Background The availability of biosimilar infliximab (IFX) has been postulated to offer cost savings compared with innovator IFX, which could lead to patients being switched between drugs.

Purpose To analyse demographic characteristics and pathologies of patients treated with IFX and to evaluate the cost effectiveness of switching from innovator to biosimilar drug.

Material and methods This was an observational, retrospective, 6 month study. Sample: 100% adult patients treated with IFX, which was prepared in the pharmacy service. Data sources: electronic medical records (IANUS), pharmaceutical application (SIMON) and management application (SINFHOS). Analysed data: number of intravenous mixtures prepared, number of patients, age, sex, weight, diagnosis, treatment received, dosage and cost of treatment.

Results 616 intravenous mixtures were prepared during the 6 months for 189 patients included in the study (70.5% innovator IFX and 29.5% biosimilar IFX). 131 patients received innovator IFX. Average age: 47.3 years (12–83), average weight 71.7 kg (48–132 kg), 68 women (51.9%). Diagnoses: A. Crohn’s disease, 31; B. ulcerative colitis, 27; C: psoriatic arthritis, 25; D. rheumatoid arthritis, 23; E. ankylosing spondylitis, 18; F. psoriasis. 2; other, 5. 81 patients were treated with doses of 5 mg/kg and 50 patients with 3 mg/kg. 58 patients received biosimilar IFX. Average age: 42.5 years (8–72), average weight 65.8 kg (23–160 kg), 32 women (55.2%). Diagnoses: A. ulcerative colitis, 14; B. psoriatic arthritis, 11; C. Crohn’s disease, 11; D. rheumatoid arthritis, 7; E. ankylosing spondylitis, 6; F. psoriasis, 1; other, 8. 36 patients were treated with doses of 5 mg/kg and 22 patients with 3 mg/kg. In the 6 month study, innovative drug consumption cost €508 297.20 while consumption of biosimilar drug was €177 923.20 (total expenditure: €686 505.4). If all patients were treated with the biosimilar drug, the total expenditure would be €609 190.4, assuming an estimated annual saving of €144 024.

Conclusion Biosimilar drugs are a good alternative compared with innovator drugs due to the saving which can be obtained with their use. A close follow-up of patients treated with biosimilar IFX would be very important to evaluate long term efficacy and safety of the treatment.

References and/or acknowledgements Brodszky V. Budget impact analysis of biosimilar infliximab for the treatment of rheumatoid arthritis. Eur J Health Econ2014.

No conflict of interest