Chronic Migraine Prevention in Diverse Populations: What the COMPEL Trial Reveals

Chronic migraine remains one of the most disabling neurologic conditions worldwide, with well-documented disparities in diagnosis, treatment access, and longitudinal care across racial and ethnic groups. Although preventive therapies such as onabotulinumtoxinA have established efficacy in chronic migraine, limited data have examined whether treatment responses and patient-reported outcomes differ across diverse populations.

The COMPEL trial (NCT01516892) was a 108-week, multicenter, prospective study evaluating onabotulinumtoxinA 155 U administered every 12 weeks in adults with chronic migraine. Subsequent analyses explored treatment responses among White, Asian, and Black/African American subgroups, assessing changes in monthly headache days, disability measures, and quality-of-life outcomes.¹

NeurologyLive^® spoke with Deena Kuruvilla, MD, FAHS, a board-certified neurologist and headache medicine specialist who served as a study author, about how clinicians should interpret these subgroup findings, what they suggest about equity in migraine care, and the practical implications for long-term management and adherence.

(1) Clinically meaningful differences in response vs largely comparable?

Deena Kuruvilla, MD, FAHS: Bottom line: The direction and overall magnitude of benefit looked broadly comparable across racial subgroups, with no subgroup showing an absence of effect. The analyses were not powered to test between-group differences, so clinically meaningful differences can’t be claimed definitively, but the pattern is consistent benefit across groups.

Key efficacy end points at week 108 are as follows:

• Mean change in monthly headache days (MHDs): Asian −11.8; Black/African American −11.2; White −10.5; total −10.7. All groups showed large reductions.
• ≥50% responder rate (MHDs): Asian 64.9%; Black/African American 73.3%; White 60.3%; total 62.0%.
• Early response pattern: Black/African American subgroup showed lower early response but strong response by week 108.

(2) Interpreting similar responder rates given disparities in care

Similar responder rates suggest that when patients access standardized treatment and follow-up, benefit is broadly generalizable across groups. This does not negate disparities; rather, it implies that disparities likely arise from access, diagnosis, and utilization barriers rather than intrinsic differences in drug efficacy.

Clinical takeaway: Offer treatment equitably and address structural barriers such as referral pathways, insurance requirements, transportation, time off work, and continuity of care.

(3) Patient-centered outcomes: which measure best captures benefit?

All 3 instruments capture meaningful aspects of benefit, as follows:
• HIT-6: Global headache impact on daily functioning; broadly applicable across socioeconomic contexts
• MIDAS: Productivity disability (missed or impaired work days); may underrepresent benefit in individuals not formally employed
• MSQ v2.1: Migraine-specific quality of life, including role restrictions and emotional function; captures lived experience in detail

Overall, HIT-6 provides the most universally comparable single metric, while MSQ domains offer the richest insight into patient-perceived quality-of-life improvements.

(4) Tolerability and adverse events

No new safety signals were identified. Adverse events were consistent with the known profile of onabotulinumtoxinA.

Reported outcomes:
• Any treatment-emergent adverse event (TEAE): Asian 53%; Black/African American ~61%; White ~61.9%
• TEAEs leading to discontinuation: Asian ~1%; Black/African American ~4.9%; White ~5.0%
• Most common treatment-related TEAEs: neck pain, eyelid ptosis, musculoskeletal stiffness, injection-site pain

Clinical implication: No evidence supports race-based differences in counseling or monitoring. Standard safety counseling is appropriate for all patients.

(5) Retention differences and adherence considerations

The study observed meaningful differences in retention, as follows:
• Withdrawal/discontinuation: Asian 32.6%; Black/African American ~48.8–49%; White 50.5%
• Lost to follow-up: Asian 8%; Black/African American 22%; White 11.3%.

These differences likely reflect social, cultural, or health care access factors rather than treatment tolerability. OnabotulinumtoxinA requires repeated injections every 12 weeks, making adherence sensitive to logistical barriers.

Practice implications include flexible scheduling, reminder systems, addressing transportation constraints, and emphasizing that meaningful benefit may increase over time.

REFERENCE
1. Blumenfeld AM, Charleston L, Kuruvilla D, et al. OnabotulinumtoxinA treatment among diverse racial groups: post hoc analysis of the phase 4 chronic migraine onabotulinumtoxinA prolonged efficacy open-Label (COMPEL) trial. Headache. Published online December 15, 2025. doi:10.1111/head.70007