A review of 13 open-label trials found that all five CGRP-targeting migraine drugs maintained safety, sustained migraine reduction, and achieved over 75% patient retention after one year of treatment.
>75% retention at 1 yearacross CGRP-targeting drugs — substantially higher than older migraine preventives, with sustained efficacy and no new safety concerns
What the researchers found
Across 13 open-label trials (ranging 12-264 weeks) of all five CGRP-targeting drugs for migraine prevention, no new safety concerns emerged beyond those seen in double-blind phases. More than 75% of patients remained on treatment after one year, with sustained reductions in migraine frequency and lasting quality of life improvements. Discontinuation rates were generally low, and the adverse event profile was consistent with the controlled trial data.
Why it matters
While randomized controlled trials prove a drug works, open-label extensions show whether it keeps working and stays safe over years of real-world-like use. This review confirms that CGRP-targeting peptide drugs maintain their benefits long-term with higher treatment adherence than older migraine preventives — critical information for patients and clinicians committing to ongoing therapy.
The numbers in context
13 open-label trials · 5 drugs reviewed · duration 12-264 weeks · >75% retention at 1 year · 4 erenumab, 4 galcanezumab, 3 fremanezumab, 1 eptinezumab, 1 atogepant
How the study worked
Narrative review of PubMed-indexed open-label trials of CGRP monoclonal antibodies (erenumab, galcanezumab, fremanezumab, eptinezumab) and the CGRP receptor antagonist atogepant. Safety, efficacy, and treatment adherence data were summarized and critically analyzed across 13 studies.
Who was studied
Patients with episodic and chronic migraine across 13 open-label extension trials
What this study cannot tell us
Open-label trials lack placebo control, so efficacy estimates may be inflated by placebo effects and expectation bias. Patients who tolerated the drug in the double-blind phase are preferentially enrolled, creating selection bias. Not a systematic review with formal meta-analysis. Real-world adherence may differ from trial settings.
How to read the evidence
This is a narrative review of open-label extension trials, which provide valuable long-term safety and efficacy data but are inherently less rigorous than double-blind RCTs. Open-label designs introduce placebo effect and selection bias. The consistency across 13 trials and 5 drugs strengthens the overall conclusions.
When this study was published
Published in 2023, this review captures the maturing evidence base for CGRP drugs as they transition from novel therapies to established first-line migraine preventives. Additional real-world and post-marketing data has continued to accumulate since.
The bigger picture
CGRP-targeting therapies represent the first mechanism-specific preventive treatment class in migraine history. This long-term safety and efficacy data is crucial for the field because migraine is a lifelong condition requiring ongoing treatment. The high retention rates suggest these peptide-pathway drugs have fundamentally changed the treatment experience for migraine patients, who previously often cycled through medications with intolerable side effects.
Questions still open
- Do CGRP drugs maintain efficacy beyond 5 years, or does tolerance eventually develop?
- How do real-world retention rates compare to the >75% seen in these open-label trials?
- Are there long-term cardiovascular implications of sustained CGRP blockade that might only emerge after decades of use?
Common questions
What's the difference between an open-label trial and a regular clinical trial?
Why is high treatment retention important for migraine drugs?
Read the original research
Open-label trials for CGRP-targeted drugs in migraine prevention: A narrative review.
Cephalalgia : an international journal of headache, 43(2), 3331024221137091
Citation
Raffaelli, Bianca; De Icco, Roberto; Corrado, Michele; Terhart, Maria; Ailani, Jessica. (2023). Open-label trials for CGRP-targeted drugs in migraine prevention: A narrative review.. Cephalalgia : an international journal of headache, 43(2), 3331024221137091. https://doi.org/10.1177/03331024221137091