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Study breakdown

What Happens When CGRP Migraine Drugs Stop Working: Nearly 29% of Patients Discontinue Within a Year

evidence
The takeaway

About 29% of migraine patients discontinued anti-CGRP monoclonal antibodies within an average of 9 months, primarily due to ineffectiveness, with most who continued treatment switching to a different anti-CGRP drug.

28.8% Discontinuation Rate

Nearly 1 in 3 migraine patients stopped anti-CGRP antibody treatment, primarily due to ineffectiveness, highlighting the need for better response prediction and alternative CGRP-pathway therapies

What the researchers found

Of 472 patients treated with anti-CGRP/R monoclonal antibodies, 136 (28.8%) discontinued after an average of 9.0 months. Ineffectiveness was the primary reason (70.6%), followed by loss to follow-up (13.1%) and adverse events (7.3%). Most (77.9%) discontinued within the first year. Response rates (≥50% reduction in monthly headache days) were 30.5% at 3 months, 34.6% at 6 months, and 40.0% at 12 months — but only 16.9% were responding in their last month before discontinuation. After stopping, 48.5% started new treatment, with 67.6% of those switching to a different anti-CGRP antibody.

Why it matters

Understanding what happens when anti-CGRP drugs fail is critical for the ~25-30% of patients who don't respond. This study shows that switching between anti-CGRP antibodies is the most common next step — and may be rational, since different drugs target CGRP or its receptor differently. It also highlights a significant unmet need: nearly 40% of discontinuers were lost to follow-up, suggesting many patients may be left without adequate migraine care.

How the study worked

This was a prospective cohort study at the Florence Headache Center in Italy, tracking all migraine patients who discontinued anti-CGRP/R monoclonal antibody treatment. Primary outcomes were reasons for discontinuation and treatment course. Secondary outcomes included changes in monthly headache days, response rates, medication overuse, analgesic use, and MIDAS and HIT-6 disability scores at 3, 6, and 12 months.

What this study cannot tell us

This is a single-center study, which may not represent all patient populations. The 39.7% lost to follow-up after discontinuation limits understanding of long-term outcomes. The study does not compare outcomes between different anti-CGRP antibodies. No biomarker analysis was performed to predict non-response, and the definition of treatment failure was clinical rather than standardized.

How to read the evidence

This is a prospective cohort study from a single specialized headache center, providing good-quality real-world evidence. The prospective design is stronger than retrospective analysis, but single-center data limits generalizability.

When this study was published

Published in 2024, this study reflects current clinical practice with anti-CGRP monoclonal antibodies and provides timely data on real-world treatment patterns.

The bigger picture

Anti-CGRP monoclonal antibodies represent the first migraine-specific preventive therapy class, but this study reveals their real-world limitations. With nearly one-third of patients discontinuing, there's a clear need for next-generation peptide-targeted therapies. The high rate of switching between anti-CGRP drugs suggests that the CGRP pathway remains a valid target even after initial failure, potentially supporting development of more potent or differently targeted CGRP-pathway therapies.

Questions still open

  • Can biomarkers predict which migraine patients will not respond to anti-CGRP antibodies?
  • Is switching between anti-CGRP antibodies more effective than switching to a completely different drug class?
  • What happens to the 40% of patients lost to follow-up — are they receiving adequate migraine care elsewhere?

Common questions

If one anti-CGRP migraine drug doesn't work, should I try another?
According to this study, yes — 68% of patients who started a new treatment after discontinuing one anti-CGRP antibody switched to a different one. Because different anti-CGRP drugs target the peptide or its receptor in slightly different ways, failing one doesn't necessarily mean all will be ineffective.
How long should I try an anti-CGRP migraine drug before deciding it doesn't work?
In this study, response rates improved from 31% at 3 months to 40% at 12 months, suggesting some patients respond later. However, most discontinuations happened within the first year, and only 17% of eventual discontinuers were still responding in their last month. Discuss timeline expectations with your neurologist.

Read the original research

Outcomes, unmet needs, and challenges in the management of patients who withdraw from anti-CGRP monoclonal antibodies: A prospective cohort study.

Cephalalgia : an international journal of headache, 44(11), 3331024241273968

Citation

Burgalassi, Andrea; Romozzi, Marina; Vigani, Giulia; De Icco, Roberto; Raffaelli, Bianca; Boccalini, Alberto; De Cesaris, Francesco; Calabresi, Paolo; Geppetti, Pierangelo; Chiarugi, Alberto; Iannone, Luigi Francesco. (2024). Outcomes, unmet needs, and challenges in the management of patients who withdraw from anti-CGRP monoclonal antibodies: A prospective cohort study.. Cephalalgia : an international journal of headache, 44(11), 3331024241273968. https://doi.org/10.1177/03331024241273968