title: Long-term tolerability and maintenance of therapeutic response to sodium oxybate in an open-label extension study in patients with fibromyalgia.
abstract: BACKGROUND
  The long-term safety and therapeutic response of sodium oxybate (SXB) in fibromyalgia syndrome (FM) patients were assessed for a combined period of up to 1 year in a prospective, multicenter, open-label, extension study in patients completing 1 of 2 phase 3 randomized, double-blind, controlled, 14-week trials that examined the efficacy and safety of SXB 4.5 g, SXB 6 g, and placebo for treatment of FM.
  
  
  METHODS
  This extension study comprised an additional 38 weeks of treatment and was carried out at 130 clinical sites in 7 countries. Initial entry criteria for the previous 2 double-blind clinical trials required that patients aged ≥ 18 years met the American College of Rheumatology 1990 criteria for FM, had a body mass index (BMI) < 40 kg/m2, and had a score ≥ 50 on a 100-mm pain visual analog scale (VAS) at baseline. All patients began treatment in the extension study with SXB 4.5 g/night (administered in 2 equally divided doses) for at least 1 week, followed by possible serial 1.5 g/night dose increases to 9 g/night (maximum) or reductions to 4.5 g/night (minimum).
  
  
  RESULTS
  Of the 560 FM patients enrolled in this extension study, 319 (57.0%) completed the study. The main reason for early discontinuation was adverse events (AEs; 23.0% of patients). Patients were primarily middle-aged (mean 46.9 ± 10.8 years), female (91.1%), white (91.4%), with a mean duration of FM symptoms of 9.9 ± 8.7 years. Serious AEs were experienced by 3.6% of patients. The most frequently reported AEs (incidence ≥ 5% at any dose or overall) were nausea, headache, dizziness, nasopharyngitis, vomiting, sinusitis, diarrhea, anxiety, insomnia, influenza, somnolence, upper respiratory tract infection, muscle spasms, urinary tract infection, and gastroenteritis viral. Maintenance of SXB therapeutic response was demonstrated with continued improvement from controlled-study baseline in pain VAS, Fibromyalgia Impact Questionnaire (FIQ) total scores, and other measures. Responder analyses showed that 68.8% of patients achieved ≥ 30% reduction in pain VAS and 69.7% achieved ≥ 30% reduction in FIQ total score at study endpoint.
  
  
  CONCLUSIONS
  The long-term safety profile of SXB in FM patients was similar to that in the previously reported controlled clinical trials. Improvement in pain and other FM clinical domains was maintained during long-term use.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00423605.
authors.forename: Michael
authors.initials: M
authors.lastname: Spaeth
authors.forename: Cayetano
authors.initials: C
authors.lastname: Alegre
authors.forename: Serge
authors.initials: S
authors.lastname: Perrot
authors.forename: Youyu
authors.initials: Y
authors.lastname: Wang
authors.forename: Diane R
authors.initials: DR
authors.lastname: Guinta
authors.forename: Sarah
authors.initials: S
authors.lastname: Alvarez-Horine
authors.forename: Irwin
authors.initials: I
authors.lastname: Russell
mesh_terms: D000328:Adult; D000368:Aged; D002492:Central Nervous System Depressants / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005356:Fibromyalgia / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D012978:Sodium Oxybate / Q000627:therapeutic use*; D013995:Time
chemical_list: D002492:Central Nervous System Depressants; D012978:Sodium Oxybate