Background/Purpose: :Fibromyalgia (FM) is characterized by chronic widespread pain, sleep disturbance, and fatigue. Pregabalin is approved in the US in adults for the management of FM at 300-450 mg/day.

Methods: This was a 15-week, randomized, double-blind, placebo-controlled study of flexible-dose pregabalin (75-450 mg/day) in adolescents (aged 12-17 yrs) with FM. Patients met the Yunus  and Masi diagnostic criteria for FM, and had a mean numeric daily pain rating scale (NRS) score of ≥4 (0–10, 24 hour recall period). Patients were randomized 1:1 to pregabalin or placebo.  Pregabalin or placebo doses were optimized over 3 weeks based on efficacy and tolerability to 75, 150, 300, or 450 mg/day.  Patients remained at these doses for an additional 12 weeks..  The primary outcome was change from baseline in mean pain score (NRS). Secondary outcomes included change in pain score by week, change in pain score at week 15 (with a 1 wk recall period), and Patient Global Impression of Change (PGIC). Exploratory measures were Parent Global Impression of Change (Parent GIC), a version of the PGIC completed by the patient’s parent, and Fibromyalgia Impact Questionnaire-Children (FIQ-C).

Results: A total of 107 patients were randomized (54 pregabalin, 53 placebo) and 80 completed the study (44 pregabalin, 36 placebo). The percentages of pregabalin-treated patients at each optimized dose were: 25%, 19%, 15%, and 40% at 75, 150, 300, and 450 mg/day, respectively. Improvement in mean pain score at endpoint with pregabalin vs placebo was not statistically significant, treatment difference (95% CI), -0.66 (-1.51, 0.18), P=0.121. There were statistically significant improvements with pregabalin vs placebo in change in weekly mean pain score (P<0.05 for 10 of the 15 weeks); change in pain score at week 15 (1 week recall), treatment difference (95% CI), -0.87 (-1.68, -0.05), P=0.037; PGIC with 53.1% vs 29.5% very much or much improved (P=0.013); and Parent GIC with pregabalin 51.0% vs 25.0% (P=0.011). Tolerability was consistent with the known profile of pregabalin with the exception of a higher rate of mild nausea with pregabalin; 22.2% had nausea of any severity, vs 7.8% in adults with FM in previous studies. The most frequently reported adverse events with pregabalin were dizziness, nausea, headache, weight increase, and fatigue.  Two serious adverse events occurred in one pregabalin treated patient (cholelithiasis, major depression). In each treatment group, 4 subjects discontinued due to adverse events.

Conclusion: In this study, pregabalin did not significantly improve the primary measure of mean pain score compared with placebo at endpoint in adolescent patients with FM. However, the treatment difference was similar to those observed in the adult FM studies. The adolescent study employed lower doses (75-450 mg/day) than are approved for adults with FM (300-450 mg/day; starting dose 150 mg/day). There were significant improvements in secondary endpoints measuring pain and global impression of change. Pregabalin was well tolerated in this study.  The safety profile observed in this study was generally consistent with the known profile for pregabalin with the exception of nausea, which was mostly mild.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-randomized-controlled-trial-of-pregabalin-in-adolescent-patients-12-17-years-with-fibromyalgia/