In 203 chronic migraine patients who had failed three or more preventive treatments, all three anti-CGRP antibodies were similarly effective over 12 months, with 84–100% achieving at least 50% reduction in migraine disability scores.
84.4–100% disability improvementAt 12 months, 84.4–100% of treatment-resistant chronic migraine patients achieved at least 50% reduction in MIDAS disability score on anti-CGRP antibody therapy.
What the researchers found
All three anti-CGRP monoclonal antibodies showed similar effectiveness in this treatment-resistant population, with only 17.2% of patients dropping out over the study period.
Using the MIDAS disability score, 89.5–100% of patients achieved at least 50% reduction at various follow-up points, and 84.4–100% maintained this at 12 months. By comparison, the traditional ≥50% reduction in monthly migraine days was achieved by only 36.4–66.6% of patients — substantially lower.
This discrepancy suggests that MIDAS captures functional improvements (less disability per migraine day, better coping) that raw migraine day counts miss. Monthly analgesic use also decreased substantially, with 51.1–75.7% achieving ≥50% reduction.
84.7% of enrolled patients also had medication overuse at baseline. No severe adverse events were recorded. Fewer baseline migraine days predicted better early response.
Why it matters
These patients represent the hardest-to-treat migraine population — chronic migraine with multiple prior treatment failures and medication overuse. Showing that anti-CGRP antibodies are effective and safe in this group for up to 12 months provides crucial real-world evidence. The finding that disability scores capture treatment benefits better than migraine day counts has important implications for how treatment success is measured and how insurance reimbursement criteria are set.
How the study worked
This was a single-center prospective cohort study at an Italian Headache Center enrolling 203 consecutive chronic migraine patients resistant to ≥3 previous preventive treatments. Patients received erenumab (47.2%), galcanezumab (36.5%), or fremanezumab (16.3%) for up to 12 months. Outcomes included monthly migraine days (MMDs), analgesic use, MIDAS score, HIT-6 score, and Patient Global Impression of Change. Responder rates (≥50%, ≥75%, 100% MMD reduction) were calculated at multiple follow-up points. Predictors of response were also assessed.
What this study cannot tell us
This was a single-center study in Italy, which may limit generalizability to other populations and healthcare systems. There was no placebo control group. The three antibodies were not randomized but prescribed based on clinical judgment, making direct comparisons between them less reliable. The 12-month follow-up, while substantial, may not capture longer-term outcomes or late adverse effects.
How to read the evidence
This is a prospective cohort study with 203 patients and up to 12 months of follow-up. While it provides valuable real-world evidence, it lacks randomization and a control group, and was conducted at a single center.
When this study was published
Published in 2022, this study reflects current clinical practice with anti-CGRP antibodies. The Italian reimbursement criteria discussed remain relevant to ongoing policy debates in multiple countries.
The bigger picture
Access to anti-CGRP therapies varies widely by country, often governed by strict criteria including minimum migraine day reductions to continue reimbursement. This study argues that disability-based measures like MIDAS better capture real-world treatment benefits than migraine day counts, potentially allowing more patients to maintain access to these effective but expensive treatments. The findings are particularly relevant in healthcare systems where cost-effectiveness criteria determine treatment access.
Questions still open
- Should treatment continuation criteria for anti-CGRP antibodies be based on disability scores rather than migraine day reduction?
- Why do disability improvements exceed migraine day reductions — are patients having less severe attacks or coping better?
- What predicts long-term response beyond 12 months in this treatment-resistant population?
Common questions
Do anti-CGRP antibodies work for people who haven't responded to other migraine treatments?
Are all three anti-CGRP antibodies equally effective?
Read the original research
Long-Term Effectiveness of Three Anti-CGRP Monoclonal Antibodies in Resistant Chronic Migraine Patients Based on the MIDAS score.
CNS drugs, 36(2), 191-202
Citation
Iannone, Luigi Francesco; Fattori, Davide; Benemei, Silvia; Chiarugi, Alberto; Geppetti, Pierangelo; De Cesaris, Francesco. (2022). Long-Term Effectiveness of Three Anti-CGRP Monoclonal Antibodies in Resistant Chronic Migraine Patients Based on the MIDAS score.. CNS drugs, 36(2), 191-202. https://doi.org/10.1007/s40263-021-00893-y