Background and Importance Galcanezumab is a monoclonal antibody (MAB) for migraine prophylaxis. MAB has been shown to be safe and effective in reducing the number of migraine days per month in short-duration clinical trials. However, the optimal duration of therapy remains unresolved. Clinical practice guidelines recommend maintaining treatment for 12 months.

Drug is dispensed in the hospital pharmacy service, where pharmacists follow-up the effectiveness, safety and adherence of MAB.

Aim and Objectives To assess the long-term effectiveness and safety of galcanezumab in episodic migraine (EM) and chronic migraine (CM).

Material and Methods Retrospective observational study in a second-level hospital. Study period: September 2020– July 2023.

Migraine patients treated with galcanezumab were evaluated for at least a 12-month follow-up period from the start of treatment.

According to hospital protocol, after 12 months of MAB, neurologists decide whether to continue or discontinue it and re-assess 3 months later and restart MAB if migraine worsens.

Data were collected from the electronic medical record. The database included demographic variables, migraine-related variables, treatment-related variables, and adverse events (AE).

Results 64 patients, 54 CM and 10 EM, median age 48 years (76–21), women 84%. Mean of days of migraine previous to galcanezumab: 20.46±6.55 (CM) and 12±1.48 (EM).

The median duration of galcanezumab was 18.4 (1.9–34.9) months.

48 patients (n=64) completed the first 12-month of treatment. 32 patients (n=45) continued at 18 months, 19 (n=26) at 24 months, 14 (n=18) at 30 months and 8 (n=8) at 34 months. They were chronically maintained galcanezumab to prevent worsening if MAB was discontinued.

24 patients discontinued galcanezumab: lack of response (20), injection site rash (2), pregnancy (1), excellent treatment response (1). 17 patients were switched to another MAB (15: rebound; 2: injection site rash).

2 patients restart galcanezumab: after pregnancy (1) and for rebound 10 months after stop galcanezumab (1).

AE: constipation (12), injection site pain (3), dizziness (3), rhinitis ( 3), diarrhoea (2), injection site rash (2).

Conclusion and Relevance In our study, galcanezumab remained long-term effectiveness, safe, and well tolerated with few adverse events for more than 12 months in patients with episodic and chronic migraine. It was only discontinued in case of great improvement or therapeutic failure. Studies with larger samples are required to establish whether it could be used as a chronic treatment in patients with a high probability of worsening if treatment is discontinued.

Conflict of Interest No conflict of interest.