Is the Efficacy of Milnacipran in Fibromyalgia Predictable? A Data-Mining Analysis of Baseline and Outcome Variables.

Fibromyalgia (FM) is a common systemic disorder and an important public health problem estimated to affect approximately 2% to 4% of the general population.1 FM is associated with a reduced threshold for pain, generally identified by an increased sensitivity to pressure at particular points on the body. This is characterized by chronic widespread pain often accompanied by persisting fatigue, muscle stiffness, and sleep disturbances. FM is also often associated with other functional syndromes such as irritable bowel syndrome and depression. These symptoms represent an important burden for the patient and generates a high level of disability that needs to be considered and treated. Current therapeutic options are based on a multimodal approach that includes pharmacological treatment, physical exercise, and education. Antidepressants are the cornerstone of many treatment paradigms.2–6 The 5-HT and noradrenaline reuptake inhibitors are of particular interest because of their dual actions. Among them, milnacipran (MLN) has demonstrated its benefit in the treatment of patients with FM. MLN obtained a marketing authorization in the USA in 2009 and in Australia in 2011. Marketing authorization was refused in Europe in 2008. During the submission process, regulatory bodies questioned the treatment-effect size and the distribution of this effect in patients enrolled in clinical trials. The Australian agency (Therapeutic Goods Administration) considered that the overall efficacy of MLN against placebo is moderate, although clinically significant, and could be translated into a real and strong improvement in some categories of patients. The determination of the symptom domains and the identification of the “good patients” who could benefit the most from MLN are the primary objectives of this manuscript.