Review the clinical presentation of chronic migraine
Discuss the current treatments for chronic migraine
Investigate and analyze the outcomes for using OnabotulinumtoxinA with CGRP monoclonal antibodies for the treatment of chronic migraine
Assess the tolerability of OnabotulinumtoxinA combined with CGRP monoclonal antibodies for the treatment of chronic migraine
Migraine headaches are one of the most common complaints encountered by providers in outpatient practice. Chronic migraine (CM) is defined as having 15 or more headache days a month, at least 8 days of which have features of a migraine headache, for more than 3 months. The calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs), fremanezumab, galcanezumab, and erenumab are FDA approved for the preventive treatment of migraine in adults, while onabotulinumtoxinA (onabot) is FDA approved specifically for chronic migraine. Data on combining Onabot and CGRP mAbs are limited because patients treated with onabot were excluded from clinical trials of CGRP mAbs. Many patients with CM who are significantly improved with onabot treatment continue to require additional medications for improved headache control. We will examine the efficacy and tolerability of the use of CGRP mAb medications as add-on therapy for patients with CM undergoing treatment with onabot who require additional preventive therapy. We conducted a retrospective chart review of patients with CM receiving treatment with onabot who have been prescribed a CGRP mAb medication. Eligible patients met ICHD-3 criteria for CM, were ≥18 years old, were being treated with onabot, and had a CGRP mAb medication added from May 2018 to May 2019. Patients were excluded if they received another new therapy during the study period or treatment with a CGRP mAb medication was <2 months. The primary outcome was the change in number of monthly headache days (MHDs) reported. The secondary outcome was change in pain severity. Our study population contained 153 patients, had an average age of 47.1 years, and most were female (90.8%). 114 (74.5%) patients reported a decrease in either MHDs or headache pain severity, with quantitative data documented in 66 patients. Of these 66 patients, the average MHDs prior to initiating onabot treatment was 25.3. After onabot treatment, an average decrease of 10.9 MHDs was reported (43.3% reduction from baseline, p=<0.0001 95%), but patients continued to have an average of 14.3 MHDs despite successful treatment. After the addition of a CGRP mAb medication, patients experienced a further decrease of 5.6 MHDs (an additional 22.3% reduction from onabot alone = <0.0001 95%). With combined therapy, patients reported an average of 8.7 MHDs, for a total decrease of 16.6 MHDs (65.6% reduction from baseline, p = <0.0001 95%). Only 13 patients (8.5%) reported side effects to the CGRP mAb medications that included constipation, injection site reaction, and/or fatigue. Our data suggests CGRP mAb medications are a well-tolerated and effective treatment option for patients with CM undergoing treatment with onabot who require additional preventive therapy. Patients with CM on onabot can experience a significant further reduction in MHDs and pain severity with the addition of a CGRP mAb medication, with side effects similar to those reported in the CGRP mAb clinical trials. Future prospective studies evaluating combination therapy are warranted.