Background Etanercept is a tumour necrosis factor (TNF) inhibitor indicated for active rheumatoid arthritis (RA) as monotherapy or in combination with methotrexate. Biosimilar drugs currently commercialised are Benepali and Erelzi.

Purpose To evaluate biosimilar etanercept effectiveness in patients with RA and calculate the saving due to use them versus the original drug.

Material and methods Retrospective observational study in a cohort of patients with RA treated with a biosimilar etanercept from January 2017 to August 2018. Data collected: drug, age, sex, dose, schedule, concomitant disease-modifying antirheumatic drugs (DMARD), previous biological drugs, treatment length, baseline and final disease activity score (DAS28). Data sources: electronic medical records and outpatients’ electronic prescription. Costs considered were hospital average prices.

Results Thirty-two patients were included; but only 16 had DAS28 documented. 81.3% were female, median age 61 (IQR 50.75–66.75) years and median treatment duration 186 (IQR 107.25–263.75) days. All patients were treated with a concomitant DMARD. Baseline and final DAS28 means differences were statistically significant (p=0.002). 56.3% of patients were naive, whose DAS28 difference was statistically significant (p=0.006). Twenty-five per cent of patients received etanercept as a third line of treatment, with a DAS28 difference statistically not significant (p=0.496).

Eight (50%) patients received Benepali, 75% were female, median age 61 (IQR 54.00–66.25) years and median treatment duration 253.50 (IQR 212.50–418.50) days. Baseline and final DAS28 means differences were statistically significant (p=0.014).

Eight (50%) patients received Erelzi. 87.5% female, median age of 60.50 (IQR 46.00–69.00) years and median treatment duration of 143.50 (IQR 92.50–180.00) days. DAS28 difference was statistically not significant (p=0.068).

The use of biosimilar in these patients would suppose a saving of 27.47% versus the original drug (34.93% Benepali, 20% Erelzi).

Conclusion Effectiveness results were similar to the original drug. Both biosimilar drugs show a decrease in DAS28, although Erelzi was statistically not significant possibly because of its lower treatment length in this study. DAS28 difference was statistically significant in naive patients, however, in those who received more than two lines, there was not a decrease in this value.

The use of biosimilar drugs instead of original drugs entails an important saving.

These results require confirmation in long-term treatments.

References and/or acknowledgements Matsuno H, et al. Ann Rheum Dis 2018;77:488–94.

Emery P, et al. Rheumatology 2017;56:2093–2101.

No conflict of interest.