Evaluate durability of pregabalin's effect on pain associated with fibromyalgia (FM).

Randomized, double-blind, placebo-controlled trial with 1-week single-blind placebo run-in. Patients meeting ACR diagnostic criteria were randomized to pregabalin 300, 450, or 600 mg/d (BID) or placebo for 14 weeks (2-week dosage escalation; 12-week fixed-dosage). Pain was assessed with a daily pain diary using an 11-point numeric scale. Primary efficacy parameter was the LOCF endpoint mean pain score (MPS). Sensitivity analyses were assessed using the Duration Adjusted Average Change (DAAC) and a Mixed Model Repeated Measurements (MMRM).

745 randomized patients: 95% female, mean age=50 years, median FM duration=10 years, baseline MPS=6.7. Placebo-corrected differences in mean change from baseline to endpoint in MPS: 300mg/d, -0.71 (P=0.0009); 450mg/d, -0.98 (P<0.0001); 600mg/d, -1.00 (P<0.0001). Mean differences from placebo at endpoint (adjusted for treatment duration) over the entire treatment period (DAAC): 300mg/d, -.38, P=0.0200; 450mg/d, -.62; P=0.0001 and 600mg/d,-.57 P<0.0001. In the MMRM analysis, all 3 pregabalin treatment groups demonstrated pain relief by Week 1, and every weekly assessment thereafter, with the exception of 300mg/d treatment group at Week 11. Most common AEs: dizziness (all pregabalin, 35.8% vs placebo, 7.6%); somnolence (18.0% vs 3.8%). Most AEs were mild to moderate and resolved with continued treatment.

Pregabalin demonstrated significant reduction in endpoint MPS in FM patients. The DAAC sensitivity analysis confirmed the robustness of this effect. MMRM analyses demonstrated significant pain relief by Week 1 that was maintained throughout pregabalin treatment.

Study funded by Pfizer, Inc.