Safety and efficacy of NGX-4010, a prescription strength capsaicin 8% patch, for the management of postherpetic neuralgia (PHN) in the older population

Abstract

NGX-4010, a capsaicin 8% patch, has been shown to significantly reduce pain in patients with postherpetic neuralgia (PHN). 1, 2 Integrated data from four randomized, double-blind, 12-week controlled PHN studies investigated NGX-4010 efficacy and safety in the older population subgroup (median age 80 years). Included were 305 patients (≥73 years) receiving a single 60-minute treatment with NGX-4010 and 277 patients receiving a low-dose (0.04%) capsaicin control patch. Endpoints included the mean percentage change from baseline in “average pain for the past 24 hours” Numeric Pain Rating Scale (NPRS) score and the proportion of patients with ≥30%, ≥50% or ≥2 units decrease in NPRS scores. Adverse events (AEs) were also evaluated. NGX-4010 decreased pain associated with PHN in the older patient subpopulation. NGX-4010-treated group experienced a mean percentage NPRS score reduction from baseline of 25.8% compared with 17.1% in control (p=0.0005), 35.4% of NGX-4010-treated group achieved ≥30% reduction in NPRS scores (26.0% for control, p=0.0164), 23.6% had a reduction of ≥50% in NPRS scores (12.6% for control, p=0.0009) and 33.8% had a decrease of ≥2 units (28.4% for control, p=0.0002) during weeks 2-8. Similar results were obtained during weeks 2-12. The most common AEs in the older NGX-4010 patients were capsaicin-related application site erythema, pain, papules and pruritus (>5%) and their incidence and severity was similar to the younger NGX-4010 patients. Most of these AEs were mild to moderate and self-limited. These data demonstrate that a single application of NGX-4010 can produce significant pain reduction for 12 weeks in the older patients with PHN. The most common AEs were application site events and the incidence and severity was similar between the older patients compared to the younger. This study supported by NeurogesX. (1. Backonja, Lancet Neurol,2008; 2. Backonja, Pain Med, 2010).