Safety/Efficacy Study of Retigabine vs. Placebo in Post-Herpetic Neuralgia (PHN)

This is a Phase 2a proof of concept study evaluating the safety/efficacy of retigabine vs.
placebo in patients with post-herpetic neuralgia. After screening, patients will enter a
maximum 6 week titration period followed by a 4 week maintenance period and a 3 week taper
phase.

Inclusion Criteria:

- Ability to provide informed consent

- Male or female subjects

- 18-85 years of age

- PHN for more than 6 months after the healing of herpes zoster skin rash

- Has a pain score at screening and randomization that qualifies

Exclusion Criteria:

- Other significant pain that may potentially confound PHN pain assessment

- Previous neurolytic or neurosurgical therapy for PHN

- Subject has evidence of a progressive central nervous system (CNS) disease (e.g. CNS
lupus, tumors, multiple sclerosis, Alzheimer's), lesion, or encephalopathy

- Significant psychiatric or neuropsychiatric disorders including but not limited to
severe depression, bipolar disorder or schizophrenia spectrum disorder, history of
suicide attempt, or recent history of suicidal ideation

- Has clinically significant abnormalities on physical examination, vital signs, ECG, or
laboratory tests at the screening visit