Efficacy of milnacipran in the treatment of fibromyalgia syndrome: A 3-month, double-blind, placebo-controlled trial

Milnacipran has demonstrated efficacy for treating the pain and multiple symptoms associated with fibromyalgia syndrome (FMS). This trial was designed to provide further evidence to support the efficacy and safety of milnacipran in treating FMS. Patients meeting ACR fibromyalgia criteria (N=1196) were randomized to placebo (n=401), milnacipran 100 (n=399), or 200 mg/day (n=396) for 15 weeks. Primary efficacy assessments consisted of 2 stringent composite responder analyses. Syndrome responders were defined as individuals having ≥30% improvement from baseline in pain (VAS, recorded daily on a Patient Electronic Diary–PED), a rating of very much improved or much improved on the Patient Global Impression of Change (PGIC) scale, and improvement from baseline in physical function (SF-36 Physical Component Summary score). Pain responders were defined as individuals meeting the above criteria for improvement in pain and patient global impression of change. At 15 weeks, both milnacipran doses compared to placebo resulted in a statistically significant increase in the number of syndrome responders (P=.011 and P=.015, 100 and 200 mg/day, respectively). Similarly, response rates for improvement in pain were superior with milnacipran compared to placebo (P=.025 and P=.004, milnacipran 100 and 200 mg/day, respectively). Significant improvements in pain were evident as early as 1 week with milnacipran. At 3 months, secondary efficacy assessments revealed that milnacipran led to significant improvements on multiple measures of pain: PED morning recall pain, weekly recall pain, real-time pain and paper pain VAS measures (both milnacipran doses vs placebo in all measures, P<.05), as well as patient global status: PGIC (both doses, P<.001). Most commonly reported adverse events (AEs) were nausea and headache. These findings confirm that milnacipran is a safe and effective treatment for the multidimensional symptoms of fibromyalgia syndrome. Supported by Forest Laboratories and Cypress Bioscience.