Table 2

Changes in outcome variables from baseline to endpoint in subjects with fibromyalgia after blinded treatment with 4.5 g or 6 g sodium oxybate, compared with placebo*

PlaceboSodium oxybate
Outcome(n=188)4.5 g (n=195)p Value vs placebo6 g (n=190)p Value vs placebo
Pain and tenderness
 Pain VAS
  n (%) of responders
   ≥30% criteria49 (26.8)81 (42.0)0.00294 (51.4)<0.001
   ≥50% criteria28 (15.3)54 (28.0)0.00369 (37.7)<0.001
   ≥80% criteria11 (6.0)22 (11.4)NS29 (15.8)0.003
Pain VAS (change in score from baseline)−11.9±2.0−19.2±2.00.010−23.4±1.9<0.001
 Tender point
  TPC (change in score from baseline), median (range)0 (−16, 5)0 (−16, 4)0.0030 (−17, 4)NS
  TPI (change in score from baseline)−5.5±1.0−9.1±1.00.007−7.8±1.0NS
  MTPS (change in score from baseline)−14.1±2.6−27.9±2.6<0.001−21.7±2.60.036
Sleep and fatigue
Fatigue VAS (change in score from baseline)−13.7±1.9−23.0±1.9<0.001−26.2±1.9<0.001
JSS (change in score from baseline), median (range)−1.0 (−20, 7)−4.0 (−18, 8)<0.001−5.0 (−20, 5)<0.001
FOSQ (change in score from baseline)1.0±0.32.1±0.30.0032.1±0.30.004
Functionality and HRQOL
 FIQ (total score)
  n (%) of total FIQ responders
   ≥14% criteria79 (43.6)119 (62.6)<0.001131 (70.8)<0.001
   ≥30% criteria54 (29.8)95 (50.0)<0.001102 (55.1)<0.001
  Total FIQ (change in score from baseline)−9.9±1.5−19.2±1.5<0.001−20.6±1.5<0.001
 PCS (change in score from baseline)3.6±0.76.4±0.70.0026.3±0.70.003
EQ-5D overall health state
 EQ-5D (change in score from baseline)5.1±2.29.2±2.2NS10.6±2.2NS
Global impression of change
PGIC responders n (%)29 (16.0)61 (32.1)<0.00171 (39.7)<0.001
CGIC responders§ n (%)34 (18.7)68 (35.4)<0.00169 (37.5)<0.001
Fibromyalgia composite responders n (%)21 (13.7)42 (26.6)0.00553 (34.0)<0.001
Functional composite responders** n (%)15 (9.8)34 (21.7)0.00440 (26.0)<0.001
  • * Except when indicated otherwise, values are the least squares mean±SEM.

  • Median values are presented due to skewed distribution of data.

  • Proportion of subjects who responded ‘very much better’ or ‘much better’.

  • § Proportion of subjects whose disease was rated ‘very much improved’ or ‘much improved’ by the investigator.

  • Includes pain VAS (≥30% reduction), FIQ total score (≥30% reduction) and PGIC responders (‘very much better’ or ‘much better’).

  • ** Includes pain VAS (≥30% reduction), PGIC (‘very much better’ or ‘much better’) and SF-36 PCS (≥6 increase) responders.

  • CGIC, clinical global impression of change; EQ-5D, EuroQol-5 dimensions self-report questionnaire; FIQ, fibromyalgia impact questionnaire; FOSQ, functional outcomes of sleep questionnaire; HRQOL, health-related quality of life; JSS, Jenkins sleep scale; MTPS, manual tender point survey; NS, not statistically significant; PCS, physical component summary; PGIC, patient global impression of change; SEM, standard error of least squares mean; SF-36, Medical Outcomes Study 36-item short-form health survey; TPC, tender-point count; TPI, tender-point index; VAS, visual analogue scale.