Domínguez C, et al. - This study is planned to assess a relation between several biomarkers in peripheral blood and outcome after treatment with onabotulinumtoxin A (OnabotA). As per findings, molecular markers of trigeminovascular activation (CGRP) and endothelial dysfunction (PTX3) are associated with response to OnabotA. These markers thus might act as new biomarkers for the selection of treatment in chronic migraineurs.