Longterm Therapeutic Response to Milnacipran Treatment for Fibromyalgia. A European 1-Year Extension Study Following a 3-Month Study

Objective. This double-blind, 1-year extension study investigated the longterm efficacy and safety of milnacipran 100, 150, and 200 mg/day in the treatment of fibromyalgia (FM) in completers of a 3-month European double-blind lead-in study of milnacipran 200 mg/day versus placebo. Methods. A total of 468 patients with FM successfully completing the lead-in study were either blindly maintained on milnacipran 200 mg/day (MLN200:MLN200, n = 198) or (if previously receiving placebo) rerandomized to milnacipran 100 mg/day (PBO:MLN100, n = 91), 150 mg/day (PBO:MLN150, n = 92), or 200 mg/day (PBO:MLN200, n = 87) for an additional 12 months (including a 4-week dose escalation). The main efficacy endpoint was a 2-measure composite responder rate (relative to lead-in study baseline) incorporating the weekly-recall pain score recorded on a visual analog scale and the Patient Global Impression of Change score. A panel of other assessments including the Fibromyalgia Impact Questionnaire explored the multidimensional aspects of FM. Descriptive analyses using the last observation carried forward approach were performed. Results. At the 1-year endpoint, the proportion of composite responders (relative to the lead-in study baseline) ranged from 27.5% (PBO:MLN100) to 35.9% (MLN200:MLN200), and had increased from the extension study baseline by 15.2% (PBO:MLN150) to 20.7% (PBO:MLN200 and MLN200:MLN200). At endpoint, an improvement from both baselines was shown in all groups on pain, fatigue, sleep, and quality of life measures. Up to 1 year, all doses of milnacipran were safe and well tolerated. The most common drug-related adverse events were hyperhidrosis and nausea. Conclusion. Over 1 year, milnacipran 100, 150, and 200 mg/day exhibited sustained and safe therapeutic effects on predominant symptoms of FM. Registered as trial no. NCT00757731. (First Release April 1 2011; J Rheumatol 2011;38:1403-12; doi:10.3899/jrheum.101025)