Depomed has announced that it has finalized the Phase III clinical trial protocol for Gabapentin GR in conformance with requirements from the FDA. Gabapentin GR extended release tablets are in development for the treatment of postherpetic neuralgia (PHN), a long lasting pain condition caused by nerve damage during a shingles, or herpes zoster, viral infection. The company expects to begin enrollment later this month.

The randomized, double-blind, placebo-controlled study will include approximately 400 patients with postherpetic neuralgia. The primary goal is to evaluate 1800 mg twice-daily Gabapentin GR compared to placebo, as well as an arm to evaluate once-daily Gabapentin GR against placebo. Each patient will receive the 1800 mg dose for 8 weeks and the primary end point for the study will be a reduction in pain score as measured from baseline using the Likert pain scale, a numerical rating to assess pain intensity. A secondary endpoint, among others, will be a measurement of sleep interference, a common issue if patients experience breakthrough pain during the night.