Objective: To develop responder definitions for fibromyalgia clinical trials using key symptom and functional domains.
Methods: 24 candidate responder definitions were developed by expert consensus and evaluated in 12 randomized, placebo-controlled fibromyalgia trials of 4 medications.
For each definition, treatment effects of the medication compared with placebo were analyzed using the Cochran-Mantel-Haenszel test or Chi Square test.
A meta-analysis of the pooled results for the 4 medications established risk ratios to determine the definitions that best favored medication over placebo.
Two definitions performed best in the analyses.
Both definitions included 30% or greater reduction in pain and 10% or greater improvement in physical function.
They differed in that:
• One (FM30 short version) included 30% or greater improvement in sleep or fatigue,
• And the other (FM30 long version) required 30% or greater improvement in 2 of the following symptoms: sleep, fatigue, depression, anxiety, or cognition.
In the analysis of both versions, the response rate was 15% or greater for each medication and significantly greater than placebo.
The risk ratio favoring drug over placebo (95% CI) in the pooled analysis for the FM30 short version was 1.50 (1.24, 1.82), P 0.0001 or less; the FM30 long version was 1.60 (1.31, 1.96), P 0.00001 or less. [Note: a risk ratio of 1.0 would indicate no difference vs the placebo. RR’s of 1.50 and 1.60 would indicate a 50% greater response rate than placebo required with the FM30 short version and 60% greater response rate required with the FM30 long version, respectively.]
Among the 24 responder definitions tested, 2 were identified as most sensitive in identifying response to treatment.
The identification of responder definitions for fibromyalgia clinical trials that include assessments of key symptom and functional domains may improve the sensitivity of clinical trials to identify meaningful improvements, leading to improved management of fibromyalgia.
Source: Arthritis & Rheumatism, Sep 27, 2011. PMID: 21953205 by Arnold LM, Williams DA, Hudson JI, Martin SA, Clauw DJ, Crofford LJ, Wang F, Emir B, Lai C, Zablocki R, Mease PJ. University of Cincinnati College of Medicine, Cincinnati, Ohio; University of Michigan Medical School, Ann Arbor, Michigan; Harvard Medical School/McLean Hospital, Belmont, Massachusetts; RTI-Health Solutions, Ann Arbor, Michigan; University of Kentucky, Lexington, Kentucky; Eli Lilly and Company, Indianapolis, Indiana; Pfizer, Inc., New York, New York; Jazz Pharmaceuticals, Inc., Palo Alto, California; Cypress Bioscience, Inc. San Diego, California; Swedish Medical Center, and University of Washington, Seattle, Washington, USA. [Email -