Background and importance High costs of biological medicines (BM) are a financial issue for hospitals. The arrival of biosimilar drugs (BS) improved their accessibilities by reducing their prices.

Aim and objectives To analyse the costs of BM administered in the hospital setting and BM dispensed in the hospital pharmacy. To evaluate the economic impact of introducing BS in our hospital.

Material and methods A retrospective observational study was performed in a tertiary hospital between 2015 and 2019. All BM were included. Botplus, electronic prescription and dispensation programmes were used as sources of information. The main variables collected were: active substance, brand name, ATC code, number of drug units dispensed and cost. Types of BD were: monoclonal antibodies (MAb), recombinant proteins (RP) and vaccines or immunoglobulins (V).

Results The number of biological active substances included in the hospital formulary was 89 in 2015 and 108 in 2019 (an increase of 21%). BS introduced during the study period were: insulin glargine, epoetin α, pegfilgrastim, rituximab, trastuzumab, etanercept, infliximab and adalimumab. BM were classified as: MAb (32%), RP (48%) and V (20%). According to the ATC index: L (39.8%), J (18.5%), B (16.7%), A (9.3%), V (4.6%), H (2.8%), R (2.8%), C (2.8%), S (1.9%) and M (0.9%).

The pharmaceutical expenditure on BM was: 8 298 177€, 9 123 228€, 10 329 683€, 10 942 396€, 12 533 034€ in 2015, 2016, 2017, 2018 and 2019, respectively. The total expense was 51 226 517€ (72.5% MAb, 27.3% RP and 0.2% V). Biological active substances with the highest budgetary impact were: infliximab (7 277 499€), adalimumab (7 023 066€ and etanercept (4 416 568€). BS expenditure during this period was 1 713 288€. Direct cost savings were 1 466 034€. The introduction of BS caused an average decrease of 18% in the prices of reference BM. The hypothetical cost in the case of not having used BS was 10 509 104€. Total savings estimated were: 11 975 408€ (56.6% infliximab BS, 19% etanercept BS and 17.1% trastuzumab BS).

Conclusion and relevance BM expenditure increased by more than 50% in the last five years, with MAb being mainly responsible. The biological active substances with the highest budgetary impact were medicines to treat immune mediated diseases. The incorporation of BS will lead to a reduction of 20% in BM costs.

Conflict of interest No conflict of interest