title: A multicenter, randomized, double-blind, controlled study of NGX-4010, a high-concentration capsaicin patch, for the treatment of postherpetic neuralgia.
abstract: OBJECTIVE
  To confirm the efficacy, tolerability, and safety of NGX-4010, an 8% capsaicin dermal patch (capsaicin 640 µg/cm(2) ), in patients with postherpetic neuralgia (PHN). PHN is a chronic pain disorder that can be difficult to treat and for which current treatment options are often limited by poor tolerability.
  
  
  METHODS
  A total of 418 patients were randomized to receive a single 60-minute application of NGX-4010 or a 0.04% capsaicin control patch (3.2 µg/cm(2) ) in a multicenter, double-blind, confirmatory, phase 3 study.
  
  
  METHODS
  Patients were 18-90 years old with a diagnosis of PHN, pain for at least 6 months, and an average baseline Numeric Pain Rating Scale (NPRS) score of 3-9.
  
  
  METHODS
  The primary efficacy end point was the percentage change in NPRS score from baseline to weeks 2-8.
  
  
  RESULTS
  NGX-4010 recipients had a significantly greater mean reduction from baseline in pain during weeks 2-8 compared with the control group (32.0% vs 24.4%; P=0.011). A ≥ 30% reduction in mean NPRS scores was achieved in 46% of NGX-4010 recipients compared with 34% of controls (P=0.02). Pain was significantly lower in NGX-4010 recipients than controls by week 2, and greater pain reduction was maintained throughout the remaining 12-week study period. Most treatment-emergent adverse events were application site specific (notably erythema and pain), transient, and generally mild to moderate in severity.
  
  
  CONCLUSIONS
  In patients with PHN, a single 60-minute application of NGX-4010 produced significant reduction in pain that was maintained over a 12-week period.
authors.affiliation: Swedish Pain Center, Seattle, Washington, USA.
authors.forename: Gordon A
authors.initials: GA
authors.lastname: Irving
authors.forename: Miroslav M
authors.initials: MM
authors.lastname: Backonja
authors.forename: Edwin
authors.initials: E
authors.lastname: Dunteman
authors.forename: E Richard
authors.initials: ER
authors.lastname: Blonsky
authors.forename: Geertrui F
authors.initials: GF
authors.lastname: Vanhove
authors.forename: Shiao-Ping
authors.initials: SP
authors.lastname: Lu
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Tobias
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000700:Analgesics / Q000627:therapeutic use; D002211:Capsaicin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D008297:Male; D051474:Neuralgia, Postherpetic / Q000188:drug therapy*; D010147:Pain Measurement; D012959:Socioeconomic Factors; D057968:Transdermal Patch; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D002211:Capsaicin