Effects of onabotulinumtoxinA treatment in patients with and without allodynia: results of the COMPEL study.

Background: OnabotulinumtoxinA is effective in treating chronic migraine (CM), but there are limited data assessing how allodynia affects preventive treatment responses. This subanalysis of the 108-week, multicenter, open-label COMPEL Study assessed the efficacy and safety of onabotulinumtoxinA in people with CM with and without allodynia.

Methods: Patients (n = 715) were treated with onabotulinumtoxinA 155 U every 12 weeks for 9 treatment cycles. The Allodynia Symptom Checklist was used to identify patients with allodynia (scores ≥3). The primary outcome for this subanalysis was reduction in monthly headache days from baseline for weeks 105 to 108 in groups with and without allodynia. Other outcomes included assessments of moderate to severe headache days, disability (using the Migraine Disability Assessment [MIDAS] questionnaire), and health-related quality of life (Migraine-Specific Quality-of-Life Questionnaire [MSQ] v2). Adverse events and their relation to treatment were recorded.

Results: OnabotulinumtoxinA was associated with a significant mean (SD) reduction in headache day frequency at week 108 relative to baseline in patients with (n = 289) and without (n = 426) allodynia (- 10.8 [7.1] and - 12.5 [7.4], respectively; both P < 0.001) that was significantly greater in patients without allodynia (P = 0.044 between-subgroup comparison). Moderate to severe headache days were significantly reduced at week 108 in patients with and without allodynia (- 9.6 [6.9] and - 10.5 [7.2]; both P < 0.001); reduction was similar between groups. MIDAS scores improved significantly at week 108 (- 53.0 [50.3] and - 37.7 [53.0]; both P < 0.001), with a significant between-group difference in favor of those with allodynia (P = 0.005). Similarly, MSQ subscale scores (Role Function Preventive, Role Function Restrictive, Emotional Function) significantly improved at week 108 for patients with and without allodynia: 20.6 (21.9) and 16.9 (20.7), 28.0 (23.3) and 24.7 (22.7), and 27.6 (26.5) and 24.9 (26.1), respectively (all P < 0.001). OnabotulinumtoxinA was well tolerated in patients with and without allodynia.

Conclusion: Results indicate that onabotulinumtoxinA is associated with reductions from baseline in multiple efficacy outcomes for up to 108 weeks whether or not allodynia is present. The allodynia group showed a smaller treatment response for reduction in headache days, but a similar or greater treatment response for improvement in other measures. No new safety concerns were identified.