Analgesic Efficacy and Safety of V116517 in Subjects With Moderate to Severe Chronic Pain Due to Postherpetic Neuralgia (PHN)

Key Inclusion Criteria: 1. Subjects with chronic pain due to PHN as their primary pain condition and some degree of pain every day from this condition. 2. Clinical diagnosis of PHN based on history of painful dermatomal blistering rash resolving in a few weeks followed by persistent pain in the same region of ≥ 3 months duration. Key Exclusion Criteria: 1. Subjects with chronic pain conditions other than PHN as their predominant pain condition, including gout, pseudo gout, psoriatic arthritis, active Lyme disease, rheumatoid arthritis or any other inflammatory arthritis, fibromyalgia, neuropathic pain conditions, bursitis, or acute injury or signs of active infection in the target pain area. 2. Subjects who cannot or will not agree to stop all concomitant analgesic medications apart from specified protocol supplemental analgesic medications. 3. Subjects with a recent history of seizure within the past 5 years. 4. Subjects who use opioids more than 4 days per week. 5. Subjects with clinically unstable medical conditions, including cardiac disease (unstable atrial fibrillation, symptomatic bradycardia, unstable congestive heart failure, or active myocardial ischemia); respiratory disease; biliary tract disease; hypothyroidism; adrenal cortical insufficiency; or any other medical condition that in the investigator's opinion is inadequately treated and precludes entry into the study. 6. Subjects with a history of suicide attempts, or subjects clinically judged by the principal investigator (PI) to be at serious risk of suicide. 7. PHN-pain-condition-specific exclusions: * Subjects who received pain-control interventions including neurolytic blocks or neurosurgical procedures to the affected nerve or spinal cord segment, spinal cord, stimulators, or neuraxial infusion pumps. 8. Active-comparator-related exclusions: * Subjects who are allergic to or cannot tolerate pregabalin or acetaminophen. Other protocol specific inclusion/exclusion criteria may apply.