An etanercept biosimilar is equivalent to its reference biologic in terms of efficacy at week 24 and has a similar safety profile and lower immunogenicity, a phase III study shows.

The  double-blind, parallel-group, multicentre study randomised 596 patients with moderate to severe RA to either the etanercept (ETN) biosimilar (SB4) or ETN.

The ACR20 response rate at week 24 in was 78.1% for SB4 and 80.3% for ETN, reported Paul Emery from the Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, UK, and colleagues in the Annals of the Rheumatic Diseases. 

“The 95% CI of the adjusted treatment difference was −9.41% to 4.98%, which is completely contained within the predefined equivalence margin of −15% to 15%, indicating therapeutic equivalence between SB4 and ETN,” they wrote.

Adverse events were comparable between the groups (55.2% vs 58.2%), and the incidence of antidrug antibody development up to week 24 was lower in SB4 compared with ETN (0.7% vs 13.1%).

“To date, this is the first global, multicentre study comparing an ETN biosimilar to reference product ETN. Confirmed equivalence of SB4 and ETN in this study may provide an alternative treatment option for RA and allow better access to biologics for patients,” they concluded.