Early efficacy and late gain in chronic and high-frequency episodic migraine with onabotulinumtoxinA

The aim was to analyse the clinical characteristics of a long-term follow-up of patients with chronic and high-frequency episodic migraine in treatment with onabotulinumtoxinA.

Patients diagnosed with high-frequency episodic migraine (HFEM) or chronic migraine (CM) according to the International Classification of Headache Disorders 3 beta were included. A comparative analysis was carried out at each study time point identifying outcome measures according to initial diagnosis and treatment duration.

In all, 578 patients were recruited and after 24 months outcome data were collected from 100 patients: 84.0% CM and 16.0% HFEM. After 24 months, headache frequency was significantly reduced by 10.5 days from baseline, 64.0% reported a ≥50% reduction in pain intensity and 70.0% of patients had ≥50% reduction in analgesic use. Comparing baseline diagnoses, at month 6 CM patients presented higher mean reduction in frequency (CM 44.3% ± 32.6% vs. HFEM 34.6% ± 24.8%) and analgesic use (CM 53.6% ± 35.4% vs. HFEM 39.3% ± 33.2%). At month 12, the mean reduction in frequency was similar in CM and HFEM patients (CM 44.7% ± 33.4% vs. HFEM 41.2% ± 28.2%). Improvement in pain intensity, analgesic use and Migraine Disability Assessment were proportional in both diagnoses.

OnabotulinumtoxinA efficacy is significant at 6 months in frequency and analgesic intake and remains stable during follow-up, whilst the intensity of pain decreases in a stepwise manner at each time point of the analysis. The improvement in CM and HFEM patients is proportional and significant after 1 year of treatment.