Study to Evaluate the Efficacy and Safety of BIIB074 in Neuropathic Pain From Lumbosacral Radiculopathy

Key Inclusion Criteria: * Has body weight ≥50 kg for men and ≥45 kg for women * Must have diagnosis of neuropathic PLSR * Has duration of neuropathic (leg) pain of at least 6 months before Screening * Has an intensity of ≥4 and ≤9 on the Numerical Rating Scale based on a paper-based question at Screening and on Day 1 that asks for the average pain intensity of neuropathic (leg) pain due to PLSR over the last week Key Exclusion Criteria: * Has planned surgical intervention for PLSR within the duration of the study. (Subjects with persistent radicular pain after prior surgery are eligible.) * Has a history of peripheral neuropathy (e.g., due to diabetes, alcohol consumption, other causes, or idiopathic) or evidence of peripheral neuropathy upon neurological examination * Has a history or risk of seizures or a history of epilepsy, clinically significant head injury, or related neurological disorders NOTE: Other protocol-defined inclusion/exclusion criteria may apply.