Background and importance Fremanezumab is a humanised monoclonal antibody (IgG2) that binds to the calcitonin gene-related peptide (CGRP). CGRP is a neuropeptide that, in addition to modulating nociceptive signals, is a vasodilator that is associated with migraine. CGRP levels have been found to increase significantly during migraine and normalise with headache relief.

Aim and objectives To study the effectiveness and security of fremanezumab in migraine prophylaxis after 3 months of treatment.

Material and methods Retrospective observational study. All patients with more than 3 months of fremanezumab treatment in our hospital were included.

Data collected: sex, age, previous biological therapy, dosage regimen, moderate-severe migraine days per month and score on the Headache Impact Test-6 (HIT-6), Migraine Dissability Assessment Scale (MIDAS) and any adverse event.

Results Forty-five patients were included with a median age of 43 (23–70) years of whom 39 (86.7%) were women. Effectiveness data could be extracted for 35 of them.

No patient had any other previous biological treatment for migraine. 32% of patients were treated with fremanezumab 675 mg once every 3 months and the remainder with 225 mg monthly.

Patients presented pre-baseline versus after 3 months (mean ± standard deviation): 17.7 ± 7.2 vs 10.9 ± 9.4 migraine days/month (p<0.001); MIDAS scale: 94.8 ± 80.4 vs 82.3 ± 102.7 (p>0.1) and HIT-6 scale: 65.4 ± 9.8 vs 63.2 ± 11 (p>0.01).

Treatment was effective (reduced by half the number of migraine days per month) in 53% (20 patients). 5.7% of patients (n=3) were discontinued due to a response of less than 30%. Of the 3 patients who did not respond, 2 switched to galcanezumab and 1 to botulinum toxin.

31% patients presented some type of adverse event. Most of them were due to reactions in the area of administration, asthenia and gastrointestinal disorders, and all were of mild-moderate intensity.

Conclusion and relevance Fremanezumab has demonstrated consistent efficacy in some patients by achieving a fast reduction in the number of migraine days per month, although the reduction in pain and disability was not shown to be statistically significant.

Conflict of interest No conflict of interest