Background and Importance Erenumab is a new monoclonal antibody for the treatment of migraine that binds to the calcitonin gene-related peptide (CGRP) receptor to inhibit its function. Erenumab is a drug with a considerable economic impact on the hospital’s annual budget.

Aim and Objectives To evaluate the budgetary impact of the redosification of the commercial dose of erenumab 140 mg into doses of 70 mg.

Material and Methods An observational, retrospective study was conducted in a tertiary care hospital with a clean room. All patients treated with erenumab between 1 January 2019 and 30 August 2022 were included. The variables collected were: sex, age, dose prepared per patient, number of redoses per patient, and number of syringes of erenumab used. To calculate the budgetary impact of erenumab, a pharmacoeconomic study was carried out in which the savings obtained by the redosification of 140 mg in doses of 70 mg were evaluated since both commercial presentations have the same price (PTR erenumab 70 mg and 140 mg = €200). The actual cost of the treatments with redosing and the theoretical cost without redosing were calculated, considering the number of doses and the duration of treatment in each patient. The information was obtained from the corporate prescription programme and patients’ clinical records.

Results A total of 281 patients were treated with erenumab during the study period. The mean age was 46 years (range 17-75), 86.8% (n=244) women and 13.2% men (n=37). A total of 1,133 syringes of erenumab 70 mg (mean: 2; range 0-29) and 1,875 of 140 mg (mean 4; range 0-28) were consumed. The real annual cost of the treatments with redosing was €519,827; compared to a theoretical annual cost of €629,282 if the redosing had not been carried out. Therefore, the redosification of erenumab 140 mg into 70 mg has saved 547.28 syringes of erenumab 140 mg per year (€109,455). An estimated saving of €389.52 per patient was obtained by the redosification of erenumab 140 mg dose into 70 mg.

Conclusion and Relevance The results show that the repackaging of the 140 mg dose into 70 mg is a great economic saving practice and easy to implement in hospitals.

Conflict of Interest No conflict of interest