Background and Importance Erenumab and galcanezumab are two monoclonal antibodies (mAbs) administrated subcutaneously indicated for migraine prophylaxis in adults. As these are newly approved drugs, it is important to know their safety profile.

Aim and Objectives To analyse the adverse effects (AE) of these mAbs in real life in a tertiary hospital.

Material and Methods Observational, retrospective, 30-month study ( March 2020 – September 2022). The study included all patients diagnosed with chronic migraine (CM) or episodic migraine (EM) and who received treatment with galcanezumab or erenumab respectively.

The following variables were collected sex, age, type of migraine, duration of treatment and AE.

Data were collected through the outpatient module of the Farmatools® software and the electronic health record, Mambrino XXI®.

Results Ninety-five patients (92% female, 8% male) with a median age of 50 years (18-73) were included. Of these, 72% had CM and 28% had EM. 45% and 55% of patients received erenumab and galcanezumab respectively.

48 patients (44% erenumab, 56% galcanezumab) experienced some type of AE during treatment, considered mild-moderate in severity. Four patients (75% erenumab, 25% galcanezumab) had to discontinue treatment due to poor tolerability despite prophylactic treatment. 17 (41% erenumab, 59% galcanezumab) had injection site reaction or pain, 27 (48% erenumab, 52% galcanezumab) constipation and 4 (25% erenumab, 75% galcanezumab) nausea and vomiting. AEs were more frequent among patients with CM (65%) vs EM (35%).

Comparing the data obtained with those described in other clinical trials, it was observed that the proportion of AEs was very different from that reported in the trials. In addition, there were no cases of nasopharyngitis or respiratory tract infection described as common in the trials. No cardiovascular AEs were observed.

Conclusion and Relevance Based on the results of our study, it was observed that galcanezumab and erenumab AEs were categorised as mild-moderate. The incidence of AEs was higher for the group of patients receiving galcanezumab. In addition, a small number of patients discontinued treatment due to AEs. It is essential to know the safety profile of newly approved drugs in clinical practice so as to compare them with those described in clinical trials and to see possible differences between them that contribute to generate new evidence.

Conflict of Interest No conflict of interest