Juvenile fibromyalgia: duloxetine delivers less pain, but fails primary outcome

  • Upadhyaya HP & al.
  • Pediatr Rheumatol Online J
  • 28 May 2019

  • International Clinical Digest
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Takeaway

  • Duloxetine posted improvement in pain severity, but failed to meet the primary outcome, improvement in 24-hour average pain severity, in a placebo-controlled randomized controlled trial (RCT) of juvenile fibromyalgia (JFM).

Why this matters

  • Findings may be used to gain the first drug approval for JFM, which affects 2.1%-6.1% of school children.

Study design

  • Phase 3b RCT of patients aged 13-17 years with JFM diagnosed by Yunus and Masi criteria.
  • Patients with a score of ≥4 on 24-hour average pain severity on the Brief Pain Inventory (BPI)-Modified Short Form were randomly assigned to placebo or starting dose of 30 mg duloxetine, with a target dose of 60 mg once-daily.
  • The primary outcome was mean change in 24-hour average pain severity on the BPI from baseline to 13 weeks.
  • Funding: Eli Lilly and Company.

Key results

  • No difference between groups on the mean change in 24-hour average pain severity (−1.62 vs −0.97; P=.052).
  • The duloxetine group was more likely to report ≥30% (52.22% vs 36.26%; P=.032) and ≥50% (40.00% vs 24.18%; P=.029) improvement in average pain severity on the BPI.
  • No new safety signals emerged vs earlier studies of children and adults, with these most common adverse events consisting of nausea, headache, and vomiting.

Limitations

  • Yunus and Masi criteria not fully validated.