A retrospective evaluation of the combination of erenumab and onabotulinum toxin A for the prevention of chronic migraine.

Objective: Prior to the approval of erenumab, onabotulinum toxin A (onabot A) was the only Food and Drug Administration-approved chronic migraine preventive treatment. In this study, we assess the safety and efficacy of the combination of erenumab and onabot A for chronic migraine prevention.

Methods: This is a retrospective cohort study of patients with a diagnosis of chronic migraine receiving onabot A, who were additionally started on erenumab. Primary endpoint was a decrease in number of migraine days while on the combination treatment as compared to onabot A alone. Secondary endpoints included a decrease in headache days and reported side effects.

Results: When erenumab was added to onabot A, participants (n = 50) experienced significantly lower number of monthly migraine days (11.3 ± 9.3 vs. 14.9 ± 9.4, p < 0.001). The treatment of onabot A and erenumab also significantly lowered the number of monthly headache days (18.2 ± 10.3 vs. 20.7 ± 9.1, p = 0.042). There were no "severe" adverse effects reported in the combined treatment group.

Conclusion: This retrospective case series showed a reduction in monthly migraine and headache days with the treatment combination of erenumab and onabot A compared to onabot A alone in patients with chronic migraine.