Real-World Effectiveness of Add-Onfremanezumab in Patients Receiving OnabotulinumtoxinA for the Prevention of Chronic Migraine in a US Tertiary Headache Center: A Retrospective Chart Review Study

Background: Concomitant fremanezumab, a calcitonin gene-related peptide (CGRP) pathway monoclonal antibody (mAb), and onabotulinumtoxinA (onabotA) improve treatment response compared with onabotA alone in patients with chronic migraine (CM). Methods: This was a single-center, retrospective, observational study that assessed treatment response (change over time in monthly headache days [MHD] and pain intensity [PI]) in adult patients with CM receiving fremanezumab as add-on therapy to onabotA for CM prevention. Results: In the study population (N = 116, age 50.0 ± 13.1, female 85.3%, pre-index onabotA use 46.5 ± 34.2 months) receiving concurrent onabotA and fremanezumab for 17.5 ± 11.6 months, MHD decreased by 3.60 days (95% confidence interval [CI]: −5.26, −1.94, p < 0.001) and PI was reduced by 0.43 (95% CI: −0.77, −0.09, p = 0.012) at the final visit. Statistically significant reductions were seen in both MHD (−4.61, 95% CI: −6.84, −2.39; p < 0.001) and PI (−0.52, 95% CI: −0.84. −0.09; p = 0.017) among patients naïve to mAbs against CGRP or its receptor. No unexpected adverse events were observed. Conclusion: Concomitant fremanezumab and onabotA for CM prevention were effective at reducing the number of MHD and lessening PI, particularly in patients with difficult-to-treat CM who are naïve to mAbs against CGRP or its receptor.