Evident from the reports of a study of the European Journal of Neurology, OnabotulinumtoxinA not only presents high rates of efficacy in reducing headache frequency after one year of use, but also significant improvements in secondary objectives.

Chronic migraine (CM) appeared as a result of the worsening in frequency and intensity of pain in an episodic migraine (EM) patients. Patients suffered from CM experience great disability. However, preventive treatments are still underdeveloped. OnabotulinumtoxinA is a specifically approved drug for the prevention of CM in adults. Phase 4 research has found that most CM patients maintain their response in the second year of treatment. The number of studies also evaluated the response of OnabotulinumtoxinA on CM patients with controversial results. Therefore, Domínguez C et al conducted this study to assess the effectiveness of OnabotulinumtoxinA in CM after 1 year of treatment in the real-life setting and to identify clinical predictors of outcome.

This prospective study was conducted in 13 hospitals in Spain. All the 725 included patients underwent a complete medical history and examination. They were treated with OnabotulinumtoxinA on every 12 weeks for 1 year. At 3 and 12 months the author collected the data about the outcome, adverse events, abortive medication use, emergency room use and disability of drug. At 12 months, 79.3% of patients showed the reduction in the number of headaches per month, and none of the patients reported any adverse events. Unilaterality of pain, fewer days of disability per month and milder headache at baseline were correlated with good outcome. Duration of disease <12 months increased the chances of response to treatment with OnabotulinumtoxinA.

In conclusion, this study confirmed the effectiveness of OnabotulinumtoxinA after 1 year of treatment. The chances of a good outcome may be increased by starting treatment in the first 12 months after chronic migraine diagnosis.