ACR: Pregabalin Soothes Fibromyalgia Pain in Randomized Trial

BOSTON, Nov. 11 -- Pain associated with fibromyalgia can be effectively relieved by pregabalin (Lyrica), reported investigators here.
In a placebo-controlled trial, patients randomly assigned to receive one of three doses of pregabalin reported pain relief at one week and continuing at nearly all time points at all dose levels through 14 weeks, Erdal Diri, M.D., of the Trinity Health Center-Medical Arts in Minot, North Dakota, told attendees at the American College of Rheumatology meeting.
"Pregabalin monotherapy demonstrated clinically meaningful symptomatic relief of fibromyalgia," said Dr. Diri.
Pregabalin was approved by the FDA for the treatment of fibromyalgia earlier this year, and is currently the only drug with an approved indication for the complex disorder.
Dr. Diri and colleagues conducted a randomized, double-blind, placebo-controlled trial in 745 patients with fibromyalgia meeting American College of Rheumatology criteria, which include a pain visual analog scale score of 40 mm or greater on a 0 to 100 mm scale, and a less than 30% reduction in pain VAS score during a one-week single-blind placebo run-in phase.
After the run-in, patients were randomly assigned to received placebo or pregabalin in doses of 300, 450, or 600 mg/d, delivered twice a day in divided doses, for 14 weeks, including a two-week dosage escalation phase and a 12-week fixed-dosage phase.
The primary efficacy measure was the last observation carried forward endpoint mean pain score. Secondary measures included pain relief assessed with the Duration Adjusted Average Change to determine the effect over the entire treatment period, and a Mixed Model Repeated Measurements analysis to address time-course and durability of response.
A total of 745 patients were enrolled, 95% female, with a mean age of 50. The median duration of fibromyalgia was 10 years, and the mean pain score at baseline was 6.7.
The researchers found that there were significant differences from placebo in the mean change from baseline to study endpoint for the mean pain score, at -0.71 in the 300-mg group (P=0.0009), -0.98 in the 450-mg group (P0.0001), and -1.00 in the 600-mg group (P0.0001).
Over the entire treatment period, the mean differences from placebo at endpoint over the entire treatment period (Duration Adjusted Average Change) were -0.38 in the 300-mg group (P=0.0200), -0.62 in the 450-mg group (P=0.0001), and -0.57 in the 600-mg group.
In the Mixed Model Repeated Measurements analysis there was pain relief among patients in all three pregabalin treatment groups by week one, and at all other weekly measurements, with the exception of one treatment group at the 11-week interval only. Dr. Diri did not specify which dosage had the anomalous measurement.
For all pregabalin groups, the Mixed Model Repeated Measurements mean scores (week 14) were significantly improved compared with placebo, Dr. Diri said.
The difference from baseline was -0.63 for the 300-mg pregabalin group (P=0.0051), -0.90 for the 450-mg group (P0.0001), and -0.96 for patients taking the 600-mg dose (P0.0001).
The most common adverse event was dizziness, occurring in 35.8% of patients on pregabalin compared with 7.6% of those on placebo, and somnolence in 18% versus 3.8%, respectively. The incidence of adverse events seen with pregabalin appeared to be dose related, Dr. Diri said.
The study was supported by Pfizer, maker of Lyrica.
Dr. Diri has received research support from the company and is a member of its speakers bureau. His co-authors are all current or former Pfizer employees.Primary source: American College of RheumatologySource reference: Duan R, et al "Efficacy of Pregabalin Monotherapy for Relief of Pain Associated with Fibromyalgia: Time Course and Durability of Pain Results of a 14-Week, Double-Blind, Placebo-Controlled Trial" ACR Meeting 2007; Abstract 715 presented Nov. 8.