Efficacy and safety of original and biosimilar etanercept (SB4) in active rheumatoid arthritis – A comparison in a real-world national cohort

The study aims to compare the efficacy and safety of biosimilar etanercept (SB4) to original etanercept (ETN) in a real-life national cohort of rheumatoid arthritis (RA). Data from RA patients were retrieved electronically from the Romanian Registry of Rheumatic Diseases (RRBR), which contains all patients receiving biologics in the country. The study included 242 patients with efficacy and safety data after 6 months of treatment: 123 (50.8%) with ETN, 119 (49.2%) with SB4. There were no significant differences after 6 months regarding composite scores of RA activity between patients on ETN and SB4 (e.g. DAS28 remission: 18.7% in ETN group and 17.6% in SB4 group, p = 0.823; Boolean remission: 11.4% in ETN group and 11.8% in SB4 group, p = 0.926). There were 11 adverse events (AE) in the ETN subgroup (including 3 severe AE: lower respiratory tract infection, enterocolitis and anaphylaxis) and 12 AE in SB4 subgroup (including 4 severe AE: lower respiratory tract infection, vasculitis, anaphylaxis and rash). Biosimilar and original etanercept showed similar efficacy and safety after the first 6 months of treatment in RA patients from a national registry, which brings further evidence for biosimilarity in unselected patients in real-world setting.