The efficacy of pregabalin for the treatment of neuropathic pain in Japanese subjects with moderate or severe baseline pain

Abstract

Purpose: Although analyses of pooled clinical trial data have reported how international populations respond to pregabalin by baseline neuropathic pain (NeP) severity, no studies have evaluated this specifically in patients from Japan. Thus, this post hoc pooled analysis evaluated the efficacy of pregabalin in Japanese subjects for treating moderate or severe baseline NeP. Patients and methods: Data were pooled from three placebo-controlled trials enrolling Japanese subjects with postherpetic neuralgia (PHN), diabetic peripheral neuropathy (DPN), and spinal cord injury (SCI). The efficacy of pregabalin was evaluated by baseline pain severity (moderate or severe NeP). The trials on PHN and DPN included a 1-week titration of pregabalin from 150 mg/day to 300 or 600 mg/day; the SCI trial included a 4-week dose optimization phase (150 mg/day, titrated up to 600 mg/day). Treatment durations were 13-16 weeks (excluding 1-week taper periods), and pregabalin was administered in two divided doses per day. Results: Mean baseline pain scores and demographic characteristics were comparable between treatment cohorts. Pregabalin treatment significantly reduced pain scores from baseline to endpoint compared with placebo in subjects with both moderate (P<0.001) and severe (P<0.05) baseline pain. Significant improvements in mean sleep scores from baseline to endpoint were associated with pregabalin compared with placebo in subjects with both moderate and severe baseline pain (both P<0.0001). A greater proportion of subjects in both pain cohorts achieved a ≥30% reduction in pain from baseline with pregabalin vs placebo (P<0.05). Higher proportions of pregabalin-treated vs placebo-treated subjects shifted to a less severe pain category at endpoint. Consistent with the known safety profile of pregabalin, common adverse events included dizziness, somnolence, weight gain, and peripheral edema. Conclusion: Pregabalin demonstrated efficacy for pain relief and sleep improvement with a consistent safety profile in Japanese subjects with either moderate or severe baseline pain severity.