the time of signing the informed consent. * A female subject is eligible to participate if she is of: Non-childbearing potential defined as pre-menopausal females with a documented tubal ligation or hysterectomy; or postmenopausal defined as 12 months of spontaneous amenorrhea Child-bearing potential and agrees to use one of the contraception methods listed in the protocol for an appropriate period of time (as determined by the product label or investigator) prior to the start of dosing to sufficiently minimize the risk of pregnancy at that point. Female subjects must agree to use contraception until 14 days after the last dose of study medication. Male subjects must agree to use the contraception methods listed in the protocol * A diagnosis of neuropathic pain due to lumbosacral radiculopathy with the following characteristics: * Pain perceived in one or both lower limbs at sites consistent with the area innervated by the L4, L5 or S1 nerve roots, with or without other sensory symptoms in the affected areas; (typically, the pain may be perceived in the buttock, thigh, calf, leg, foot or toes). * History of the pain suggestive that the cause of lumbosacral radiculopathy is due to injury of the lumbosacral nerve root(s) by degenerative disease of the vertebrae in the lumbosacral spine or associated soft tissues including the intervertebral discs, or secondary to spinal injury and not due to i…