Chronic migraine long-term regular treatment with onabotulinumtoxinA: a retrospective real-life observational study up to 4 years of therapy

Introduction: OnabotulinumtoxinA (BoNT-A) was proved effective and safe in chronic migraine (CM) prevention by the Phase III Research Evaluating Migraine Prophylaxis (PREEMPT) and Phase IV Chronic migraine OnabotulinuMtoxinA Prolonged Efficacy open-Label (COMPEL) trials over 1 and 2 years of treatment, respectively. Real-life studies highlighted BoNT-A sustained benefits up to 3 years of administration. Aim of this retrospective real-life study was observing within a 4-year timeframe the progress of a consecutive series of CM patients treated with BoNT-A and evaluating whether long-term quarterly treatment (up to 16 cycles) confirms the outcomes of previous studies over shorter periods of therapy. Methods: One hundred nine chronic migraineurs were quarterly treated with BoNT-A according to the PREEMPT paradigm. Headache days and hours, analgesics intake and latency time together with disability were analysed at baseline, thereafter bi-annually up to 48 months. Patient responsiveness (improvement in monthly headache days and hours versus baseline) was computed at each study timepoint. Results: A significant overall decrease from baseline to the 48-month assessment (p < 0.001) was evidenced for the mean number of monthly headache days and hours, analgesics intake and latency time. Severe disability cases significantly decreased at 6 months (p < 0.001), and a progressive shift towards lower degrees of disability was observed at each subsequent timepoint. A gradual percentage increase of responsive cases was observed as treatment was repeated over time. Transitory neck pain was reported in 6 cases. Conclusions: This study appears to reconfirm the benefits of long-lasting CM prevention with BoNT-A, thus supporting quarterly treatment with BoNT-A over several year.