Background and Importance In our hospital there are 568 patients with multiple sclerosis (MS) in active treatment. Administration of natalizumab is every 4 weeks, but the neurologists at our hospital have optimised the administration every 5 or 6 weeks.

Aim and Objectives Evaluate economic impact from natalizumab optimisation.

Material and Methods Retrospective observational economic study performed in a third-level hospital between January 2019 and June 2022. Demographic data (sex, age), clinical data (MS treatment, posology and quantity of cycles administered) and economic data (Laboratory Purchase Price (LPP) including VAT) collected from prescribing programme and economic management platform. Patients receiving natalizumab for at least 3 cycles were included.

According to posology, calculation of active treatment time and number of cycles saved. Comparison between theorical economic import (associated to administration every 4 weeks) and real. Analysis of changes of treatment and costs associated.

Results From 568 patients with MS, 43 are receiving natalizumab in our study period. Only 37 received more than 3 cycles of natalizumab. These 37 patients include 24 women, with an average age of 41.2 years (23-65), 4 patients were receiving natalizumab every 6 weeks, and the others every 5 weeks. 111.5 weeks of active treatment time (20-198) averaged, with 21.7 cycles (4-36) associated, meaning 229 vials of natalizumab saved.

Natalizumab’s costs according to LPP (€1302) in our study period come to €1.045.506,00. If natalizumab would have been administered every 4 weeks, its cost would come to €1.343.664,00. Savings amount to €298.158,00 globally, or to €85.188,00 annually. Of 37 patients, 4 needed to change treatment due to outbreaks. The new treatment was ocrelizumab, with a PPL of €4.666,64/vial. Total annual cost of patients’ ocrelizumab amount to €74.666,24.

Conclusion and Relevance Natalizumab’s optimisation with administration every 5 weeks has meant a total saving of €10.521,76, after having reinvested part of the savings in the new treatments with ocrelizumab, allowing our patients to access innovative therapies.

Conflict of Interest No conflict of interest