Efficacy and Safety of LX9211 in Participants With Postherpetic Neuralgia

Inclusion Criteria: * Participant has given written informed consent to participate in the study in accordance with local regulations * Adult male and female participants ≥18 years of age at the time of screening * Postherpetic neuralgia (PHN) pain that is present for ≥3 months after healing of herpes zoster skin rash affecting a single dermatome (Participants with more than 1 involved dermatome may also be included, provided the affected dermatomes are contiguous) * Moderate to severe pain as confirmed by average pain score using scores recorded in the pain diary in the 14 days prior to randomization Exclusion Criteria: * Presence of other painful conditions that may confound assessment or self-evaluation of PHN * History of major depressive episode, active, significant psychiatric disorders * History of clinically significant drug or alcohol use disorder * PHN affecting the face * Use of opioid medications for management of PHN within the 2 months prior to Screening Visit * Use of Non-steroidal anti-inflammatory drugs (NSAIDs) for the specific treatment of PHN pain