Onabotulinum Toxin A (BoNTA) in the Treatment of Chronic and High-Frequency Episodic Migraine: A Real-World Study

Background/Objectives. Although onabotulinumtoxinA (BoNTA) is an established therapy for chronic migraine (CM), its effectiveness in high-frequency episodic migraine (HFEM) remains uncertain. We conducted an 18-year, single-center, retrospective study of patients treated with BoNTA for CM or HFEM. Methods. We included 136 patients with CM and 71 with HFEM who had previously received multiple oral preventive therapies, who received BoNTA using an injection paradigm based on the PREEMPT protocol. Clinical and laboratory data were collected. Results. Responder rates, defined as a ≥50% reduction in monthly headache days, were 65.4% in CM and 71.8% in HFEM. Both groups showed a significant reduction in the frequency of headache days and headache intensity and improved response to symptomatic treatment. The mean duration of benefit among responders was 3.66 (SD 2.12) months in CM and 3.78 (SD 1.11) months in HFEM. No statistically significant associations were detected between responder status and either the duration of previous preventive treatment or the neutrophil-to-lymphocyte ratio. Responders with CM showed a non-significant tendency to have used a lower number of preventive treatments compared with partial responders plus non-responders. At the end of follow-up, 42.6% of CM and 57.8% of HFEM patients remained on BoNTA. Conclusions. In this retrospective uncontrolled cohort, reductions in headache frequency and other clinical improvements were observed during BoNTA treatment in patients with CM and HFEM. Because this study lacked a control group, these findings cannot establish the efficacy of BoNTA in HFEM and should be interpreted as exploratory.