Real-World Evidence for Control of Chronic Migraine Patients Receiving CGRP Monoclonal Antibody Therapy Added to OnabotulinumtoxinA: A Retrospective Chart Review

INTRODUCTION: Combination use of onabotulinumtoxinA and calcitonin gene–related peptide (CGRP) monoclonal antibodies (mAbs) has the potential to be more effective than either therapy alone for migraine prevention. METHODS: This retrospective, longitudinal chart review included adults with chronic migraine treated at one clinical site with ≥ 2 consecutive cycles of onabotulinumtoxinA and ≥ 1 month of subsequent combination treatment with CGRP mAbs. Charts at time of mAb prescription (baseline) and up to four visits ~ 3, 6, 9, and 12 months post-baseline were reviewed for safety, tolerability, and outcome measures (monthly headache days [MHDs], headache intensity, and migraine-related disability [MIDAS]). RESULTS: Of 300 charts reviewed, 257 patients met eligibility criteria (mean age: 50 years; 82% women). Average headache frequency was 21.5 MHDs before initiation of onabotulinumtoxinA and 12.1 MHDs before adding CGRP mAb therapy. Prescribed mAbs were erenumab (78%), fremanezumab (6%), and galcanezumab (16%). Over the entire study, patients discontinued CGRP mAb more frequently than onabotulinumtoxinA (23 vs. 3%). Adverse events occurred in 28% of patients, most commonly constipation (9%). Compared with onabotulinumtoxinA alone (baseline), MHDs decreased significantly at all visits (mean decrease: 3.5–4.0 MHDs over ~ 6–12 months of combination treatment); 45.1% of patients had clinically meaningful improvement in migraine-related disability (≥ 5-point reduction in MIDAS score) after ~ 6 months. CONCLUSIONS: In this real-world study, combination treatment with onabotulinumtoxinA and CGRP mAbs was well tolerated, with no new safety signals identified, and was associated with additional clinically meaningful benefits. More real-world and controlled trials should be considered to further assess safety and potential benefits of combination treatment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40122-021-00264-x.