Background and importance The introduction of biosimilars after the end of the patenting of biologics is an opportunity for significant savings in pharmaceutical spending, contributing to the sustainability of the health system.

Aim and objectives To estimate the economic savings achieved by switching to bevacizumab biosimilar in a third level hospital.

Material and methods A descriptive observational study was conducted during 2019 to estimate the economic impact of the incorporation of bevacizumab biosimilar, one of the objectives of the Annual Management Plan of our Autonomous Community, Castilla y León. The switch was agreed with the oncology service for all patients, except those who did not meet the criteria for the indication of the drug. Variables collected were: number of patients, total annual cost and quarterly cost variation 2019/2020. To estimate the cost (€), the net unit price was used (PVL-discounts (official and laboratory) + 4% VAT), and the Farmatools application was used to obtain the data.

Results The switch began in July 2020, with the degree of penetration of 96.7% in the oncology service because 2 patients (3.3%) did not switch to the biosimilar because their indication was not included in the technical data sheet. A quarterly cut-off (July–September 2019 vs 2020) showed a similar number of patients treated with original bevacizumab (n=50) and bevacizumab biosimilar (n=58) with a total cost during those months of 194 543€ and 119 001€ respectively. Although the number of patients treated with bevacizumab biosimilar in the third quarter of 2020 was higher than in the previous year with original bevacizumab (eight more patients compared with July–September 2019), the cost was reduced by 38.8%.

In 2019, 121 patients were treated with the original bevacizumab, for a total annual cost of 945 710€ and an annual expense/patient of 7816€. In 2020, assuming a cost reduction of 38.8% and the same number of patients treated as in 2019 (121 patients), annual expenditure is estimated at 578 891€ and a saving of 366 819€ per year.

Conclusion and relevance The introduction of biosimilars is an efficient measure to reduce hospital pharmaceutical expenses, maintaining the same effectiveness and safety as the original medicine, contributing to the sustainability of the National Health System.

Conflict of interest No conflict of interest